Journal of Hazardous Materials (v.181, #1-3)

2,4,6-Triamino-1,3,5-trinitrobenzene (TATB) and TATB-based formulations—A review by Veera M. Boddu; Dabir S. Viswanath; Tushar K. Ghosh; R. Damavarapu (1-8).
This paper reviews the research and development work on 2,4,6-triamino-1,3,5-trinitrobenzene (TATB), and TATB-based formulations of other explosives. Syntheses including the production of nano-sized particles, analytical methods, thermophysical properties, performance, formulations, toxicity and safety of TATB are reviewed in this work.
Keywords: TATB; Synthesis; Structure; Physical and thermodynamic properties; Formulations; Review;

The applications of clay-based structured materials, excluding cordierites, for environmental protection are examined. In particular, their use in the abatement of some of the main hazardous species in polluted emissions such as nitrogen oxides, carbon monoxide, volatile organic compounds and heavy metals is discussed. A distinction is made between adsorption and catalytic processes. In addition, a general overview of the methods and general principles followed to prepare structured materials from clays is also given. Special attention is paid to those employed to obtain honeycomb monoliths and foams.
Keywords: Clay; Structured catalysts; Honeycomb monoliths; Environmental applications; Adsorption;

Both ammonium and nitrite act as substrates as well as potential inhibitors of anoxic ammonium-oxidizing (Anammox) bacteria. To satisfy demand of substrates for Anammox bacteria and to prevent substrate inhibition simultaneously; two strategies, namely high or low substrate concentration, were carefully compared in the operation of two Anammox upflow anaerobic sludge blanket (UASB) reactors fed with different substrate concentrations. The reactor working at relatively low influent substrate concentration (NO2 -N, 240 mg-N L−1) was shown to avoid the inhibition caused by nitrite and free ammonia. Using the strategy of low substrate concentration, a record super high volumetric nitrogen removal rate of 45.24 kg-N m−3  day−1 was noted after the operation of 230 days. To our knowledge, such a high value has not been reported previously. The evidence from transmission electron microscopy (TEM) showed that the morphology and ultrastructure of the Anammox cells in both the reactor enrichments was different.
Keywords: Anammox UASB reactor; Biological nitrogen removal; Substrate; Morphology; TEM;

Rice straw as precursor of activated carbons: Activation with ortho-phosphoric acid by V. Fierro; G. Muñiz; A.H. Basta; H. El-Saied; A. Celzard (27-34).
Highly mesoporous activated carbons (ACs) with a mesopore fraction ranging from 42 to 73% were obtained by activation of rice straw (RS) with ortho-phosphoric acid (PA). Due to such a high mesoporosity, these ACs can be successfully used for pollutant removal in aqueous phase. The ACs were prepared at activation temperatures (T) ranging from 350 to 500 °C, using PA to RS weight ratios (R) from 0 to 1.6 and activation times from 0 to 2 h. They were characterised by nitrogen adsorption at −196 °C, SEM-EDX, and methylene blue adsorption. RS is a very heterogeneous material with a variable content of mineral matter: using the product of activated carbon yield multiplied by surface area (C  ×  S BET ) as the performance criterion, the best AC was produced at T  = 450 °C and R  ≥ 1. These conditions lead to S BET higher than 500 m2  g−1 and a C  ×  S BET around 270 m2  g−1.
Keywords: Rice straw; Activated carbon; H3PO4; Methylene blue; Adsorption;

Mechanical and microstructural properties of alkali-activated fly ash geopolymers by M. Komljenović; Z. Baščarević; V. Bradić (35-42).
This paper investigates the properties of geopolymer obtained by alkali-activation of fly ash (FA), i.e. the influence of characteristics of the representative group of FA (class F) from Serbia, as well as that of the nature and concentration of various activators on mechanical and microstructural properties of geopolymers. Aqueous solutions of Ca(OH)2, NaOH, NaOH + Na2CO3, KOH and sodium silicate (water glass) of various concentrations were used as alkali activators. It was established that the nature and concentration of the activator was the most dominant parameter in the alkali-activation process. In respect of physical characteristics of FA, the key parameter was fineness. The geopolymer based on FA with the highest content of fine particles (<43 μm), showed the highest compressive strength in all cases. Regardless of FA characteristics, nature and concentration of the activator, the alkali-activation products were mainly amorphous. The formation of crystalline phases (zeolites) occurred in some cases, depending on the reaction conditions. The highest compressive strength was obtained using sodium silicate. Together with the increase of sodium silicate SiO2/Na2O mass ratio, the atomic Si/Al ratio in the reaction products was also increased. Under the experimental conditions of this investigation, high strength was directly related to the high Si/Al ratio.
Keywords: Fly ash; Alkali activation; Geopolymer;

Concentrations of particulate matter and arsenic in Bor (Serbia) by S.M. Šerbula; M.M. Antonijević; N.M. Milošević; S.M. Milić; A.A. Ilić (43-51).
Measurements of air quality in the territory of Bor (Serbia) were performed at the sampling sites in the urban-industrial, suburban and rural area during the 2003–2008 period. A high level of arsenic (As) concentration in suspended particulate matter (PM) is of a predominantly industrial origin. The major source of pollution is the copper smelter which is situated in the close vicinity of the urban area of Bor. The ambient level of PM and As is influenced by meteorological parameters as well as the remoteness from the copper smelter. Continual exceedances of the annual limit value (LV) for As (6 ng m−3) were recorded at the sampling sites in the urban-industrial and suburban area. Maximum annual As concentrations were recorded at Town Park (46.5 ng m−3) in 2004, Institute (95.4 ng m−3) in 2004 and Jugopetrol (74.5 ng m−3) in 2003. In the past 15 years not a single mean annual As concentration recorded at the sampling sites Town Park, Institute and Jugopetrol has been within the LV. When the average annual and maximum monthly As concentrations are compared, it can be concluded that the level of pollution is higher in the urban-industrial and suburban areas than in the rural area.
Keywords: Arsenic; Suspended particulate matter; PM10; Monitoring; Air pollution;

Removal of Pb(II), Cd(II) and Co(II) from aqueous solution using Garcinia mangostana L. fruit shell by R. Zein; R. Suhaili; F. Earnestly; Indrawati; E. Munaf (52-56).
This study examines the possibility of using mangosteen shell to remove low concentrations of lead, zinc and cobalt (less than 100 mg/l) from aqueous solution.It was found that the biosorption capacities were significantly affected by solution pH, contact time and initial metal ions concentration. Un-extracted and extracted dyes of mangosteen shell were investigated. Moreover higher pH up to 5 favoring higher metal ion removal. Kinetic and isotherm experiments were carried out at the optimal pH: at pH 5.0 for lead and zinc, and at pH 4.0 for cobalt. The metal removal rates were rapid, with 90% of the total adsorption taking place within 60 min. Mangosteen shell showed the highest potential for the removal of toxic metals in aqueous solution.
Keywords: Mangosteen shells; Biosorption; Toxic metals; FTIR;

δ-MnO2 coatings on clay substrates tend to be poorer in crystallinity as compared with their discrete counterparts, which may be of environmental significance for adsorption and oxidation of contaminants. Discrete δ-MnO2 particles and three δ-MnO2-coated montmorillonite complexes with varying MnO2 loadings (4.8–34.9%) were synthesized, and oxidative decolorization of methylene blue (MB) by the synthetic materials was investigated in batch systems. Results showed that oxidative decolorization of MB increased with increasing loading of Mn-oxide coatings, whereas oxidation capacity of the coatings, on the basis of unit mass of MnO2, tended to decrease. Initial reaction rate of MB oxidation by both δ-MnO2 coatings and their discrete counterpart increased linearly with increasing Mn-oxide loadings, but the rate of the former was higher than that of the latter. An increase in humic acid concentration displayed a progressively enhanced promotive effect on MB decolorization, whereas the promotive effect was greatly suppressed at lower pH.
Keywords: δ-MnO2 coatings; Montmorillonite; Methylene blue; Oxidative decolorization; Humic acid;

Long-term performance of aged waste forms treated by stabilization/solidification by Aurora Antemir; Colin D. Hills; Paula J. Carey; Kevin H. Gardner; Edward R. Bates; Alison K. Crumbie (65-73).
Current regulatory testing of stabilized/solidified (S/S) soils is based on short-term performance tests and is insufficient to determine their long-term stability or expected service life. In view of this, and the significant lack of data on long-term field performance in the literature, S/S material has been extracted from full-scale remedial operations and examined using a variety of analytical techniques to evaluate field performance. The results, including those from X-ray analytical techniques, optical and electron microscopy and leaching tests are presented and discussed. The microstructure of retrieved samples was found to be analogous to other cement-based materials, but varied according to the soil type, the contaminants present, the treatment applied and the field exposure conditions. Summary of the key microstructural features in the USA and UK is presented in this work. The work has shown that during 16 years of service the S/S wastes investigated performed satisfactorily.
Keywords: Stabilization/solidification; Microstructure; Mineralogy; Carbonation; Ettringite; Leaching;

Alkalinity, pH, and pCO2 are generally regarded as the most important parameters affecting trace element leaching from coal ashes. However, little is known about how those parameters are actually regulated in the field condition. This study investigated the processes controlling those parameters by observing undisturbed porewater chemistry in a closed ash disposal site. The site is now covered with 30–50 cm thick soils according to the management scheme suggested by the Waste Management Law of Korea and our results show the important role of soil cover regulating those parameters in the shallow porewater. Without the soil cover, the shallow porewater shows low pCO2 and alkalinity, and highly alkaline pH. In contrast, the porewater shows much higher alkalinity and near neutral pH range when the site was covered with the low permeability soils. This difference was caused by the CO2 supply condition changes associated with the changes in infiltration rate. The geochemical modeling shows that the calcite precipitations induced by porewater aging, dolomitization, and weathering of solid phases are the main processes controlling alkalinity, pH, and pCO2 in the deep saline porewaters. The weathering of coal ash plays the most important role decreasing the alkalinity in the deep porewater.
Keywords: Ash weathering; Soil cover; Saline porewater; Common ion effect; Calcite precipitation; Dolomitization;

Fly ash from a Mexican mineral coal I: Mineralogical and chemical characterization by Adriana Medina; Prócoro Gamero; Xavier Querol; Natalia Moreno; Beatriz De León; Manuel Almanza; Gregorio Vargas; María Izquierdo; Oriol Font (82-90).
The properties of coal fly ash are strongly dependent on the geological origin and the combustion process of the coal. It is important to characterize regional fly ash in detail to ascertain its potential uses as raw material in the production of high value products. The physicochemical properties of fly ash coming from the “Jose Lopez Portillo” coal-fired power plant, Coahuila, Mexico (MFA), are presented in this work. A detailed study of trace elements, the chemical composition of the amorphous phase, thermal stability and the leaching of contaminant elements under different conditions are included. MFA is composed of mullite, quartz, calcite, magnetite and an amorphous phase. This material contains mainly silica (59.6%), alumina (22.8%) and magnetite (5.6%). Its amorphous phase (78.3%) has a high silica (49.4%) and alumina (14.4%) content. According to its mineralogical and chemical composition, MFA is potentially useful as a raw material for making cement, silica, and alumina, as well as low silica/alumina ratio zeolites. Deleterious elements could be removed during the zeolitization process or with an additional acid treatment. Because of its morphological properties and structural and thermal stability, MFA can be used in thermal isolation and refractory materials and as a support for heterogeneous catalysts.
Keywords: Mexican fly ash; Characteristics; Potential use; Heavy metals; Leaching;

Fly ash from a Mexican mineral coal. II. Source of W zeolite and its effectiveness in arsenic (V) adsorption by Adriana Medina; Prócoro Gamero; José Manuel Almanza; Alfredo Vargas; Ascención Montoya; Gregorio Vargas; María Izquierdo (91-104).
Coal-fired plants in Coahuila (Mexico) produce highly reactive fly ash (MFA), which is used in a one-step process as a raw material in producing zeolite. We explored two routes in the synthesis of zeolite: (a) direct MFA zeolitization, which resulted in the formation of W zeolite with KOH and analcime with NaOH and (b) a MFA fusion route, which resulted in the formation of zeolite W or chabazite with KOH and zeolite X or P with NaOH. No residual crystalline phases were present. When LiOH was employed, ABW zeolite with quartz and mullite were obtained. For both zeolitization routes, the nature of the alkali (KOH, NaOH, LiOH), the alkali/MFA ratio (0.23–1.46), and the crystallization temperature and time (90–175 °C; 8–24 h) were evaluated. Additionally, the effect of temperature and time on MFA fusion was studied. W zeolite was obtained by both zeolitization methods. The direct route is preferred because it is a straightforward method using soft reaction conditions that results in a high yield of low cost zeolites with large crystal agglomerates. It was demonstrated that aluminum modified W zeolite has the ability to remove 99% of the arsenic (V) from an aqueous solution of Na2HAsO4·7H2O originally containing 740 ppb.
Keywords: Mexican fly ash; W zeolite; Direct method; Merlinoite; Arsenic adsorption;

Risk assessment of gaseous/particulate phase PAH exposure in foundry industry by Hung-Hsin Liu; Hsi-Hsien Yang; Choa-Da Chou; Ming-Hsiu Lin; Hsiu-Ling Chen (105-111).
Thirty-seven air samplings in different working areas of two foundry industries were collected to assess polycyclic aromatic hydrocarbon (PAH) levels. The average PAH level inside Foundry A was 19.56 μg/m3, which was higher than that in Foundry B (8.26 μg/m3), whereas for the benzo[a]pyrene toxic equivalent (BaPeq) level (38.81 ng/m3 vs. 46.52 ng/m3). A higher PAH level was found for big moulding process than for the small one, and the chemical binder in the different size moulds was hypothesized to be the main cause. The higher PAH levels were found in the painting area (95.51 μg/m3), pouring area (18.42 μg/m3), and inside the office (16.48 μg/m3); as well as the higher BaPeq level was in the painting area (152.3 ng/m3), and the furnace for melting iron (96.9 ng/m3). The gas phase (over 90%) was the major contributor of total PAHs in the manufacturing areas. Moreover, health risk assessment of PAHs exposure showed that lung cancer risks were 9.06 × 10−4 and 1.09 × 10−3 in Foundries A and B, respectively. This study suggests that the workers shall use appropriate respiratory masks in painting, melting, and pouring areas to prevent their occupational exposure to PAHs.
Keywords: PAH; Foundry; Benzo[a]pyrene; BaP; Risk assessment;

The decolorization of Acid Orange II in non-homogeneous Fenton reaction catalyzed by natural vanadium–titanium magnetite by Xiaoliang Liang; Yuanhong Zhong; Sanyuan Zhu; Jianxi Zhu; Peng Yuan; Hongping He; Jing Zhang (112-120).
The catalytic activity of natural vanadium–titanium magnetite was investigated in the decolorization of Acid Orange II by non-homogeneous Fenton process. The natural catalysts purified by magnetic separation were characterized using X-ray diffraction (XRD), polarizing microscope, X-ray absorption fine structure (XAFS) analysis and Mössbauer spectroscopy. The obtained results show that the natural samples after magnetic separation mainly contain titanomagnetite, with a small amount of ilmenite and chlorite. Titanomagnetite is doped with vanadium, whose the valency is mainly +3 and occupies the octahedral site. Batch decolorization studies were performed to evaluate the influences of various experimental parameters like initial pH, the amount of catalyst and initial concentration of hydrogen peroxide on the decolorization efficiency of Acid Orange II. The decolorization of the dye mainly relied on degradation. The degradation efficiency was strongly dependent on pH of the medium where it increased as the pH decreased in acid range. The increase of catalyst and hydrogen peroxide could accelerate the degradation. The catalytic property of natural vanadium–titanium magnetite in the degradation of Acid Orange II was stronger than that of synthetic magnetite (Fe3O4). The catalytic activity of the natural samples was greatly related to the titanomagnetite content. The degradation process was dominated by heterogeneous Fenton reaction, complying with pseudo-first-order rate law. The natural catalyst has a good catalytic stability.
Keywords: Natural vanadium–titanium magnetite; Non-homogeneous Fenton reaction; Degradation; Acid Orange II; Catalyst;

Sorption properties of greenwaste biochar for two triazine pesticides by Wei Zheng; Mingxin Guo; Teresa Chow; Douglas N. Bennett; Nandakishore Rajagopalan (121-126).
Biochar is a carbon-rich product generated from biomass through pyrolysis. This study evaluated the ability of an unmodified biochar to sorb two triazine pesticides – atrazine and simazine, and thereby explored potential environmental values of biochar on mitigating pesticide pollution in agricultural production and removing contaminants from wastewater. A greenwaste biochar was produced by heating waste biomass under the oxygen-limited condition at 450 °C. The effects of several experimental parameters, including biochar particle size, contact time, solid/solution ratio, and solution pH on the sorption of atrazine and simazine were comprehensively investigated. The biochar with small particle size needed less time to reach sorption equilibrium. The sorption affinity of the biochar for the two pesticides increased with decreasing solid/solution ratio. The sorbed amounts (C s) of atrazine and simazine increased from 451 to 1158 mg/kg and 243 to 1066 mg/kg, respectively, when the solid/solution ratio decreased from 1:50 to 1:1000 (g/mL). The sorption of the biochar for both pesticides was favored by low pH. The sorption isotherms of atrazine and simazine on the biochar are nonlinear and follow a Freundlich model. When atrazine and simazine co-existed, a competitive sorption occurred between these two pesticides on the biochar, reflecting a decrease in sorption capacity (K f) from 435 to 286 for atrazine and from 514 to 212 for simazine. Combined adsorption and partition mechanisms well depicted sorption of atrazine and simazine on carbonized and noncarbonized fractions of the biochar in the single-solute and co-solute systems.
Keywords: Biochar; Atrazine; Simazine; Sorption; Competitive sorption;

Coagulation–Fenton coupled treatment for ecotoxicity reduction in highly polluted industrial wastewater by J.A. Perdigón-Melón; J.B. Carbajo; A.L. Petre; R. Rosal; E. García-Calvo (127-132).
A coupled coagulation–Fenton process was applied for the treatment of cosmetic industry effluents. In a first step, FeSO4 was used as coagulant and the non-precipitated Fe2+ remaining in dissolution was used as catalyst in the further Fenton process. In the coagulation process a huge decrease in total organic carbon (TOC) was achieved, but the high concentration of phenol derivatives was not diminished. The decrease in TOC in the coagulation step significantly reduces the amount of H2O2 required in the Fenton process for phenol depletion. The coupled process, using a H2O2 dose of only 2 g l−1, reduced TOC and total phenol to values lower than 40 and 0.10 mg l−1, respectively. The short reaction period (less than 15 min) in TOC and phenol degradation bodes well for improving treatment in a continuous regime. The combination of both processes significantly reduced the ecotoxicity of raw effluent and markedly increased its biodegradability, thus allowing easier treatment by the conventional biological units in conventional sewage treatment plants (STPs).
Keywords: Cosmetic industry wastewater; Total phenol; Coagulation; Fenton's reagent; Ecotoxicity;

Carbon content reduction in a model reluctant clayey soil: Slurry phase n-hexadecane bioremediation by Ali Partovinia; Fereshteh Naeimpoor; Parisa Hejazi (133-139).
Clayey soils contaminated with organic pollutants are nowadays one of the important environmental issues as they are highly reluctant to conventional bioremediation techniques. In this study, biodegradability of n-hexadecane as a model contaminant in oil polluted clayey soil by an indigenous bacterium was investigated. Maximal bacterial growth was achieved at 8% (v/v) n-hexadecane as sole carbon and energy sources in aqueous phase. The predominant n-hexadecane uptake mechanism was identified to be biosurfactant-mediated using bacterial adhesion to hydrocarbon (BATH) test and surface tension measurements. The effect of n-hexadecane concentration, soil to water ratio, inoculum concentration and pH on total organic carbon (TOC) reduction from kaolin soil in slurry phase was investigated at two levels in shake flasks using full factorial experimental design method where 10,000 (mg n-hexadecane)(kg soil)−1, soil–water ratio of 1:3, 10% (v/w) inoculum and pH of 7 resulted in the highest TOC reduction of 70% within 20 days. Additionally, slurry bioreactor experiments were performed to study the effect of various aeration rates on n-hexadecane biodegradation during 9 days where 2.5 vvm was found as an appropriate aeration rate leading to 54% TOC reduction. Slurry phase bioremediation is shown to be a successful method for remediation of clayey reluctant soils.
Keywords: Bioremediation; Clayey soil; Contaminated soil; n-Hexadecane; Slurry bioreactor;

Two PVC membrane ion selective electrodes for Pb(II) ion based on two bis-thioureas: 1,3-bis(N′-benzoylthioureido)benzene and 1,3-bis(N′-furoylthioureido)benzene as ionophores, are reported. A first membrane formulated using 1,3-bis(N′-benzoylthioureido)benzene as carrier exhibited a Nernstian response to Pb(II) over a wide concentration range (4.0 × 10−6 to 1.0 × 10−2  M) with a slope of 31.5 ± 1.6 mV/dec. It showed a fast response time (t 90%  = 14 s) and could be used for 10 weeks without any divergence in potentials. The membrane formulated using 1,3-bis(N′-furoylthioureido)benzene as carrier exhibited a Nernstian response in the concentration range (5.0 × 10−6 to 1.0 × 10−2  M), with a slope of 30.0 ± 1.3 mV/dec. Its response time was t 90%  = 14 s, and it could be used for 14 weeks without any divergence in potentials. The two proposed potentiometric sensors revealed acceptable selectivities for Pb(II) over a wide variety of other metal ions and could be used in a pH range of 2.2–6.0. Both electrodes were assayed in direct potentiometric determination of lead in soils (10–30 mg/kg range) with very good performance (0.99935 correlation coefficient in the comparison against ICP-MS method).
Keywords: Lead ion selective electrode; Bis-thiourea; PVC membrane; Potentiometric sensor;

Soluble substrates (electron donors) have been commonly injected into chlorinated solvent contaminated plume to stimulate reductive dechlorination. Recently, different types of organic mulches with economic advantages and sustainable benefits have received much attention as new supporting materials that can provide long term sources of electron donors for chlorinated solvent bioremediation in engineered biowall systems. However, sorption capacities of organic mulches for chlorinated solvents have not been studied yet. In this study, the physiochemical properties of organic mulches (pine, hardwood and cypress mulches) were measured and their adsorption capacity as a potential media was elucidated. Single, binary and quaternary isotherm tests were conducted with trichloroethylene (TCE), tetrachloroethylene (PCE), trans-dichloroethylene (trans-DCE) and cis-dichloroethylene (cis-DCE). Among the three tested mulches, pine mulch showed the highest sorption capacity for the majority of the tested chemicals in single isotherm test. In binary or quaternary isotherm tests, competition among chemicals appears to diminish the differences in Q e for tested mulches. However, pine mulch also showed higher adsorption capacity for most chemicals when compared to hardwood and cypress mulches in the two isotherm tests. Based upon physicochemical properties of the three mulches, higher sorption capacity of pine mulch over hardwood and cypress mulches appears to be attributed to a higher organic carbon content and the lower polarity.
Keywords: Trichloroethylene; Adsorption; Sustainability; Organic mulch;

A very effective sorbent material which exhibits exceptional capture of hexavalent uranium from other actinides and lanthanides at μg g−1 level, features pyridine 2,6-dimethanol immobilized onto alumina. The maximum sorption capacity for dioxouranium(VI) was found as 1.96 mmol g−1 at pH 3.0. The adsorbed uranium complex was eluted completely by 0.05 mol L−1 (NH4)2CO3 solution and the concentration of hexavalent dioxouranium ion was monitored spectrophotometrically using Arsenazo III. The structure of the chelated uranium complex has been confirmed by single crystal X-ray structure analysis and Fourier transform infrared red (FTIR) spectroscopy. Thermo gravimetric analysis/differential thermo gravimetric analysis (TGA/DTG) of the chelated uranium complex was performed. The method is reproducible with a relative standard deviation (RSD) of 1.2% (N  = 10) and the three sigma detection limits (N  = 15) 1.2 μg mL−1 respectively. A pre-concentration factor, almost 500, for uranium was achieved. Interferences from Th4+, Mn2+, Ni2+ and Cu2+ ions were masked with ethylene diamine tetra acetic acid (di-sodium salt) (Na2EDTA) in the aqueous phase. The developed method has been tested for uranium recovery and estimation in some certified reference materials and environmental samples.
Keywords: Uranium recovery; Chelation; Pyridine 2,6-dimethanol; Single crystal X-ray structure; Arsenazo III; Spectrophotometry;

Assessing the cancer risk associated with arsenic-contaminated seafood by Bo-Ching Chen; Wei-Chun Chou; Wei-Yu Chen; Chung-Min Liao (161-169).
Tens of millions of people worldwide ingest excessive amounts of arsenic (As) through drinking water and food. The dietary intake of seafood is the major As exposure route in humans and can cause As-related adverse health effects including cancers. The aim of this study was to quantify potential cancer risks of As exposure for children and adults through seafood consumption. By coupling the age-specific physiologically based pharmacokinetic (PBPK) model and a Weibull-based dose–response function, a more accurate estimate of urinary arsenic metabolites could be achieved to better characterize potential cancer risks. The simulation results show that the proportion of inorganic As, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in human urine are estimated to total 6.7, 26.9, and 66.4% for children, and 6.2, 27.4, and 66.4% for adults, respectively. The estimated median cumulative cancer incidence ratios were respectively 2.67 × 10−6 and 3.83 × 10−6 for children and adults, indicating a low cancer risk for local residents exposed to As through the consumption of seafood. However, it is necessary to incorporate other exposure routes into the model to make it more realistic. The methodology proposed here can not only be applied to calculate the concentrations of As metabolites in urine, but also to provide a direct estimation of adverse health effects caused by the calculated internal concentrations.
Keywords: Arsenic; Cancer risk; Physiologically based pharmacokinetic model; Seafood; Urine;

Ground water flow and geochemical reactive transport models were used to assess the effectiveness of five strategies used to limit fouling and to enhance the long-term hydraulic behavior of continuous-wall permeable reactive barriers (PRBs) employing granular zero valent iron (ZVI). The flow model accounted for geological heterogeneity and the reactive transport model included a geochemical algorithm for simulating iron corrosion and mineral precipitation reactions that have been observed in ZVI PRBs. The five strategies that were evaluated are pea gravel equalization zones, a sacrificial pre-treatment zone, pH adjustment, large ZVI particles, and mechanical treatment. Results of simulations show that installation of pea gravel equalization zones results in flow equalization and a more uniform distribution of residence times within the PRB. Residence times within the PRB are less affected by mineral precipitation when a pre-treatment zone is employed. pH adjustment limits the total amount of hydroxide ions in ground water to reduce porosity reduction and to retain larger residence times. Larger ZVI particles reduce porosity reduction as a result of the smaller iron surface area for iron corrosion, and retain longer residence time. Mechanical treatment redistributes the porosity uniformly throughout the PRB over time, which is effective in maintaining residence time.
Keywords: Permeable reactive barrier; Fouling; Reactive transport; Heterogeneity; Residence time;

Advanced oxidation of benzene, toluene, ethylbenzene and xylene isomers (BTEX) by Trametes versicolor by Elisabet Aranda; Ernest Marco-Urrea; Gloria Caminal; María E. Arias; Inmaculada García-Romera; Francisco Guillén (181-186).
Advanced oxidation of benzene, toluene, ethylbenzene, and o-, m-, and p-xylene (BTEX) by the extracellular hydroxyl radicals (•OH) generated by the white-rot fungus Trametes versicolor is for the first time demonstrated. The production of •OH was induced by incubating the fungus with 2,6-dimethoxy-1,4-benzoquinone (DBQ) and Fe3+–EDTA. Under these conditions, •OH were generated through DBQ redox cycling catalyzed by quinone reductase and laccase. The capability of T. versicolor growing in malt extract medium to produce •OH by this mechanism was shown during primary and secondary metabolism, and was quantitatively modulated by the replacement of EDTA by oxalate and Mn2+ addition to DBQ incubations. Oxidation of BTEX was observed only under •OH induction conditions. •OH involvement was inferred from the high correlation observed between the rates at which they were produced under different DBQ redox cycling conditions and those of benzene removal, and the production of phenol as a typical hydroxylation product of •OH attack on benzene. All the BTEX compounds (500 μM) were oxidized at a similar rate, reaching an average of 71% degradation in 6 h samples. After this time oxidation stopped due to O2 depletion in the closed vials used in the incubations.
Keywords: BTEX degradation; Advanced oxidation; Hydroxyl radical; Trametes versicolor;

Photochemical decomposition of perfluorodecanoic acid in aqueous solution with VUV light irradiation by B.B. Wang; M.H. Cao; Z.J. Tan; L.L. Wang; S.H. Yuan; J. Chen (187-192).
The photochemical decomposition of perfluorodecanoic acid (PFDeA) in water in the presence of persulfate ion (S2O8 2−) and sulfur ion (S2−) was investigated under vacuum ultraviolet (VUV) light irradiation. PFDeA was decomposed under VUV light irradiation. With the addition of S2O8 2− or S2−, the photo-decomposition and defluorination of PFDeA were enhanced significantly. Sulfate radical anion (SO4 ) generated from photolysis of S2O8 2− initiated PFDeA oxidation. While the S2− ion, acting as a OH scavenger, enhanced the role of reduction pathway induced by aqueous electrons (eaq ). The shorter-chain perfluorocarboxylic acids (PFCAs), formed in a stepwise manner from longer-chain PFCAs, were identified as products by HPLC/MS.
Keywords: Photochemical decomposition; Perfluorodecanoic acid; VUV light; Defluorination;

Radiological, chemical and morphological characterizations of phosphate rock and phosphogypsum from phosphoric acid factories in SW Spain by Marusia Rentería-Villalobos; Ignacio Vioque; Juan Mantero; Guillermo Manjón (193-203).
In this work, radiological, chemical, and also morphological characterization was performed in phosphate rock and phosphogypsum samples, in order to understand the behavior of toxic elements. Characterization was carried out using X-ray diffraction (XRD), X-ray fluorescence (XRF), gamma spectrometry and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX). Our results show that the phosphate rock was mainly composed of fluorapatite, calcite, perovskite, quartz, magnetite, pyrite and kaolinite, whereas phosphogypsum only exhibited dihydrated calcium sulfate. The activity concentration of U-series radioisotopes in phosphate rock was around 1640 Bq/kg. 226Ra and 210Pb tend to be distributed into phosphogypsum by up to 80%, whereas the fraction of U-isotopes is 10%. The most abundant trace elements in phosphate rock were Sr, Cr, V, Zn, Y, Ni and Ba. Some elements, such as Ba, Cd, Cu, La, Pb, Se, Sr, Th and Y, were enriched in the phosphogypsum. This enrichment may be attributed to an additional input associated to the sulfuric acid used for the phosphoric acid production. Furthermore, results from SEM-EDX demonstrated that toxic elements are not distributed homogeneously into phosphogypsum. Most of these elements are concentrated in particles <20 μm of high porosity, and could be easily mobilized by leaching and/or erosion.
Keywords: Radioactivity; Chemical speciation; Morphology; Phosphate rock; Phosphogypsum;

Mesoporous TiO2 was synthesized by a hydrothermal method using cetyltrimethyl ammonium bromide (CTAB) as a structure-directing agent, and its adsorption abilities for the removal of methyl orange (MO) and Cr(VI) from waste waters were investigated. Transmission electron micrograph (TEM) observations together with nitrogen adsorption–desorption measurements show the formation of mesoporous TiO2 with an average pore size of 5.2 nm and a surface area of 161.2 m2/g. The adsorption data for both MO and Cr(VI) fit well with either Langmuir or Freundlich adsorption model. The adsorption for MO is slightly influenced by pH of the solutions, while that for Cr(VI) is strongly dependent on solution pH. By an increase in solution pH from 3 to 12, the adsorbed percentage of MO decreases from ca. 87 to 78%; however, the adsorbed percentage of Cr(VI) decreases from ca. 45 to 0%. The maximum adsorption capacities of the mesoporous TiO2 for MO and Cr(VI) are determined to be 454.5 and 33.9 mg/g, respectively, which suggests that the mesoporous TiO2 is an excellent adsorbent for MO and Cr(VI).
Keywords: Adsorption; Water treatment; Mesoporous TiO2; Methyl orange; Chromium;

Transfer of heavy metals from compost to red soil and groundwater under simulated rainfall conditions by Guiqiu Chen; Guangming Zeng; Chunyan Du; Danlian Huang; Lin Tang; Liang Wang; Guoli Shen (211-216).
It is well known that compost can be polluted with heavy metals. A self-designed soil column system was used to clarify the leaching or residue of heavy metals when compost was added to red soil. Less than 4% of Cu and more than 58.3% of Zn were transferred to groundwater. Maximum concentrations of Cu and Zn in leachate were 22 and 246 μg/L, respectively. pH in leachate decreased during 6.75–11.25 h, comparing with the control. Electrical conductivity was higher in the treatment of compost polluted by both Cu and Zn than that polluted only by Cu. Over 75.3% of Cu and 78.2% of Zn remained in the residual formation. Maximum bioavailability parameters in soil were 0.099 for Cu and 0.160 for Zn. Long-term field experiments with cycling application are needed to study the cycling effect on heavy metal residue in soil or leaching to the groundwater in the future.
Keywords: Compost; Heavy metals; Rainfall; Soil; Groundwater;

Stability investigations of zinc and cobalt precipitates immobilized by in situ bioprecipitation (ISBP) process by Yamini Satyawali; Edo Schols; Sandra Van Roy; Winnie Dejonghe; Ludo Diels; Karolien Vanbroekhoven (217-225).
In situ bioprecipitation (ISBP), which involves immobilizing the metals as precipitates (mainly sulphides) in the solid phase, is an effective method of metal removal from contaminated groundwater. This study investigated the stability of metal precipitates formed after ISBP in two different solid–liquid matrices (artificial and natural). The artificial matrix consisted of sand, Zn (200 mg L−1), artificial groundwater and a carbon source (electron donor). Here the stability of the Zn precipitates was evaluated by manipulation of redox and pH. The natural system matrices included aquifer material and groundwater samples collected from three different metal (Zn and Co) contaminated sites and different carbon sources were provided as electron donors. In the natural matrices, metal precipitates stability was assessed by changing aquifer redox conditions, sequential extraction, and BIOMET® assay. The results indicated that, in the artificial matrix, redox manipulation did not impact the Zn precipitates. However the sequential pH change proved detrimental, releasing 58% of the precipitated Zn back into liquid phase. In natural matrices, the applied carbon source largely affected the stability of metal precipitates. Elemental analysis performed on the precipitates formed in natural matrix showed that the main elements of the precipitates were sulphur with Zn and Co.
Keywords: Heavy metal; Precipitate; In situ bioprecipitation; Stability; Redox; pH;

Clean-up of contaminated sites is usually based on a risk-based approach for the definition of the remediation goals, which relies on the well known ASTM-RBCA standard procedure. In this procedure, migration of contaminants is described through simple analytical models and the source contaminants’ concentration is supposed to be constant throughout the entire exposure period, i.e. 25–30 years. The latter assumption may often result over-protective of human health, leading to unrealistically low remediation goals. The aim of this work is to propose an alternative model taking in account the source depletion, while keeping the original simplicity and analytical form of the ASTM-RBCA approach. The results obtained by the application of this model are compared with those provided by the traditional ASTM-RBCA approach, by a model based on the source depletion algorithm of the RBCA ToolKit software and by a numerical model, allowing to assess its feasibility for inclusion in risk analysis procedures. The results discussed in this work are limited to on-site exposure to contaminated water by ingestion, but the approach proposed can be extended to other exposure pathways.
Keywords: Contaminated sites; Risk analysis; Fate and transport; Exposure duration; On-site receptors; Depleting source;

Ambient air pollution and hospital admission in Shanghai, China by Renjie Chen; Chen Chu; Jianguo Tan; Junshan Cao; Weimin Song; Xiaohui Xu; Cheng Jiang; Wenjuan Ma; Chunxue Yang; Bingheng Chen; Yonghao Gui; Haidong Kan (234-240).
No prior studies exist in Mainland China examining the association of outdoor air pollution with hospital admissions. In this study, we conducted a time-series analysis to examine the association of outdoor air pollutants (PM10, SO2, and NO2) with both total and cause-specific hospital admission in Shanghai, using three years of daily data (2005–2007). Hospital admission and air pollution data were collected from the Shanghai Health Insurance Bureau and Shanghai Environmental Monitoring Center. Natural spline model was used to analyze the data. We found outdoor air pollution was associated with increased risk of total and cardiovascular hospital admission in Shanghai. The effect estimates of air pollutants varied by lag (L) structures of pollutants’ concentrations. For lag 5, a 10 μg/m3 increase in concentration of PM10, SO2 and NO2 corresponded to 0.18% (95% CI: −0.15%, 0.52%), 0.63% (95% CI: 0.03%, 1.23%), and 0.99% (95% CI: 0.10%, 1.88%) increase of total hospital admission; and 0.23% (95% CI: −0.03%, 0.48%), 0.65% (95% CI: 0.19%, 1.12%), and 0.80% (95% CI: 0.10%, 1.49%) increase of cardiovascular hospital admission. The associations appeared to be more evident in the cool season (from November to April) than in the warm season (from May to October). We found significant effects of gaseous pollutants (SO2 and NO2) after adjustment for PM10. Our analyses provide the first evidence in China that the current air pollution level has an effect on hospital admission and strengthen the rationale for further limiting air pollution levels in Shanghai.
Keywords: Air pollution; Hospital admission; Morbidity; Time-series;

The removal of 13 polycyclic aromatic hydrocarbons, 7 polychlorobiphenyls and nonylphenol was measured during the continuous anaerobic digestion of five different sludge samples. The reactors were fed with one of the following: primary/secondary sludge (PS/SS), thermally treated PS, cellulose-added SS, or SS augmented with dissolved and colloidal matter (DCM). These various feeding conditions induced variable levels of micropollutant bioavailability (assumed to limit their biodegradation) and overall metabolism (supposed to be linked to micropollutant metabolism throughout co-metabolism). On the one hand, overall metabolism was higher with secondary sludge than with primary and the same was observed for micropollutant removal. However, when overall metabolism was enhanced thanks to cellulose addition, a negative influence on micropollutant removal was observed. This suggests that either the co-metabolic synergy would be linked to a specific metabolism or co-metabolism was not the limiting factor in this case. On the other hand, micropollutant bioavailability was presumably diminished by thermal treatment and increased by DCM addition. In both cases, micropollutant removal was reduced. These results suggest that neither overall metabolism nor bioavailability would absolutely limit micropollutant removal. Each phenomenon might alternatively predominate depending on the feed characteristics.
Keywords: Bioavailability; Biodegradation; Cellulose; Co-metabolism; Thermal treatment;

The formation of struvite (MgNH4PO4·6H2O) in wastewater treatment plants can lead to scaling and thus operational problems reducing the treatment efficiency. However, struvite has significant commercial value as an agricultural fertilizer. Therefore, controlled struvite formation in wastewater treatment plants not only presents an opportunity to recover nutrients but also corresponds to the valorization of wastes. NH4–N and PO4–P removal and recovery from the effluent of a full-scale sewage sludge anaerobic digester via controlled struvite precipitation were investigated in this study. The effect of the residual heavy metal and micropollutant content of the formed struvite on fertilizer quality was also evaluated. Removal efficiencies of NH4–N, PO4–P and COD were 89.35%, 95% and 39.78% when Mg:N:P molar ratio was 1.5:1:1 and pH was 9.0. Mercury, nickel, zinc and chrome concentrations derived from struvite precipitation were below the regulatory limit for fertilizer usage in Turkey. The precipitate did not contain polychlorinated biphenyls (PCB). X-ray diffraction (XRD) analysis conducted on the precipitate indicated a struvite formation.
Keywords: Anaerobic digester; Fertilizer quality; Heavy metal; Micropollutant; Struvite precipitation;

Radiological and instrumental neutron activation analysis determined characteristics of size-fractionated fly ash by T.K. Peppas; K.L. Karfopoulos; D.J. Karangelos; P.K. Rouni; M.J. Anagnostakis; S.E. Simopoulos (255-262).
The concentration of trace elements and radionuclides in fly ash particles of different size can exhibit significant variation, due to the various processes taking place during combustion inside a coal-fired power plant. An investigation of this effect has been performed by analyzing samples of fly ash originating in two different coal-fired power plants, after separation into size fractions by sieving. The samples were analyzed by gamma-ray spectrometry, including low-energy techniques, radon exhalation measurement and instrumental neutron activation analysis for the determination of Al, As, Ga, K, La, Na, Mn, Mg, Sr, Sc, and V. Variations are observed in the results of various samples analyzed, while the activity balances calculated from the results of individual size fractions are consistent with those of the raw ash samples. Correlations among the radionuclides examined are also observed, while individual nuclide behavior varies between the two types of fly ash examined.
Keywords: Fly ash; Radioactivity; Radon exhalation; INAA;

Communal action of microbial cultures for Red HE3B degradation by P.S. Patil; S.S. Phugare; S.B. Jadhav; J.P. Jadhav (263-270).
The consortium PMB11 consisting of three bacterial species, originally isolated from dye contaminated soil was identified as Bacillus odysseyi SUK3, Morganella morganii SUK5 and Proteus sp. SUK7. The consortium possessed the ability to decolorize various textile dyes as well as mixtures of dyes. PMB11 could decolorize Red HE3B (50 mg l−1) with 99% of decolorization within 12 h in nutrient broth, while in mineral medium it could decolorize up to 97% within 24 h. Induction in the activities of various oxidative and reductive enzymes indicates the involvement of these enzymes in decolorization. Biodegradation of the dye was monitored using UV–vis spectroscopy, HPLC and FTIR analysis. The Red HE3B degradation pathway was proposed by GC–MS analysis. Various metabolites formed after the degradation were identified as 2,5-diaminobenzene 6-aminotriazine, aniline 2-sulfate, aniline 3-sulfate, 2-amino 5-chlorotriazine and naphthalene. Phytotoxicity studies revealed that metabolites formed after degradation were significantly less toxic in nature.
Keywords: Biodegradation; Consortium PMB11; Red HE3B; Azoreductase; Phytotoxicity;

Adsorption of Malachite Green dye onto activated carbon derived from Borassus aethiopum flower biomass by S. Nethaji; A. Sivasamy; G. Thennarasu; S. Saravanan (271-280).
In the present study, chemically prepared activated carbon derived from Borassus aethiopum flower was used as adsorbent. Batch adsorption studies were performed for the removal of Malachite Green (MG) from aqueous solutions by varying the parameters like initial solution pH, adsorbent dosage, initial MG concentration and temperature with three different particle sizes such as 100 μm, 600 μm and 1000 μm. The zero point charge was 2.5 and the maximum adsorption occurred at the pH range from 6.0 to 8.0. Experimental data were analyzed by model equations such as Langmuir, Freundlich and Temkin isotherms and it was found that the Langmuir isotherm model best fitted the adsorption data. Thermodynamic parameters such as ΔG, ΔH and ΔS were also calculated for the adsorption processes. Adsorption rate constants were determined using pseudo first-order, pseudo second-order rate equations and also Elovich model and intraparticle diffusion models. The results clearly showed that the adsorption of MG onto PFAC followed pseudo second-order model and the adsorption was both by film diffusion and by intraparticle diffusion.
Keywords: Palm flower activated carbon; Malachite Green; Adsorption isotherms; Kinetics; Thermodynamics;

We have investigated bacterial populations relevant to nitrification in a full-scale activated sludge plant receiving wastewater from a petroleum refinery showing unstable nitrification. Inhibition of ammonia oxidation was related to phenol concentration according to a model of non-competitive inhibition. While the number of ammonia-oxidizing bacteria (AOB) did not correlate with nitrification performance, the total number of nitrite-oxidizing bacteria (NOB) dropped considerably during periods of nitrite accumulation or no nitrification. Diversity of nitrifiers in the sludge of the full-scale facility was examined at a time of full nitrification with the construction of clone libraries of ammonia monooxygenase (amoA) gene and of the 16S rRNA gene of NOB. Nucleotide sequences of amoA gene belonged to one dominant population, associated with Nitrosomonas europaea, and to a minor population related to the Nitrosomonas nitrosa lineage. The majority of sequences retrieved in the NOB-like clone library also clustered within a single operational taxonomic unit. The high dominance of Nitrobacter over Nitrospira and the low diversity of nitrifying bacteria observed in this wastewater treatment plant might account for the increased risk of failure in the presence of disturbances.
Keywords: Nitrification; Phenol; Ammonia-oxidizing bacteria; Nitrobacter; Activated sludge;

Biological treatment of landfill leachate is a concern due to toxicity, high ammonia, low biodegradable organic matter concentrations, and low carbon-to-nitrogen ratio. To study the reliability and commercial viability of leachate treatment using an integrated liquid–solid circulating fluidized bed bioreactor (LSCFB), a pilot-scale LSCFB was established at the Adelaide Pollution Control Plant, London, Ontario, Canada. Anoxic and aerobic columns were used to optimize carbon and nutrient removal capability from leachate using 600 μm lava rock with a total porosity of 61%, at empty bed contact times (EBCTs) of 0.55, 0.49, and 0.41 d. The LSCFB achieved COD, nitrogen, and phosphorus removal efficiencies of 85%, 80%, and 70%, respectively at a low carbon-to-nitrogen ratio of 3:1 and nutrients loading rates of 2.15 kg COD/(m3  d), 0.70 kg N/(m3  d), and 0.014 kg P/(m3  d), as compared with 60–77% COD and 70–79% nitrogen removal efficiencies achieved by upflow anaerobic sludge blanket (UASB) and moving bed bioreactor (MBBR), respectively. The LSCFB effluent characterized by ≤35 mg SBOD/L, <35 mg NH4-N/L, <1.0 mg PO4-P/L, and 37 mg VSS/L can easily meet sewer by-law requirements. Remarkably low yields of 0.13, 0.15, and 0.16 g VSS/g COD were observed at long biological solids retention times (SRTs) of 31, 38 and 44 d.
Keywords: Landfill leachate; Liquid–solid circulating fluidized bed; Nitrification; Denitrification; Biomass yield;

Reduction of cadmium uptake in spinach (Spinacia oleracea L.) by soil amendment with animal waste compost by Atsushi Sato; Hiroyuki Takeda; Wataru Oyanagi; Eiji Nishihara; Masaharu Murakami (298-304).
A field experiment was conducted to evaluate the efficacy of animal waste compost (AWC) in reducing Cd uptake by spinach (Spinacia oleracea L.). Spinach was grown in a field that had been treated by having cattle, swine, or poultry waste compost incorporated into the soil before each crop throughout 4 years of rotational vegetable production. Cadmium concentration was 34–38% lower in spinach harvested from the AWC-treated soils than in the chemical fertilizer-treated soil. Although the repeated application of swine and poultry compost caused significant P accumulation in the cropped soils, that of cattle compost did not. These results indicate that cattle compost with high affinity for Cd and low P content should be the preferred soil amendment when used to reduce Cd uptake by spinach.
Keywords: Cadmium phytoavailability; Spinach; Animal waste compost;

Combustion characteristics of particles of hazardous solid waste mixtures in a fixed bed by Ling Tao; Guangbo Zhao; Rui Sun; Qiang Wang (305-314).
Hazardous waste disposal is vitally important as industrial production increases. Grate furnaces are a common means to incinerate hazardous waste. In this present work, a fixed bed assembly is used to experimentally model combustion within grate furnaces. Combustion characteristics are examined and the effects of primary air rate, moisture, bed height and particle size on burning rate, ignition-front speed and temperatures in the bed are also investigated. The results indicate that a rising temperature front descends through the bed while weight loss remains constant during the main combustion stage. Primary air rates and moisture content are shown to have significant effects on burning rates and average ignition-front speeds. Bed height has no effect on burning rates but does have an effect on average ignition-front speeds. Particle size is found to have slight effects on burning rates while having no effect on average ignition-front speeds.
Keywords: Hazardous waste; Combustion characteristics; Fixed bed;

Bioaugmentation is a promising technology to clean up sites contaminated with recalcitrant chemicals. White-rot fungi have proven to be effective in the degradation of pentachlorophenol. Here, we report the bioremediation of soil contaminated with pentachlorophenol (PCP) by Anthracophyllum discolor and its impact on the soil microbial community. In this study three types of microcosms were established: fresh soil (C0), fresh soil plus wheat straw (WS0) and, fresh soil plus wheat straw inoculated with A. discolor (WSAD0). Additionally, similar treatments and a control of sterile soil spiked with PCP (C250, WS250 and WSAD250) were used to evaluate the remediation and adsorption of PCP. The PCP removal, total microbial activity, and enzymatic activities were evaluated. This study also investigated the structure of soil microbial community by denaturing gradient gel electrophoresis (DGGE), identifying some of the dominant bacterial and fungal species. The results showed that PCP was effectively degraded in soils by A. discolor and by indigenous soil microorganisms. The addition of wheat straw increased the PCP degradation and enzymatic activities. Only laccase activity was negatively affected by PCP contamination. The PCP degradation was associated with changes in microbial communities, mainly stimulation of members of bacterial phylum Proteobacteria (Xanthomonadaceae, Burkholderiaceae and Enterobacteriaceae), and fungal phylum Ascomycota and Basidiomycota. This study shows the ability of A. discolor to degrade PCP from contaminated soil, and demonstrates that agricultural residues, such as wheat straw, can be used as growth substrate by microorganisms in PCP-contaminated soil, demonstrating a great potential of autochthonous microorganisms for soil remediation.
Keywords: Anthracophyllum discolor; DGGE; Pentachlorophenol; Microbial community;

Industrial emergency planning modeling: A first step toward a robustness analysis tool by Georgios-Marios Karagiannis; Eric Piatyszek; Jean-Marie Flaus (324-334).
The purpose of this paper is to present a model-based approach to the analysis of the robustness of industrial emergency plans, established by the European Union SEVESO II Directive. Robustness is defined in terms of the capacity of the mechanism to respond to deteriorated conditions. Analysis of emergency plans has been so far based mainly upon lessons learned from past major accidents or exercises, which do not allow for an integral analysis of the response mechanism. The proposed methodology is based upon a systemic, hierarchical and generic model of an internal or external industrial emergency plan, using the FIS modeling approach. The process generally found within an industrial emergency plan is identified through the model. Potential failures are estimated through an a priori analysis of the plan model and an a posteriori analysis of lessons learned from exercises and past accidents. Assessment of the plan's functions is carried out via assessment checklists, structured via the systemic model for each of the plan's process. This approach can hence be used as a toolbox both for the assessment of existing plans and the development of industrial emergency plans.
Keywords: Industrial emergency plan; Robustness; Lessons learned; Model-based risk analysis; Risk assessment;

Adsorption of anionic dyes from aqueous solution on fly ash by Deshuai Sun; Xiaodong Zhang; Yude Wu; Xin Liu (335-342).
The adsorption behavior of two reactive dyes (Reactive Red 23 and Reactive Blue 171) and two acid dyes (Acid Black 1 and Acid Blue193) from aqueous solution on fly ash was investigated in order to identify the ability of this waste-material to remove colored textile dyes from wastewater. For this purpose a series of batch tests were carried out as a function of solution pH value, contact time, dye concentration and adsorption temperature. The experimental findings showed that the removal of four dyes on fly ash was a pH-dependent process with the maximum adsorption capacity at the initial solution pH of 7.5–8.5 for reactive dyes and 5–6 for acid dyes. Adsorption equilibriums of each anionic dye on fly ash could be reached within 60 min at respective optimum pH at 293 K. An increase in the initial dye concentration enhanced the adsorption capacity, but failed to increase the dye removal efficiency. The adsorption capacity for Reactive Red 23, Reactive Blue 171, Acid Blue193 and Acid Black 1 was found to be 2.102, 1.860, 10.937 and 10.331 mg g−1, respectively. Kinetic studies of four dyes followed the pseudo-second-order modal. Freundlich isotherm described the equilibrium data of acid dyes on fly ash better than Langmuir isotherm, but Langmuir isotherm showed better fit to the equilibrium data of reactive dyes. Different thermodynamic parameters such as the free energy, enthalpy and entropy of adsorption of the dye–fly ash systems were evaluated and it was found that the reaction was spontaneous and endothermic in nature.
Keywords: Fly ash; Adsorption; Anionic dye; Wastewater;

In this study, heterogeneous Fenton-like degradation of reactive azo dye Rhodamine 6G in water was investigated over a CuFeZSM-5 zeolite catalyst prepared by hydrothermal synthesis. At initial pH of 3.4, a color removal of 100% was achieved after a reaction time of 45 min. TOC elimination was measured to be 51.8% after 2 h of oxidation. Initial decolorization rate was described by an equation of − r A 0 = 4.56 × 10 2 e − 24.83 / R T C R6G , 0 C H 2 O 2 , 0 0.35 where R is in kJ/mol. The leaching of iron and copper cations from zeolite structure into the solution during oxidation was dependent on pH strongly. The regulation of pH from 6.5 (dye solution pH) to 3.4, increased leaching for iron from 0.7 to 0.8 mg/dm3 and for copper from 1.4 to 2.1 mg/dm3. The copper was totally leached from the catalyst during the process at pH 3.4.
Keywords: CuFeZSM-5 zeolite; FeZSM-5 zeolite; Rhodamine 6G; Heterogeneous Fenton-like degradation;

Novel biodegradable flocculanting agents based on pullulan by Luminita Ghimici; Marieta Constantin; Gheorghe Fundueanu (351-358).
New copolymers with different grafted cationic chain content and length were synthesized by graft-polymerization of (3-acrylamidopropyl)-trimethylammonium chloride onto pullulan in aqueous solution, using potassium persulfate as an initiator. Their flocculation efficiency was studied in a clay suspension as a function of the grafted chains content and length as well as of some flocculation parameters: the polycation dose, the settling time, the parent solution concentration of polycation. All the polysaccharide samples showed flocculation ability: the higher the grafted cationic chain content and length the lower the amount of pullulan derivative was required for reaching the maximum clarity degree (of about 100%). This finding together with the negative value of the zeta potential and floc size measurements, at the optimum polymer dose, point to contributions from both neutralization and bridging mechanisms for flocculation process. The residual turbidity values also varied with the settling time and the parent solution concentration of polymer.
Keywords: Graft copolymer; Pullulan; Flocculation; Turbidimetry; Zeta potential;

A flow injection (FI) cloud point extraction (CPE) method for the determination of iron and copper by flame atomic absorption spectrometer (FAAS) has been improved. The analytes were complexed with 3-amino-7-dimethylamino-2-methylphenazine (Neutral Red, NR) and octylphenoxypolyethoxyethanol (Triton X-114) was added as a surfactant. The micellar solution was heated above 50 °C and loaded through a column packed with cotton for phase separation. Then the surfactant-rich phase was eluted using 0.05 mol L−1 H2SO4 and the analytes were determined by FAAS. Chemical and flow variables influencing the instrumental and extraction conditions were optimized. Under optimized conditions for 25 mL of preconcentrated solution, the enrichment factors were 98 and 69, the limits of detection (3s) were 0.7 and 0.3 ng mL−1, the limits of quantification (10s) were 2.2 and 1.0 ng mL−1 for iron and copper, respectively. The relative standard deviation (RSD) for ten replicate measurements of 10 ng mL−1 iron and copper were 2.1% and 1.8%, respectively. The proposed method was successfully applied to determination of iron and copper in spice samples.
Keywords: Cloud point extraction; Preconcentration; Flow injection; Iron; Copper; Flame atomic absorption spectrometry; Neutral Red; Spice samples;

A useful organofunctionalized layered silicate for textile dye removal by Betina Royer; Natali F. Cardoso; Eder C. Lima; Thaís R. Macedo; Claudio Airoldi (366-374).
The octosilicate Na-RUB-18 has the ability to exchange its original sodium with cetyltrimethylammonium cations. This procedure leads to interlayer space expansion, with the aim of obtaining inorganic–organic nanostructured hybrids by chemical modification reactions. The silylating agent 3-trimethoxysilylpropylurea was attached to the inorganic layer using heterogeneous methodology. The new organofunctionalized material was characterized by elemental analysis, X-ray diffraction, 13C and 29Si nuclear magnetic resonances in the solid state, infrared spectroscopy, thermogravimetry and scanning electron microscopy. The amount of silylating agent immobilized on surface was 2.03 mmol g−1, with a basal distance of 2.43 nm. Nuclear magnetic resonance of 13C and 29Si nuclei evidenced covalent bond formation between organosilyl and silanol groups at the surface. The new synthesized nanostructured layered material was able to remove the textile dye Reactive Black 5 from aqueous solution, followed through a batchwise process. The effects of stirring time, adsorbent dosage and pH on the adsorption capacity demonstrated that 150 min is enough to reach equilibrium at 298 ± 1 K at pH 3.0. Based on error function values the data were best fitted to fractional-order kinetic models and compared to pseudo-first-order, pseudo-second-order and chemisorption kinetic models. The equilibrium data were better fitted to the Sips isotherm models.
Keywords: Layered material; RUB-18; Organofunctionalization; Adsorbent; Textile dye; Reactive Black 5 dye;

On the use of magnetic nano and microparticles for lake restoration by Inmaculada de Vicente; Azahara Merino-Martos; Luis Cruz-Pizarro; Juan de Vicente (375-381).
Innovative approaches are of outstanding importance to devise technologies for dealing with eutrophication of inland waters. This study provides a quantitative estimate showing the convenience of using magnetic nano- and micronsized particles as phosphate absorbents and their later removal from solution by high gradient magnetic separation. Two different materials are investigated (iron and magnetite) having a controlled shape and size well in the colloidal domain. Magnetite particles adsorb more phosphate (empirical saturation constant = 27.15 mg P g−1 Fe) than iron particles (empirical saturation constant = 18.83 mg P g−1 Fe) as a consequence of the different particle size (average values for particle diameters of 90.6 ± 1.2 and 805 ± 10 nm for magnetite and for iron, respectively). A protocol is established for the successful reutilization of these magnetic particles by repeated washing with NaOH and therefore, optimizing the economic cost of this technology. Magnetic particles are also surface treated with amino silane groups (APTS) to counteract magnetic and van der Waals attractive interactions and promote kinetic stability. APTS-coated iron particles experience a notable increase in phosphate maximum adsorption capacity which could be explained by a remarkable increase in electrophoretic mobility. We propose the use of APTS-coated iron particles which are less-expensive and easy to obtain as a promising technique for lake restoration.
Keywords: Phosphorus; Magnetic particles; Lake restoration; Eutrophication;

Comparison of Ca2+ and Mg2+ enhancing aerobic granulation in SBR by Lin Liu; Da-Wen Gao; Min Zhang; Yuan Fu (382-387).
Two sequencing batch reactors (SBRs) were operated to investigate the effect of Ca2+ and Mg2+ augmentation on aerobic granulation. Reactor R1 was augmented with Ca2+ at 40 mg/L, while Mg2+ was added to the reactor R2 with 40 mg/L. Results showed that the reactor R1 had a faster granulation process compared with R2, and the mature granules in R1 showed better physical characteristics. However, the mature granules in R2 had the higher production yield of polysaccharides and proteins, and aerobic granules in R2 experienced a faster substrate biodegradation. Microbial and genetic characteristics in mature granules were analyzed using polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) techniques. The results revealed that Mg2+ addition led to higher microbial diversity in mature granules. In addition, an uncultured bacterium (AB447697) was major specie in R1, and β-proteobacterium was dominant in R2. It can be concluded that Ca2+ had an important effect on physical properties of aerobic granules, while Mg2+ played a key role on biological properties during the sludge granulation.
Keywords: Ca2+; Mg2+; Aerobic granules; SBR; Microbial community structure;

Metals in molluscs and algae: A north–south Tyrrhenian Sea baseline by Marcelo Enrique Conti; Maria Grazia Finoia (388-392).
We develop a 800 km long relative baseline of metal pollution for the Tyrrhenian Sea, from the north of Naples to south of Sicily (Italy), based on spatio-temporal (1997–2004) concentrations of trace metals in marine organisms and on the bioaccumulative properties of those organisms. The study concerns sites in the gulf of Gaeta-Formia, near Naples, and three islands north, west, and south of Sicily: Ustica, Favignana and Linosa. The five metals are: cadmium, chromium, copper, lead, and zinc; the species include: Monodonta turbinata (n  = 161), Patella caerulea (n  = 244) and the algae Padina pavonica (n  = 84). We use Johnson's (1949) probabilistic method to determine the type of distribution that accounts for our data. It is a system of frequency curves that represents the transformation of the standard normal curves. We find an N–S pollution gradient in molluscs considered: the lowest metal pollution occurs around the Sicilian islands. Our method can accurately characterize marine pollution by contributing to: policy-making, coastal resources management, the assessments of environmental damages from marine accidents and other events. The method here presented is a useful tool for pollution comparisons purposes among ecosystems (i.e., risk monitoring) and it is an ideal starting point for its application on a global scale.
Keywords: Biological monitoring; Molluscs; Baseline metal levels; Johnson's method; Probabilistic method; Ecosystems’ risk monitoring;

A study of dechlorination of PCB 138, under visible light employing methylene blue (MB) and triethylamine (TEA) in acetonitrile/water has been conducted to investigate the details of the mechanism of dechlorination and to determine the efficiency of the process for this representative congener. Two other amines, N-methyldiethanolamine (MEDA) and (triethanolamine) TEOA also replaced TEA and two other solvents, methanol and ethanol replacing acetonitrile were examined for effects on reaction rates. The results show that PCB 138 can be dechlorinated efficiently in this photocatalytic reaction. Clarifying ambiguities in several previous reports, the reduced form of MB, leuco-methylene blue (LMB) was identified as responsible for the photoreaction with its excited state transferring an electron to PCBs; oxidized LMB (i.e. MB) is reduced back to LMB by the excess amine present. The reaction depends on a cycle driven by the amine as a sacrificial electron donor. MEDA proved to be the most efficient electron donor; apparently in consequence of the most favourable steady state concentration of LMB. Methanol and ethanol may be used to replace acetonitrile with little change in the efficiency of the reaction.
Keywords: Polychlorinated biphenyls; Dechlorination; Visible light; Leuco-methylene blue; Aliphatic amines;

The study reported herein indicated the stabilization mechanisms at work when copper-laden sludge is thermally treated with γ-alumina and kaolinite precursors, and evaluated the prolonged leachability of their product phases. Four copper-containing phases – copper oxide (CuO), cuprous oxide (Cu2O), copper aluminate spinel (CuAl2O4), and cuprous aluminate delafossite (CuAlO2) – were found in the thermal reactions of the investigated systems. These phases were independently synthesized for leaching by 0.1 M HCl aqueous solution, and the relative leachabilities were found to be CuAl2O4  < CuAlO2  ≪ Cu2O < CuO. The sintering condition and formation mechanism employed to stabilize copper into CuAl2O4 and CuAlO2 are extensively discussed here. With a 3 h of short sintering, it was found that CuAl2O4 could be effectively formed between 850 and 950 °C by the γ-alumina precursor. Although kaolinite had a lower incorporation capability than γ-alumina, it was found to transform a considerable amount of copper into CuAl2O4 between 950 and 1000 °C. At higher temperatures, CuAlO2 was produced only in the γ-alumina system as the occurrence of Cu2O-cristobalite solution in the kaolinite system precluded the production of CuAlO2. The hypothesis that the spinel formation mechanism has two stages was supported by the results of the changing Cu/Al mole ratio in the system, and the rate-limiting step was identified as the diffusion process in the second stage.
Keywords: Sludge; Copper; Spinel; Alumina; Kaolinite;

The adsorption of Cr(VI) was studied in batch system using fruits of Ficus glomerata as adsorbent. The effect of temperature, pH, initial Cr(VI) concentration and time was investigated. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) was used to investigate surface morphology and active functional groups present on the adsorbent surface. Thermodynamic parameters like free energy change (ΔG 0), enthalpy (ΔH 0) and entropy (ΔS 0) indicate the spontaneous, endothermic and increased randomness nature of Cr(VI) adsorption. Equilibrium data were fitted well with Langmuir isotherm at 50 °C. The magnitude of mean free energy indicates chemical nature of adsorption. The breakthrough and exhaustive capacities were found to be 5 and 23.1 mg g−1 respectively. The applicability of the adsorbent has been demonstrated by removing Cr(VI) from electroplating wastewater.
Keywords: Adsorption; Thermodynamic parameters; Mean free energy; Breakthrough capacity; Electroplating waste;

Electroenzymatic oxidation of bisphenol A (BPA) based on the hemoglobin (Hb) film in a membraneless electrochemical reactor by Tiantian Tang; Juying Hou; Shiyun Ai; Yanyan Qiu; Qiang Ma; Ruixia Han (413-418).
This paper presents a novel electroenzymatic method for the treatment of bisphenol A (BPA) in a membraneless electrochemical reactor. The electrochemical reactor was arranged with a stainless steel and an enzymatic film as anode and cathode, respectively. The enzymatic film was formed by immobilizing hemoglobin (Hb) on carbon fiber. In the membraneless electrochemical reactor, hydrogen peroxide (H2O2) was generated in situ in cathode and BPA was oxidated and removed by the combining Hb with H2O2. The experimental conditions for electrogeneration of H2O2 and electroremoval of BPA were optimized. Experimental results showed that in supplied voltage 2.4 V, pH 5.0 and oxygen flow rate 25 mL/min, the electrogeneration of H2O2 and the electroenzymatic removal of BPA were highest. Under optimal operation conditions, the removal efficiency of BPA reached 50.7% in 120 min and then kept constant when further prolonging the period of reaction. Compared with electrochemical and biochemical methods, the removal of BPA through electroenzymatic method was comparatively favorable.
Keywords: Hemoglobin; Bisphenol A; Membraneless electrochemical reactor; Electroenzymatic oxidation; Electrogeneration of hydrogen peroxide;

Removal of arsenic in coal fly ash by acid washing process using dilute H2SO4 solvent by Shunsuke Kashiwakura; Hajime Ohno; Kazuyo Matsubae-Yokoyama; Yuichi Kumagai; Hiroshi Kubo; Tetsuya Nagasaka (419-425).
Coal fly ash emitted from coal thermal power plants generally contains tens ppm of arsenic, one of the hazardous elements in coal, during combustion and their elution to soil or water has become a public concern. In this study, the acid washing process developed by the authors was applied to the removal of arsenic from coal fly ash. Laboratory- and bench-scale investigations on the dissolution behavior of arsenic from various coal fly ash samples into dilute H2SO4 were conducted. Arsenic in the coal fly ash samples were dissolved into H2SO4 solutions rapidly. However, its concentrations decreased with an increase in the pH of H2SO4 solution in some cases. The species of arsenic in the dilute H2SO4 was estimated as H3AsO4, and its anionic species was considered to adsorb with the elevation of pH under the presence of ash particle. Such adsorption behavior was enhanced under the presence of Fe ion in the solution. The sufficient removal of arsenic was achieved by controlling pH and avoiding the adsorption of arsenic on the surface of coal fly ash particles, and the elution of arsenic from coal fly ash sample was successfully below the regulation limit.
Keywords: Arsenic; Coal fly ash; Acid washing; Dissolution mechanism; Leaching test;

The effect of mixed oxidants and powdered activated carbon on the removal of natural organic matter by Jon I. Álvarez-Uriarte; Unai Iriarte-Velasco; Noemí Chimeno-Alanís; Juan R. González-Velasco (426-431).
Present paper studies the influence of electrochemically generated mixed oxidants on the physicochemical properties of natural organic matter, and especially from the disinfection by-products formation point of view. The study was carried out in a full scale water treatment plant. Results indicate that mixed oxidants favor humic to non-humic conversion of natural organic matter. Primary treatment preferentially removes the more hydrophobic fraction. This converted the non-humic fraction in an important source of disinfection by-products with a 20% contribution to the final trihalomethane formation potential (THMFPF) of the finished water. Enhanced coagulation at 40 mg l−1 of polyaluminium chloride with a moderate mixing intensity (80 rpm) and pH of 6.0 units doubled the removal efficiency of THMFPF achieved at full scale plant. However, gel permeation chromatography data revealed that low molecular weight fractions were still hardly removed. Addition of small amounts of powdered activated carbon, 50 mg l−1, allowed reduction of coagulant dose by 50% whereas removal of THMFPF was maintained or even increased. In systems where mixed oxidants are used addition of powdered activated carbon allows complementary benefits by a further reduction in the THMFPF compared to the conventional only coagulation–flocculation–settling process.
Keywords: Drinking water; Mixed oxidants; Natural organic matter; Trihalomethanes; Powdered activated carbon;

Thermal behaviors, nonisothermal decomposition reaction kinetics, thermal safety and burning rates of BTATz-CMDB propellant by Jian-Hua Yi; Feng-Qi Zhao; Bo-Zhou Wang; Qian Liu; Cheng Zhou; Rong-Zu Hu; Ying-Hui Ren; Si-Yu Xu; Kang-Zhen Xu; Xiao-Ning Ren (432-439).
The composite modified double base (CMDB) propellants (nos. RB0601 and RB0602) containing 3,6-bis (1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz) without and with the ballistic modifier were prepared and their thermal behaviors, nonisothermal decomposition reaction kinetics, thermal safety and burning rates were investigated. The results show that there are three mass-loss stages in TG curve and two exothermic peaks in DSC curve for the BTATz-CMDB propellant. The first two mass-loss stages occur in succession and the temperature ranges are near apart, and the decomposition peaks of the two stages overlap each other, inducing only one visible exothermic peak appear in DSC curve during 350–550 K. The reaction mechanisms of the main exothermal decomposition processes of RB0601 and RB0602 are all classified as chemical reaction, the mechanism functions are f(α) = (1 −  α)2, and the kinetic equations are d α / d t = 10 19.24 ( 1 − α ) 2 e − 2.32 × 10 4 / T and d α / d t = 10 20.32 ( 1 − α ) 2 e − 2.43 × 10 4 / T . The thermal safety evaluation on the BTATz-CMDB propellants was obtained. With the substitution of 26% RDX by BTATz and with the help of the ballistic modifier in the CMDB propellant formulation, the burning rate can be improved by 89.0% at 8 MPa and 47.1% at 22 MPa, the pressure exponent can be reduced to 0.353 at 14–20 MPa.
Keywords: 3,6-Bis(1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz); Composite modified double base (CMDB) propellant; Nonisothermal kinetics; Thermal safety; Burning rate;

Activated carbons were prepared from cotton stalk by one-step H3PO4 activation and used as adsorbent for the removal of lead(II). Taguchi experimental design method was used to optimize the preparation of the adsorbents. The results showed that the optimized conditions were: impregnation with a 50% (w/v) phosphoric acid solution with a mass ratio of 3:2 and activation temperature at 500 °C for 60 min with the rate of achieving the activation temperature equal to 10 °C min−1. The cotton stalk activated carbon (CSAC) prepared at these conditions have 1.43 mmol g−1 acidic surface groups and 1570 m2  g−1 BET surface area. Adsorption isotherms for lead(II) on the adsorbents were measured by conducting a series of batch adsorption experiments. The Langmuir maximum adsorption amount of lead(II) on CSAC was more than 119 mg g−1, which was superior to the ordinary commercial activated carbon (CAC) on the market. Compared with the CAC, the CSAC had a wider applicable pH range from 3.5 to 6.5 for lead(II) uptake. The final pH values at equilibrium after adsorption were lower than the initial pH value, indicating that the ion-exchange process was involved in the adsorption. This is also confirmed by the result that the increase of acidic surface groups favored the adsorption process. Thermodynamic study indicated that the adsorption was a spontaneous and endothermic process.
Keywords: Cotton stalk; Taguchi; Isotherm; Adsorption mechanism;

A novel method for amino starch preparation and its adsorption for Cu(II) and Cr(VI) by Aiqin Dong; Jie Xie; Wenmin Wang; Liping Yu; Qian Liu; Yeping Yin (448-454).
A novel method was proposed to prepare amino starch by reacting ethylenediamine with previously synthesized dialdehyde starch. Different factors affecting the preparation, i.e., ethylenediamine concentration, ethylenediamine:dialdehyde starch molar ratio, pH, duration and temperature have been studied. The modified starch was characterized by IR spectroscopy, elemental analysis, X-ray diffraction and differential scanning calorimetry. The amino starch derivatives were evaluated as adsorbents. The adsorption activity for heavy metals such as Cu(II) and Cr(VI) by crosslinked amino starch was studied in terms of adsorption amount, kinetics and isotherm; and adsorbent reuse were also studied. Adsorption processes for Cu(II) and Cr(VI) on crosslinked amino starch fit a Langmuir isotherm, and adsorption for Cu(II) and Cr(VI) from aqueous solution was endothermic reactions. Crosslinked amino starch was very effective for the adsorption of Cu(II) and Cr(VI), and efficient in capacity, recycled.
Keywords: Adsorption; Preparation; Heavy metal ions; Starch;

Effects of IDSA, EDDS and EDTA on heavy metals accumulation in hydroponically grown maize (Zea mays, L.) by Zhongqiu Zhao; Meizhu Xi; Guangyu Jiang; Xiaona Liu; Zhongke Bai; Yizong Huang (455-459).
Heavy metals contamination of soil is a widespread global problem. Chelant assisted phytoextraction has been proposed to improve the efficiency of phytoextraction which involves three subsequent levels: transfer of metals from the bulk soil to the root surfaces, uptake into the roots and translocation to the shoots. However, most studies focused on the first level. A hydroponic experiment, which addresses the latter two levels, was conducted to study the effects of EDTA, EDDS and IDSA on the uptake and the distribution of Pb, Zn, Cu and Cd in the apoplast and the symplast of roots of maize (Zea mays, L.). The concentrations of the metals (with exception of Zn) in the shoots were increased significantly by addition of all the chelants. EDTA was most effective for Pb uptake and IDSA was interestingly most effective for Cd uptake. Pb in the roots with EDTA was mostly distributed in the apoplast, while Zn, especially with IDSA, was mostly located in the symplast. The results indicated that, the capacity of chelant to enhance the nonselective apoplastic transport of metal may be most important for chelant enhanced phytoextraction.
Keywords: Chelants; Heavy metals; Uptake; Distribution; Apoplast; Symplast;

Effects of Ni2+ on the characteristics of bulking activated sludge by Ling Wang; Yan Liu; Jia Li; Xiang Liu; Ruihua Dai; Yun Zhang; Siying Zhang; Jingrui Li (460-467).
This study investigated effects of the continuous addition of a high-concentration of Ni2+ on the characteristics of bulking activated sludge as well as on the variety and recovery of their ability removing organic pollutants and ammonia in a sequencing batch reactor (SBR). To the knowledge of the authors, this is the first study to examine the changes in quantity and composition of the extracellular polymeric substances (EPS) in bulking activated sludge before and after the addition of a high-concentration of Ni2+. The correlation between these changes and the sludge characteristics was also investigated. The results showed that after a 40-day acclimation to the addition of 60 mg/L Ni2+, the ability to remove organic pollutants was recovered; but the ability to remove ammonia was not. The addition of Ni2+ made a great change in the quantity and composition of the EPS in bulking sludge, including both exterior soluble EPS (EPSS) and interior bound EPS (EPSb), showing a slight increase followed by a large decrease before reaching a steady state. The difference between the change in the amounts of EPSS and EPSb was not significant. However, among the component fractions, the change in protein content was obvious than that of polysaccharide and humic acid.
Keywords: Ni2+; Activated sludge; Bulking; Extracellular polymeric substances (EPS); Ammonia–nitrogen;

Carboxylate-functionalized cellulose can be used as a low cost but effective biosorbent for heavy metals remediation. In this study, it was simply fabricated from wood cellulose and succinic anhydride via solvent-free mechanochemistry in the absence of catalyst at ambient temperature through pan-milling. Fourier transform infrared spectra (FT-IR) confirmed the realization of mechanochemical esterification of cellulose. Reaction kinetics study showed that this solid-state mechanochemical reaction was governed by “slow followed by fast” kinetics model. The reaction sites were mainly at the new surface of cellulose powder where hydrogen bondings in cellulose were broken up and hydroxyl groups were activated due to the fairly strong forces imposed by the pan-mill. X-ray photoelectron spectroscopy (XPS) indicated that the mechanochemical succinylation of cellulose occurred even in a short milling time. The exponential increment of surface area of cellulose during pan-milling was correlated to the increasing substitution degree. Preliminary adsorption studies showed that the modified cellulose possessed excellent adsorption capacity towards Pb2+, with lead ion uptake value of 422 mg/g and 84.4% metal removal from a 500 mg/g Pb2+ solution, significantly higher than those values for unmodified cellulose.
Keywords: Cellulose; Mechanochemistry; Surface modification; Biosorbent;

Adsorption capacity of Cr(VI) onto chitosan coated with poly 3-methyl thiophene synthesized chemically was investigated in a batch system by considering the effects of various parameters like contact time, initial concentration, pH and temperature. Cr(VI) removal is pH dependent and found to be maximum at pH 2.0. Increases in adsorption capacity with increase in temperature indicate that the adsorption reaction is endothermic. Based on this study, the thermodynamic parameters like standard Gibb's free energy (ΔG°), standard enthalpy (ΔH°) and standard entropy (ΔS°) were evaluated. Adsorption kinetics of Cr(VI) ions onto chitosan coated with poly 3-methyl thiophene were analyzed by pseudo-first-order and pseudo-second-order models. The Langmuir, Freundlich and Temkin isotherms were used to describe the adsorption equilibrium studies of chitosan coated with poly 3-methyl thiophene at different temperatures. Langmuir isotherm shows better fit than Freundlich and Temkin isotherms in the temperature range studied. The results show that the chitosan coated with poly 3-methyl thiophene can be efficiently used for the treatment of wastewaters containing chromium as a low cost alternative compared to commercial activated carbon and other adsorbents reported. In order to find out the possibility of regeneration and reuse of exhausted adsorbent, desorption studies were also performed.
Keywords: Chromium(VI) removal; Poly 3-methyl thiophene; Chitosan;

Potential of Taraxacum mongolicum Hand-Mazz for accelerating phytoextraction of cadmium in combination with eco-friendly amendments by Shuhe Wei; Shanshan Wang; Qixing Zhou; Jie Zhan; Lihui Ma; Zhijie Wu; Tieheng Sun; M.N.V. Prasad (480-484).
Phytoextraction and phytostabilization are well-established sub-processes of phytoremediation that are being followed for in situ remediation of soils contaminated with toxic metals. Taraxacum mongolicum Hand-Mazz, a newly reported Cd accumulator has shown considerable potential for phytoextracting Cd. This paper investigated the effects of urea and chicken manure on T. mongolicum phytoextracting Cd from soil using pot culture experiments. The results showed that urea application did not affect the Cd concentrations in root, leaf, inflorescence and shoot of T. mongolicum, but chicken manure significantly decreased them (p  < 0.05) by 23.5%, 31.5%, 24.8% and 30.4% owing to decreased extractable Cd. Urea and chicken manure significantly increased (p  < 0.05) the phytoextraction capacities (μg pot−1) of T. mongolicum to Cd by 3–5-fold due to the increase in shoot biomass (increased 4–7 folds). Further, addition of urea and chicken manure increased organic matter, nitrogen, phosphorus and potassium, the microorganism count, urease and phosphatase activities of soil indicating their eco-friendly function. Urea is ideal for optimizing phytoextraction of T. mongolicum to Cd, while chicken manure is appropriate for phytostabilization.
Keywords: Urea; Chicken manure; Phytoremediation; Taraxacum mongolicum Hand-Mazz; Cd (Cadmium);

Novel spectrophotometric method for the determination of aluminum in soda drinks packed in cans and plastic bottles by Barbara Bruna A. Francisco; Luiz Fernando S. Caldas; Daniel M. Brum; Ricardo J. Cassella (485-490).
In the present work, a new spectrophotometric method was developed for the determination of aluminum in soda drinks packed in different materials. Reaction among Al(III), phenylfluorone (PF) and cetylpyridinium chloride (CPC) in slightly alkaline medium was explored for this purpose. The method was optimized regarding to its chemical parameters in order to establish better conditions in terms of sensitivity and selectivity. The results obtained showed that the concentration of CPC presented remarkable influence on the sensitivity and acted as a sensitizer for the studied system. The possible interferences of some metallic cations were evaluated and the cations Cu(II), Mn(II), and Zn(II) presented noticed interference on the Al(III) signal. So, their interference was eliminated by using EDTA with minimum loss of sensitivity. The results obtained in the determination of total aluminum in soda drinks by the developed methodology were not statistically different from those obtained by electrothermal atomic absorption spectrometry. In the optimized conditions the method presented a linear range of 5–100 μg L−1. The limits of detection and quantification were 0.81 and 2.7 μg L−1, respectively. The methodology was successfully applied in the determination of aluminum in 10 samples of soda drinks packed in cans and plastic bottles.
Keywords: Aluminum; Spectrophotometry; Soda drinks;

A simple and effective speciation and preconcentration method based on hollow fiber liquid phase microextraction (HF-LPME) was developed for simultaneous separation of trace inorganic tellurium and selenium in environmental samples prior to electrothermal atomic absorption spectroscopy (ETAAS) determination. The method involves the selective extraction of the Te (IV) and Se (IV) species by HF-LPME with the use of ammonium pyrrolidinecarbodithioate (APDC) as the chelating agent. The complex compounds were extracted into 10 μL of toluene and the solutions were injected into a graphite furnace for the determination of Te (IV) and Se (IV). To determine the total tellurium and selenium in the samples, first Te (VI) and Se (VI) were reduced to Te (IV) and Se (IV), and then the microextraction method was performed. The experimental parameters of HF-LPME were optimized using a central composite design after a 2 n−1 fractional factorial experimental design. Under optimum conditions, enrichment factors of up to 520 and 480 were achieved for Te (IV) and Se (IV), respectively. The detection limits were 4 ng L−1 with 3.5% RSD (n  = 5, c  = 2.0 μg L−1) for Te (IV) and 5 ng L−1 with 3.1% RSD for Se (IV). The applicability of the developed technique was evaluated by application to spiked, environmental water and soil samples.
Keywords: Speciation; Hollow fiber; Central composite design; Environmental samples;

The effects of arbuscular mycorrhizal (AM) fungi and phosphate rock on the phytorextraction efficiency of a hyperaccumulator (Pteris vittata) and a non-hyperaccumulator (Cynodon dactylon) plant were studied. Both seedlings were planted in As contaminated soil under different treatments {(1) control (contaminated soil only), (2) indigenous mycorrhizas (IM), (3) mixed AM inoculum [indigenous mycorrhiza + Glomus mosseae (IM/Gm)] and (4) IM/Gm + phosphate rock (P rock)} with varying intensities (40%, 70% and 100%) of water moisture content (WMC). Significant As reduction in soil (23.8% of soil As reduction), increase in plant biomass (17.8 g/pot) and As accumulation (2054 mg/kg DW) were observed for P. vittata treated with IM/Gm + PR at 100% WMC level. The overall results indicated that the synergistic effect of mycorrhiza and P rock affected As subcellular distribution of the hyperaccumulator and thereby altered its As removal efficiency under well-watered conditions.
Keywords: Phytoextraction; Arsenic; Hyperaccumulator; Mycorrhizae; Phosphate;

Degradation of iopromide by combined UV irradiation and peroxydisulfate by Ting W. Chan; Nigel J.D. Graham; Wei Chu (508-513).
The aqueous degradation of iopromide, an iodinated X-ray contrast media (ICM) compound, by the combination of UV254 irradiation and potassium peroxydisulfate (K2S2O8) has been studied in laboratory scale experiments. The influence of various parameters on the performance of the treatment process has been considered, namely the UV irradiation light intensity, the initial concentrations of iopromide and peroxydisulfate, and the initial solution pH. Iopromide degradation increased with UV light intensity and peroxydisulfate concentration, but decreased with initial pH. Under specific conditions complete removal of iopromide was achieved within 30 min, and near-complete mineralisation (loss of solution TOC) within 80 min. Degradation was believed to be caused by a combination of direct photolysis, sulphate radical attack, and, to a minor degree, direct oxidation by peroxydisulfate. Approximate values for the reaction rate constants have been determined and found to be equal to 1–2 × 104  M−1  s−1 for sulfate radicals, and 1–2 M−2  s−1 for S2O8 2−. Overall compound degradation was observed to follow first-order kinetics where the rate constant decreased with initial solution pH. During the reaction, the solution pH decreased as a consequence of sulfate radical scavenging.
Keywords: Iodinated X-ray contrast media; Iopromide; UV irradiation; Peroxydisulfate; AOPs;

Manganese and limestone interactions during mine water treatment by A.M. Silva; F.L.S. Cruz; R.M.F. Lima; M.C. Teixeira; V.A. Leão (514-520).
Manganese removal from mining-affected waters is an important challenge for the mining industry. Addressed herein is this issue in both batch and continuous conditions. Batch experiments were carried out with synthetic solutions, at 23 ± 2 °C, initial pH 5.5 and 8.3 g limestone/L. Similarly, continuous tests were performed with a 16.5 mg/L Mn2+ mine water, at 23 °C, initial pH 8.0 and 20.8 g limestone/L. Calcite limestone gave the best results and its fine grinding proved to the most effective parameter for manganese removal. In either synthetic solutions or industrial effluents, the final manganese concentration was below 1 mg/L. A change in limestone surface zeta potential is observed after manganese removal and manganese carbonate formation was suggested by IR spectroscopy. The conclusion is that limestone can remove manganese from industrial effluents for values that comply with environmental regulations.
Keywords: Manganese; Limestone; Mine waters; ATR-IR; Acid mine drainage;

The role of hydroxyl radical is investigated in electrochemical oxidation of organic contaminants with naphthalene as a model compound. The strategy employed was competitive kinetic for hydroxyl radical between naphthalene and other hydroxyl scavengers if the hydroxyl radical is produced in situ at the anode by the electrolysis of water. Methanol, d3-methanol, acetone and d6-acetone were used as competitors for hydroxyl radical and their molar concentrations were calculated based on their reaction constants with hydroxyl radical. The hydroxyl radical was not responsible for naphthalene loss in these experiments. The first order reaction rate constants in the batch experiments containing only naphthalene, 2 mM of each of acetone and d6-acetone were 0.093, 0.094 and 0.118 h−1, respectively. Higher concentrations (4 mM) acetone and d6-acetone did not affect naphthalene degradation. Rate constants using methanol and d6-methanol as competitors for hydroxyl radical in batch degradations test were 0.128 and 0.099 h−1, respectively. Based on the naphthalene degradation trends and reaction rate constants, it was concluded that, under the given set of conditions, hydroxyl radical was not responsible for naphthalene degradation during electrolytic degradation tests. This research suggests that the role of hydroxyl radical should be considered very carefully in modeling such indirect electrolytic oxidation processes.
Keywords: Naphthalene; Competitors; Scavengers; Anodic oxidation; Hydroxyl radical;

Scorodite encapsulation by controlled deposition of aluminum phosphate coatings by F. Lagno; S.D.F. Rocha; S. Chryssoulis; G.P. Demopoulos (526-534).
A new stabilization process for scorodite (FeAsO4·2H2O) solids based on the concept of encapsulation by controlled deposition of mineral coatings immune to pH or redox potential variations is described. The stability of the encapsulated scorodite with aluminum phosphates under simulated anoxic and oxic environments is demonstrated. Encapsulation experiments were carried out at 95 °C using 50 g/L scorodite in acidic sulphate solution containing 0.16 mol/L of P(V) with Al(III) to P(V) molar ratio of 1 and precipitation pH of 1.7. The encapsulated particles were characterised by XRD, SEM, TOF-SIMS and TOF-LIMS. The coating was crystalline AlPO4·1.5H2O ranging in thickness from 2.5 to 3.5 μm. Encapsulation of scorodite particles with hydrated aluminum phosphate appears to be effective in controlling/suppressing the release of arsenic under both oxic and anoxic conditions by more than one order of magnitude.
Keywords: Arsenic; Scorodite; Encapsulation; Stabilization; Supersaturation control; Aluminum phosphate;

Adsorptive removal of methyl orange from aqueous solution with metal-organic frameworks, porous chromium-benzenedicarboxylates by Enamul Haque; Ji Eun Lee; In Tae Jang; Young Kyu Hwang; Jong-San Chang; Jonggeon Jegal; Sung Hwa Jhung (535-542).
Two typical highly porous metal-organic framework (MOF) materials based on chromium-benzenedicarboxylates (Cr-BDC) obtained from Material of Institute Lavoisier with special structure of MIL-101 and MIL-53 have been used for the adsorptive removal of methyl orange (MO), a harmful anionic dye, from aqueous solutions. The adsorption capacity and adsorption kinetic constant of MIL-101 are greater than those of MIL-53, showing the importance of porosity and pore size for the adsorption. The performance of MIL-101 improves with modification: the adsorption capacity and kinetic constant are in the order of MIL-101 < ethylenediamine-grafted MIL-101 < protonated ethylenediamine-grafted MIL-101 (even though the porosity and pore size are slightly decreased with grafting and further protonation). The adsorption capacity of protonated ethylenediamine-grafted MIL-101 decreases with increasing the pH of an aqueous MO solution. These results suggest that the adsorption of MO on the MOF is at least partly due to the electrostatic interaction between anionic MO and a cationic adsorbent. Adsorption of MO at various temperatures shows that the adsorption is a spontaneous and endothermic process and that the entropy increases (the driving force of the adsorption) with MO adsorption. The adsorbent MIL-101s are re-usable after sonification in water. Based on this study, MOFs can be suggested as potential re-usable adsorbents to remove anionic dyes because of their high porosity, facile modification and ready re-activation.
Keywords: Porous chromium-benzenedicarboxylates; MOFs; Methyl orange; Dye; Adsorption; Removal;

Investigation of 4-year-old stabilised/solidified and accelerated carbonated contaminated soil by A. Antemir; C.D. Hills; P.J. Carey; M-C. Magnié; A. Polettini (543-555).
The investigation of the pilot-scale application of two different stabilisation/solidification (S/S) techniques was carried out at a former fireworks and low explosives manufacturing site in SE England. Cores and granular samples were recovered from uncovered accelerated carbonated (ACT) and cement-treated soils (S/S) after 4 years to evaluate field-performance with time. Samples were prepared for microstructural examination and leaching testing. The results indicated that the cement-treated soil was progressively carbonated over time, whereas the mineralogy of the carbonated soil remained essentially unchanged. Distinct microstructures were developed in the two soils. Although Pb, Zn and Cu leached less from the carbonated soil, these metals were adequately immobilised by both treatments. Geochemical modeling of pH-dependent leaching data suggested that the retention of trace metals resulted from different immobilisation mechanisms operating in the two soils examined.
Keywords: Stabilisation/solidification; Accelerated carbonation; Contaminated soil; Microstructure; Mineralogy; Metal leaching;

Phosphorus fractions and matrix-bound phosphine in coastal surface sediments of the Southwest Yellow Sea by Yuning Hong; Jinju Geng; Song Qiao; Yongzhan Zhang; Lili Ding; Xiaorong Wang; Hongqiang Ren (556-564).
This paper characterizes the distribution of phosphorus fractions and matrix-bound phosphine (MBP) in coastal surface sediments of the Southwest Yellow Sea from 2006 to 2007. Total phosphorus (TP), inorganic phosphorus (IP) and organic phosphorus (OP) concentrations (mg kg−1) range from 278 ± 3 to 768 ± 15, 160 ± 1 to 653 ± 27, and 3.42 ± 0.05 to 267 ± 22, respectively. MBP is a small portion of TP with values of 0.69 ± 0.06 to 179 ± 29 ng kg−1. Phosphorus fractions and MBP are influenced strongly by riverine input and hydrodynamic conditions. High TP and MBP are found in the old Yellow River mouth and the Yangtze River mouth. OP and MBP are strongly negatively correlated to mean particle size. Significant positive correlations are found between MBP and IP and OM, suggesting that MBP production may be the microbially intermediated transformation of IP.
Keywords: Phosphorus fractions; MBP; Coastal zone; Sediments; Southwest Yellow Sea;

Risk assessment of trace elements in sediments: The case of the estuary of the Nerbioi–Ibaizabal River (Basque Country) by Silvia Fdez-Ortiz de Vallejuelo; Gorka Arana; Alberto de Diego; Juan Manuel Madariaga (565-573).
Long term (January 2005–January 2008) monitoring of sediments was used to investigate metal pollution in the estuary of the Nerbioi–Ibaizabal River (Bilbao, Basque Country). Sediments were collected from eight representative locations of the estuary approximately every three months. The concentration of fourteen elements was measured in sediment extracts. Different graphical representations of the data set, simple statistical methods and sediment quality guidelines were combined to investigate trends in space and time, identify pollution sources, and assess sediment quality from a toxicological point of view. In general terms, the main trend reveals a significant fall in metal concentration over the period investigated. There are still certain points of the estuary with relatively high concentration of toxic metals, but the toxicological approach suggests that the risk for living organisms is not important.
Keywords: Estuarine sediments; Trace elements; Risk assessment; Nerbioi–Ibaizabal; Bilbao;

Selective adsorption behavior of phosphate onto aluminum hydroxide gel by Naohito Kawasaki; Fumihiko Ogata; Hisato Tominaga (574-579).
The specific surface area and X-ray diffraction patterns for an aluminum hydroxide gel (AHG) calcined at 300–1150 °C, the number of surface hydroxyl groups in the AHG, and the adsorption isotherms of phosphate on AHG were measured in order to develop a phosphate recovery agent. AHG was transformed into γ- and α-alumina by the calcinations treatment. The amount of phosphate adsorbed onto AHG increases at calcining temperatures of 300–700 °C and decreases above a calcining temperature of 800 °C. It was found that AHG selectively adsorbs phosphate ions, but not other anions, and shows the highest adsorption capacity at pH 4–6. Further, the alkali resistance of AHG increased with calcination, and more than 80% of the phosphate adsorbed with an NaOH aqueous solution underwent desorption. The addition of colloidal alumina and colloidal silica resulted in the formation of granules of 500–840 μm size. The amount of phosphate adsorbed onto AHG after granulation was similar to that before granulation. Thus, the phosphate absorption capacity of AHG did not decrease after granulation suggesting that AHG can be used as a phosphate adsorbent.
Keywords: Adsorption isotherms; Ion–solid interactions; Aluminum hydroxide gel; Phosphate;

Destruction of inorganic municipal solid waste incinerator fly ash in a DC arc plasma furnace by Peng Zhao; Guohua Ni; Yiman Jiang; Longwei Chen; Mingzhou Chen; Yuedong Meng (580-585).
Due to the toxicity of dioxins, furans and heavy metals, there is a growing environmental concern on municipal solid waste incinerator (MSWI) fly ash in China. The purpose of this study is directed towards the volume-reduction of fly ash without any additive by thermal plasma and recycling of vitrified slag. This process uses extremely high-temperature in an oxygen-starved environment to completely decompose complex waste into very simple molecules. For developing the proper plasma processes to treat MSWI fly ash, a new crucible-type plasma furnace was built. The melting process metamorphosed fly ash to granulated slag that was less than 1/3 of the volume of the fly ash, and about 64% of the weight of the fly ash. The safety of the vitrified slag was tested. The properties of the slag were affected by the differences in the cooling methods. Water-cooled and composite-cooled slag showed more excellent resistance against the leaching of heavy metals and can be utilized as building material without toxicity problems.
Keywords: Thermal plasma; Vitrification; Fly ash; DC arc; Slag;

Templated preparation of porous magnetic microspheres and their application in removal of cationic dyes from wastewater by Qingquan Liu; Li Wang; Anguo Xiao; Jingming Gao; Wenbing Ding; Haojie Yu; Jia Huo; Mårten Ericson (586-592).
Porous magnetic microspheres with large particle size (350–450 μm) were prepared with sulfonated macroporous polydivinylbenzene as a template. The preparation process included ferrous ion exchange and following oxidation by hydrogen peroxide. The results showed that the weight fraction of magnetic nanoparticles exceeded 20 wt% in microspheres after the preparation process was repeated three times. X-ray diffraction profiles indicated that the crystalline phase of as-formed magnetic nanoparticles was magnetite (Fe3O4). TEM images revealed rod-like magnetite crystal after the first oxidation cycle, however, the crystal morphologies were transferred into random shape after more oxidation cycles. The applicability of porous magnetic microspheres for removal of cationic dyes from water was also explored. The results exhibited that basic fuchsin and methyl violet could be quickly removed from water with high efficiency. More importantly, the magnetic microspheres could be easily regenerated and repeatedly employed for wastewater treatment. Therefore, a novel methodology was provided for fast removal cationic dyes from wastewater.
Keywords: Magnetic microspheres; Cationic dye; Removal; Regeneration;

The objective of this study was the synthesis of α′L-C2S (Ca2SiO4) belite cement, starting from fly-ash of system CaO–SiO2–Al2O3–SO3, and using the hydrothermal method in alkaline solution. The lime deficit in these ashes was compensated by the addition of slaked lime from lime bagging workshops. The hydrothermal treatment of the mixture was carried out in demineralized water, NaOH or KOH solution, continually stirred at a temperature below 100 °C and atmospheric pressure. The dehydration and calcination of the mixtures at temperatures between 800 and 1100 °C allowed α′L-C2S-rich cement to be obtained. The optimization of the synthesis parameters (temperature and time of stirring, pH of solution, temperature and duration of mixture burning) was also studied. The phase formation during various synthesis stages was studied by X-ray diffraction (XRD). Other techniques, such as SEM and EDX, were used to characterize the cement minerals. The results obtained showed that these ashes could form belite cement composed of only one dicalcium silicate phase (α′L-C2S).
Keywords: Clinker; Belite; Fly-ash; Hydrothermal treatment; Eco-cement;

Decolorization of Acid Red GR by a newly isolated biphenyl-degrading bacterium, Dyella ginsengisoli LA-4 was presented in this paper. The optimal decolorization conditions were determined by response surface methodology (RSM) based on the rotatable central composite design. The results indicated that strain LA-4 possessed the highest decolorizing activity under anaerobic conditions with inoculation amount 6.49%, pH 7.06 and temperature 29 °C. Some ions such as Cu2+, Zn2+ could inhibit the decolorization, whereas 1 mmol/L of Mg2+, Ca2+, Co2+, Fe3+, Ni2+ and Mn2+ had no effects on the process. It was demonstrated that anthraquinone as a redox mediator could significantly accelerate the reduction process of azo dyes.
Keywords: Azo dyes; Decolorization; Dyella ginsengisoli; Response surface methodology; Redox mediator;

A numerical study of the evolution of the blast wave shape in tunnels by Adel M. Benselama; Mame J.-P. William-Louis; François Monnoyer; Christophe Proust (609-616).
When the explosion of condensed materials occurs in a tunnel, the subsequent blast wave reveals two patterns. The region close to the explosive charge exhibits a free-field overpressure decay pattern and the region far from the explosion, which undergoes much less overpressure decay, exhibits a quasi-one-dimensional pattern. Well-known overpressure decay laws that are applicable in each region already exist. In order to assess the validity range of each of these laws, the blast wave due an explosion inside a typical confined geometry is examined in order to determine the position of the transition zone from the free pattern to the one-dimensional pattern. To this end, the detonation of different quantities of explosive charges was simulated inside a tunnel with a constant cross-sectional area, and the wave aspect was determined for each region. This paper proposes a correlation law that defines the transition distance according to the explosive charge’s weight and material and the geometry of the propagating domain. The validity of the proposed correlation law is corroborated by experimental results. In the authors’ opinion, this law may be helpful for rapidly and efficiently drawing up the blast wave damage map.
Keywords: Damage assessment for explosions; Three-dimensional simulation; Blast wave; Confined domain;

Relevance of an electrochemical process prior to a biological treatment for the removal of an organophosphorous pesticide, phosmet by Nara Alonso Salles; Florence Fourcade; Florence Geneste; Didier Floner; Abdeltif Amrane (617-623).
The aim of this study was to examine the feasibility of coupling an electrochemical pre-treatment with a biological step in order to degrade phosmet, an organophosphorous pesticide. Preliminary biodegradation experiments showed that the target molecule was not assimilated by activated sludge. The pre-treatment consisted of potentiostatic electrolysis (−1.3 V/SCE) in a flow cell. After only one pass (1 mL min−1), cyclic voltammetry with a vitreous carbon electrode showed a total phosmet reduction in neutral medium confirmed by thin layer chromatography, which also highlighted the presence of several by-products. H NMR spectra of the main by-product showed the absence of the aromatic ring, only the phosphorus part of phosmet has been identified and phosmet-oxon, a very toxic derivative, was not formed. Lower toxicity and higher biodegradability characterized the electrolyzed solution, EC50 value increased from 7% to 58% and BOD5 value increased from 4 to 9 mg O2  L−1 after electrolysis leading to an increase of the BOD5 on COD ratio from 0.19 to 0.42 (limit of biodegradability, 0.4). These encouraging results were confirmed during activated sludge culture since an almost total mineralization of the electrolyzed solution was recorded (97%), confirming the feasibility of the proposed coupled process.
Keywords: Integrated process; Electrochemical pre-treatment; Biological treatment; Pesticide degradation; Phosmet;

Adsorption of hexavalent chromium on cationic cross-linked starches of different botanic origins by Rima Klimaviciute; Joana Bendoraitiene; Ramune Rutkaite; Algirdas Zemaitaitis (624-632).
The influence of origin of native starch used to obtain cationic cross-linked starch (CCS) on the adsorption of Cr(VI) onto CCS has been investigated. CCS granule size is influenced by the botanic source of native starch. The equilibrium adsorption of Cr(VI) onto CCS was described by the Langmuir, Freundlich, Dubinin–Radushkevich and Temkin models. The more equal the adsorption energy of the quaternary ammonium groups in CCS granule as indicated by low value of change of Temkin adsorption energy ΔE T the greater amount of Cr(VI) was adsorbed onto CCS. The value of ΔE T decreased and sorption capacity of CCS increased with the decrease of CCS granule size and with the increase of number of amorphous regions in CCS granules. The affinity of dichromate anions increases and adsorption proceeds more spontaneously when Cr(VI) is adsorbed onto more amorphous CCS. Adsorption process of Cr(VI) onto such CCS is more exothermic and order of system undergoes major changes during adsorption. After the adsorption on CCS Cr(VI) could be regenerated by incineration at temperature of 800 °C.
Keywords: Cationic cross-linked starch; Hexavalent chromium; Adsorption;

Ruthenium versus platinum on cerium materials in wet air oxidation of acetic acid by J. Gaálová; J. Barbier; S. Rossignol (633-639).
This study was a comparison between Ru-catalysts and similar, previously investigated, Pt-catalysts. In this paper, ruthenium catalysts for catalytic wet air oxidation are prepared, characterized and tested. Both catalysts were supported on commercial CeO2 as well as mixed oxide Zr0.1(Ce0.75Pr0.25)0.9O2. The catalysts were characterized by measuring the oxygen storage capacities (OSC), BET, XRD, FTIR and chemisorption of hydrogen. In addition, the effect of sintering (treatments under H2) was compared with both of the catalysts. The comparison of the results showed that initial intrinsic activity of ruthenium is not significantly influenced by the type of the support, which is contrast to platinum. Furthermore, the particle size of Ru had an important effect on CWAO activity: the higher the particle size, the better the activity. This was different with Pt-catalysts, where the optimal particle size was smaller, having about 15% of metal dispersion.
Keywords: Ruthenium; CWAO; Ceria; mixed oxide; Deactivation;

A detailed investigation was conducted to study the heavy metal concentrations in roadside soils of Beijing. The concentrations of Cd, Cu, Pb and Zn showed a decreasing trend with increasing distance from the road while such trend was not identified in As, Cr and Ni. In addition, the concentrations of Cd, Cu, Pb and Zn significantly positively correlated with black carbon (BC) and TOC (p < 0.01). The soil samples from West 2nd Ring Road with the highest traffic volume had the highest heavy metal concentrations of the 10 roads, and Pb concentration was significantly positively correlated with traffic volumes (p  < 0.05). According to the soil guideline values of China, Cd was considered to have considerable contamination in roadside soils, while Cu, Pb and Zn less, but As, Ni, Cr none. The concentrations of heavy metals in roadside soils of Beijing were considered medium or low in comparison with those in other cities; this may be due to the windy and dry climate in Beijing. The heavy metals could move with wind along the wind direction and the soil samples had higher heavy metal concentrations at the downwind direction.
Keywords: Urban traffic; Roadside soils; Heavy metals; Beijing;

The purpose of this study was to determine the variation of concentrations and distribution of PAHs in the sediments of the Gela coastal area (Italy) caused by the construction of an underwater pipeline connecting Libya to Sicilian coast. The receiving terminal of offshore pipeline, crossing the Mediterranean Sea, 516 Km long, up to 1127 meters deep, is located in Gela (Sicily, Italy). No bibliographic data regarding hydrocarbons are available for this area. In this paper we report the results of analysis on the water and organic along PAHs.The total concentrations of 16 PAHs in the sediments, analyzed during five surveys, ranged from 2.4 to 434 μg/kg of dry weight. The highest concentrations of total PAHs were found in sediments during the monitoring campaign immediately following the laying of the pipeline. A progressive decrease during the subsequent surveys was observed: The found concentrations was in the direction of restoring the initial situation. Highest levels of PAHs concentration have been often observed in sample stations endowed with highest organic matter content.
Keywords: PAHs; Pipeline; Gela; Sicily;

During the ozonation of tetracycline (TC) in aqueous media at pHs 2.2 and 7.0, the effects of pH variations, protonation and dissociation of functional groups and variation in free radical exposure were investigated to elucidate the transformation pathway. Liquid chromatography–triple quadrupole mass spectrometry detected around 15 ozonation products, and uncovered their production and subsequent degradation patterns. During ozonation at pH 2.2, the TC degradation pathway was proposed on the basis of the structure, ozonation chemistry and mass spectrometry data of TC. Ozonation of TC at the C11a–C12 and C2–C3 double bonds, aromatic ring and amino group generated products of m/z 461, 477, 509 and 416, respectively. Further ozonation at the above mentioned sites gave products of m/z 432, 480, 448, 525 and 496. The removal of TOC reached a maximum of ≈40% after 2 h of ozonation, while TC was completely removed within 4–6 min at both pHs. The low TOC removal efficiency might be due to the generation of recalcitrant products and the low ozone supply for high TC concentration. Ozonation decreased the acute toxicity of TC faster at pH 7.0 than pH 2.2, but the maximum decrease was only about 40% at both pHs after 2 h of ozonation. In this study, attempts were made to understand the correlation between the transformation products, pathway, acute toxicity and quantity of residual organics in solution. Overall, ozonation was found to be a promising process for removing TC and the products initially generated.
Keywords: Ozonation; Tetracycline; Degradation products; Degradation pathway; Toxicity assay; Vibrio fischeri;

This study investigated the biosorption of Reactive Red 195 (RR 195), an azo dye, from aqueous solution by using cone biomass of Pinus sylvestris Linneo. To this end, pH, initial dye concentration, biomass dosage and contact time were studied in a batch biosorption system. Maximum pH for efficient RR 195 biosorption was found to be 1.0 and the initial RR 195 concentration increased with decreasing percentage removal. Biosorption capacity increased from 6.69 mg/g at 20 °C to 7.38 mg/g at 50 °C for 200 mg/L dye concentration. Kinetics of the interactions was tested by pseudo-first-order and pseudo-second-order kinetics, the Elovich equation and intraparticle diffusion mechanism. Pseudo-second-order kinetic model provided a better correlation for the experimental data studied in comparison to the pseudo-first-order kinetic model and intraparticle diffusion mechanism. Moreover, the Elovich equation also showed a good fit to the experimental data. Freundlich and Langmuir adsorption isotherms were used for the mathematical description of the biosorption equilibrium data. The activation energy of biosorption (Ea) was found to be 8.904 kJ/mol by using the Arrhenius equation. Using the thermodynamic equilibrium coefficients obtained at different temperatures, the study also evaluated the thermodynamic constants of biosorption (ΔG o , ΔH o and ΔS). The results indicate that cone biomass can be used as an effective and low-cost biosorbent to remove reactive dyes from aqueous solution.
Keywords: Elovich equation; Intraparticle diffusion; Kinetic; Pinus sylvestris L.; Reactive Red 195; Thermodynamic;

In order to explore a practical approach to the remediation of the cadmium (Cd)-contaminated soil in the lower reaches of the Yangtze River, we evaluated the effects of a local willow (Salix  ×  aureo-pendula CL ‘J1011’) of absorbing, accumulating, and translocating Cd; and assessed the potential of chelator ethylenediaminetetraacetic acid (EDTA) in combination with ethyl lactate for enhancing the efficiency of the willow in removing Cd in two water-culture growth chamber trials and a field one. The willow showed a high tolerance to Cd in growth chamber trial 1 where the Cd concentration in the medium reached up to 25 mg L−1 medium, and the bioaccumulation factors (BAFs) of the shoots for Cd rose from 3.8 to 7.4 as the Cd concentration in the medium was elevated from 5 to 25 mg L−1 medium. In growth chamber trial 2, the average Cd removal rates in two treatments with EDTA and ethyl lactate (molar ratios of EDTA to ethyl lactate = 68/39 and 53.5/53.5, respectively) reached 0.71 mg d−1pot−1 for the duration of Day 5-8 and 0.59 mg d−1pot−1 for that of Day 8-11, which were 5- and 4-fold of their counterparts in the control, respectively. In the field trial, for the remediational duration of 45 days, three treatments—willow alone, willow combined with EDTA, and willow combined with EDTA and ethyl lactate—led to decreases in the Cd concentration in soil by 5%, 20%, and 29%, respectively; increases in that in the leaves by 14.6%, 56.7%, and 146.5%, respectively; and increases in that in the stems by 15.6%, 41.2%, and 87.4%, respectively, compared to their counterparts on Day 0. These results indicate that EDTA combined with ethyl lactate significantly enhanced the efficiency of willow in removing Cd from the soil. Therefore, a phytoextration system consisting of the autochthonous willow, EDTA, and ethyl lactate has high potential for the remediation of the Cd-polluted soil in the lower reaches of the Yangtze River.
Keywords: Willow (salix × aureo-pendula); Phytoremediation; Cadmium; Ethylenediaminetetraacetic acid (EDTA); Ethyl lactate;

A supported liquid membrane method was developed using chlorinated cobalt dicarbollide (CCD) in phenyltrifluoromethyl sulphone (PTMS) as the carrier, impregnated in PTFE flat sheet membranes for the selective separation of Cs(I) from nitric acid feed solution. Solvent extraction studies were carried out for optimizing the feed as well as strip conditions. >95% Facilitated transport of Cs(I) was observed in about 3 h when 1 M HNO3 and 8 M HNO3 were used as the feed and strip solutions, respectively while 0.025 M CCD in PTMS was used as the carrier extractant. Selectivity studies, carried out using a mixture of radiotracers viz. 51Cr, 59Fe, 99Mo, 99mTc, 106Ru, 137Cs, 152Eu and 241Am, indicated selective transport of Cs(I) with DF values >100. Though reproducibility of the transport data was excellent when carried out in two successive transport experiments with freshly loaded carrier solvent, the stability of the membrane was poor which restricts its long term use.
Keywords: Cesium; Cobalt dicarbollide; Liquid membrane; Facilitated transport;

Sorption hysteresis of Cd(II) and Pb(II) on natural zeolite and bentonite by Mohsen Hamidpour; Mahmoud Kalbasi; Majid Afyuni; Hossein Shariatmadari; Peter E. Holm; Hans Christian Brunn Hansen (686-691).
Sorption hysteresis in natural sorbents has important environmental implications for pollutant transport and bioavailability. We examined sorption reversibility of Cd(II) and Pb(II) on zeolite and bentonite. Sorption isotherms were derived by sorption of Cd(II) and Pb(II) from solutions containing a range of the metal concentrations corresponding to 10-100% maximum sorption capacity (SCmax) of the sorbents. The desorption experiments were performed immediately following the completion of sorption experiments. Sorption and desorption isotherms of Cd(II) and Pb(II) were well described by the Freundlich model. The results revealed that the desorption isotherms of Cd(II) and Pb(II) from zeolite significantly deviated from the sorption isotherms indicating irreversible or very slowly reversible sorption. For bentonite sorption/desorption isotherms were similar indicating reversible sorption. The extent of hysteresis was evaluated from sorption and desorption Freundlich parameters (K f and n) through the apparent hysteresis index (HI=n desorb /n sorb ; n is the exponent in the Freundlich equation) and differences in Freundlich K f parameters. Higher sorption irreversibility was obtained for Pb(II) as compared to Cd(II). The amounts of Cd(II) and Pb(II) desorbed from bentonite were more than from zeolite, indicating that zeolite was a more effective sorbent for water and wastewater treatment.
Keywords: Hysteresis; Sorption; Desorption; Zeolite; Bentonite;

Removal of rotenone insecticide by adsorption onto chemically modified activated carbons by Anissa Dhaouadi; Lotfi Monser; Nafaâ Adhoum (692-699).
The removal of rotenone from synthetic and real wastewaters using modified activated carbons has been investigated. In order to enhance the removal capacity of rotenone, activated carbon was chemically modified through impregnation with NH3 and (NH4)2S2O8 solutions. The resulting carbons were found to present different surface chemistries, while possessing similar textural properties. The adsorption data obtained at 298 K, on plain and modified carbons were well represented by the Langmuir isotherm model (R2  > 0.997). The highest adsorption capacity (Qm  = 270.3 mg g−1) was obtained with the ammonia-treated activated carbon. The relative effect of different surface groups on adsorption capacities were found to be in accordance with the π − π dispersive interaction model. The adsorption kinetic models have provided useful insights into rotenone adsorption mechanism. It was concluded that rotenone sorption process followed pseudo-second order model and was controlled by intra-particle diffusion mechanism with a significant contribution of film diffusion. The successful adsorptive removal of rotenone, from real wastewater samples on fixed bed columns, have demonstrated the suitability of this method as an effective alternative solution for the treatment of contaminated wastewaters.
Keywords: Activated carbon; Adsorption isotherm; kinetic; Surface chemistry; Rotenone;

The separation of uranium ions by natural and modified diatomite from aqueous solution by Myroslav Sprynskyy; Iryna Kovalchuk; Bogusław Buszewski (700-707).
In this work the natural and the surfactant modified diatomite has been tested for ability to remove uranium ions from aqueous solutions. Such controlling factors of the adsorption process as initial uranium concentration, pH, contact time and ionic strength have been investigated. Effect of ionic strength of solution has been examined using the solutions of NaCl, Na2CO3 and K2SO4. The pseudo-first order and the pseudo-second order models have been used to analyze the adsorption kinetic results, whereas the Langmuir and the Freundlich isotherms have been used to the equilibrium adsorption data. The effects of the adsorbent modification as well as uranium adsorption on the diatomite surface have been studied using X-ray powder diffraction, scanning electron microscopy and FTIR spectroscopy. The maximum adsorption capacities of the natural and the modified diatomite towards uranium were 25.63 μmol/g and 667.40 μmol/g, respectively. The desorptive solutions of HCl, NaOH, Na2CO3, K2SO4, CaCO3, humic acid, cool and hot water have been tested to recover uranium from the adsorbent. The highest values of uranium desorption (86%) have been reached using 0.1 M HCl.
Keywords: diatomite; uranium; modified diatomite; kinetic adsorption; isotherm adsorption;

Photocatalytic degradation of 1-naphthol by oxide ceramics with added bacterial disinfection by Chockalingam Karunakaran; Sona Narayanan; Paramasivan Gomathisankar (708-715).
1-Naphthol photodegrades on the surfaces of TiO2, ZnO, CeO2, CdO, WO3, Co3O4, Sb2O3, ZrO2, La2O3, Y2O3, Pr6O11, Sm2O3 and Al2O3, albeit at different efficiencies, and all the oxides show sustainable photocatalytic activity. The degradation conforms to the Langmuir-Hinshelwood kinetic model and enhances with the intensity of illumination. Dissolved oxygen is essential for the degradation. ZnO and TiO2 anatase are the most efficient photocatalysts to degrade 1-naphthol. ZnO wurtzite, besides serving as an effective photocatalyt to degrade 1-naphthol, also acts as a bactericide; it inactivates E.coli even in absence of direct light. At a loading of 0.8 g L−1, it kills about 44% of 2.5 × 1012 CFU mL−1 E. coli in ½ h under dark condition.
Keywords: α-Naphthol; Semiconductor; Photodegradation; Bactericidal activity;

Sludge samples from eleven potable water treatment plants (PWTP), three waste water treatment plants (WWTP) and an industrial water treatment plant (IWTP), located in different areas of Spain, mainly in Catalonia, were analyzed for their radiological content in order to determine whether they could be considered as industries affected by naturally occurring radioactive material (NORM). In general, samples from the PWTPs showed higher activity values for the alpha and gamma emitting isotopes than the WWTPs and the IWTP. For example, samples from the area located in the north of Catalonia show values of 234U, 235U and 238U in the range of 84.4-792.1 Bq/kg, 3.3-26.8 Bq/kg and 63.8-585.9 Bq/kg, respectively. In general, for PWTP, the values obtained for the gamma emitter and alpha emitter isotopes showed that both the geology and the industrial activities correlate with the values measured. The magnitude of these results demonstrates the need to measure the radionuclide content of these samples before reaching a decision about their final disposal.
Keywords: NORM; sludge; water treatment plants;

A BaMnCe ternary catalyst was prepared by impregnating barium acetate on MnO x –CeO2 mixed oxides, with the monoxide supported catalysts and the solid solution support as references. The activities of the catalysts for soot oxidation were evaluated in the presence of NO under an energy transference controlled regime. BaMnCe presented the lowest maximal soot oxidation rate temperature at 393 °C among the catalysts investigated. Although BaMnCe experienced a loss in the specific surface area and low–temperature redox property due to blocking of the support pores by barium carbonate, its superior soot oxidation activity highlighted the importance of relatively stable bidentate/monodentate nitrates coordinated to Mn x+ and Ce x+ sites and more stable ionic barium nitrate. About half of the nitrates stored on this catalyst decomposed within the temperature interval of 350–450 °C, and the ignition temperature of soot decreased significantly with involvement of the nitrates or NO2 released.
Keywords: MnOx–CeO2 mixed oxides; Barium; Soot oxidation; Nitrate;

Laboratory and pilot plant scale study on the electrochemical oxidation of landfill leachate by Ángela Anglada; Ana M. Urtiaga; Inmaculada Ortiz (729-735).
Kinetic data regarding COD oxidation were measured in a laboratory scale cell and used to scale-up an electro-oxidation process for landfill leachate treatment by means of boron-doped diamond anodes. A pilot-scale reactor with a total BDD anode area of 1.05 m2 was designed. Different electrode gaps in the laboratory and pilot plant cells resulted in dissimilar reactor hydrodynamics. Consequently, generalised dimensionless correlations concerning mass transfer were developed in order to define the mass transfer conditions in both electrochemical systems. These correlations were then used in the design equations to validate the scale-up procedure. A series of experiments with biologically pre-treated landfill leachate were done to accomplish this goal. The evolution of ammonia and COD concentration could be well predicted.
Keywords: Electrochemical oxidation; landfill leachate; change of scale; pilot plant;

Pyridine and phenol removal using natural and synthetic apatites as low cost sorbents: Influence of porosity and surface interactions by H.Bouyarmane; S.El Asri; A. Rami; C. Roux; M.A. Mahly; A. Saoiabi; T. Coradin; A. Laghzizil (736-741).
A natural phosphate rock and two synthetic mesoporous hydroxyapatites were evaluated for the removal of pyridine and phenol from aqueous solutions. Experiments performed by the batch method showed that the sorption process occurs by a first order reaction for both pyridine and phenol. In contrast, the Freundlich model was able to describe sorption isotherms for phenol but not for pyridine. In parallel, the three apatites exhibit similar pyridine sorption capacities whereas phenol loading was in agreement with their respective specific surface area. This was attributed to the strong interaction arising between pyridine and apatite surface that hinders further inter-particular diffusion. This study suggests that, despite its low specific surface area, natural phosphate rock may be used as an efficient sorbent material for specific organic pollutants, with comparable efficiency and lower processing costs than some activated carbons.
Keywords: Pyridine; Phenol; Phosphate rock; Apatite; Remediation;

This work described a fast and sensitive voltammetric method developed for monitoring the photodegradation of ethylenediaminetetraacetic acid (EDTA). Due to the unique properties of carbon nanotubes (CNTs) such as negative charges, large surface area and excellent electron transfer ability, metal ion namely Fe3+ showed a pair of well-defined redox response peaks on the CNTs-modified electrode. When EDTA was present in the solution, the voltammetric response of Fe3+ was suppressed due to the chelating interaction between Fe3+ and EDTA. In acetate buffer solution, the concentration of EDTA was found to be inversely proportional to the decreased cathodic peak current in the range of 1.0 × 10−6 to 1.0 × 10−4  mol/L with a detection limit (3S/N) of 6.5 × 10−7  mol/L. While EDTA was degraded by UV irradiation, the voltammetric response on the CNTs-modified electrode was enhanced due to the reduced amount of EDTA species chelating with Fe3+. Accordingly, the concentration variation of EDTA during the photodegradation was analyzed. The effects of H2O2 and pH on the photodegradation of EDTA were investigated. Thus, the proposed CNTs-based voltammetry provided a useful analytical tool for studying the degradation of EDTA.
Keywords: EDTA; Carbon nanotubes; Modified electrode; Fe3+; Photodegradation;

Heavy metals in northern Chilean rivers: Spatial variation and temporal trends by Jaime Pizarro; Pablo M. Vergara; José A. Rodríguez; Alejandra M. Valenzuela (747-754).
Rivers of central-northern Chile are exposed to pollution from different sources, including mining activities, natural orogenic process, volcanic activity, and geology. In order to determine the contribution of mining to river pollution, the spatio-temporal dynamics of chemical species dissolved in 12 rivers of central-northern Chile was assessed. Of all the rivers studied, the Elqui showed the highest historical mean concentrations of As, Cu and Pb. The Aconcagua had the highest concentration of Hg and a large Cr concentration, while the Rapel showed elevated concentrations of Cu and Mo. The Elqui and the Aconcagua were clustered as distinct groups by a cluster analysis based on two independent principal components. Hierarchical Bayesian models showed annual trends but no seasonal effects in heavy metal concentrations. As and Cu in the Elqui had positive annual slopes. Sulphate concentration exceeded 100 mg L−1 in nine rivers, and in seven of them it had positive annual slopes. Our findings suggest that mining pollution is the main process contributing to this increasing annual trend in As, Cu and SO4 2−. Therefore, in order to improve the water quality of these rivers it is necessary to identify the main sources of heavy metals associated with mining activities.
Keywords: Heavy metals; Chilean rivers; Annual trends; Mining;

Adsorption of methyl orange from aqueous solution onto calcined Lapindo volcanic mud by Aishah A. Jalil; Sugeng Triwahyono; S. Hazirah Adam; N. Diana Rahim; M. Arif A. Aziz; N. Hanis H. Hairom; N. Aini M. Razali; Mahani A.Z. Abidin; M. Khairul A. Mohamadiah (755-762).
In this study, calcined Lapindo volcanic mud (LVM) was used as an adsorbent to remove an anionic dye, methyl orange (MO), from an aqueous solution by the batch adsorption technique. Various conditions were evaluated, including initial dye concentration, adsorbent dosage, contact time, solution pH, and temperature. The adsorption kinetics and equilibrium isotherms of the LVM were studied using pseudo-first-order and -second-order kinetic equations, as well as the Freundlich and Langmuir models. The experimental data obtained with LVM fits best to the Langmuir isotherm model and exhibited a maximum adsorption capacity (q max) of 333.3 mg g−1; the data followed the second-order equation. The intraparticle diffusion studies revealed that the adsorption rates were not controlled only by the diffusion step. The thermodynamic parameters, such as the changes in enthalpy, entropy, and Gibbs free energy, showed that the adsorption is endothermic, random and spontaneous at high temperature. The results indicate that LVM adsorbs MO efficiently and could be utilized as a low-cost alternative adsorbent for the removal of anionic dyes in wastewater treatment.
Keywords: Adsorption; Methyl orange; Lapindo volcanic mud;

The purpose of this present study is to investigate the removal efficiency of chemical oxygen demand (COD) from pulp and paper wastewater using laccase-polymerized membrane filtration process. The membranes with molecular weight cut-off (MWCO) of 5000 and 10,000, 30,000 and 54,000 were used in a cross-flow module to treat the pulp and paper wastewater containing high phenolic constituents and COD. With 2.98 IU/L of activated laccase applied at room temperature for 180 min, the contaminants in raw wastewater and second effluent were polymerized to form larger molecules with average molecular weight of 1300 and 900 Da (Dalton), respectively. With laccase polymerization prior to filtration, over 60% removals of COD by the four investigated membranes were observed, compared with low COD removal without laccase polymerization. Moreover, the addition of laccase resulted in 4–14% reduction of membrane permeability during the first 180 min filtration operation due to gel layer formation by the polymerization. No further flux decline was observed afterwards indicating the steady state was reached and the membranes could be used to remove the polymerized pollutants without significant fouling. The maximum apparent resistance occurrence for raw wastewater treated with laccase also supported the effectiveness for COD removal with laccase polymerization before membrane filtration. Additionally, pretreatment by inactivated laccase only caused further flux reduction without additional removal of COD.
Keywords: Chemical oxygen demand; Enzymatic degradation; Permeate flux; Pulp and paper; Polymerization;

Remediation of plant–microorganism–chelates synergy has been proposed as an effective remediation method for enhancing the removal efficiency of heavy metal. Manipulation of the antioxidative system increases plant tolerance, thereby potentially enhancing the uptake capacity to heavy metal. In this study, we investigated the possibility of improving the phytoextraction of Cd and the antioxidative defense of Solanum nigrum L. by application of a new isolated strain (Paecilomyces lilacinus NH1) (PLNH1) and citric acid (CA). The results showed that application of CA or PLNH1 significantly promoted S. nigrum's growth under Cd stress, but the synergistic effect of CA and PLNH1 on S. nigrum's growth was more obvious. The coexistence of CA and PLNH1 could enhance about 30% of Cd accumulation in different organs of S. nigrum compared to the treatment without the addition of CA and PLNH1, whereas single CA or PLNH1 added treatment only enhanced about 10–15% of Cd accumulation in different organs of S. nigrum. The antioxidative defense in S. nigrum under Cd stress was significantly improved as result of application of CA and PLNH1. The responses of antioxidative enzymes to Cd stress significantly decreased following application of CA and PLNH1, and the oxidative stress experienced by the plant due to Cd in the soil was significantly alleviated.
Keywords: Antioxidative enzyme; Hyperaccumulator; Phytoextraction; Solanum nigrum L.; Soil remediation;

In order to identify spatial relationship of heavy metals in soil–rice system at a regional scale, 96 pairs of rice and soil samples were collected from Wenling in Zhejiang province, China, which is one of the well-known electronic and electric waste recycling centers. The results indicated some studied areas had potential contaminations by heavy metals, especially by Cd. The spatial distribution of Cd, Cu, Pb and Zn illustrated that the highest concentrations were located in the northwest areas and the accumulation of these metals may be due to the industrialization, agricultural chemicals and other human activities. In contrast, the concentration of Ni decreased from east to west and the mean concentration was below the background value, indicating the distribution of Ni may be naturally controlled. Enrichment index (EI) was used to describe the availability of soil heavy metals to rice. The spatial distribution of EIs for Cd, Ni and Zn exhibited a west-east structure, which was similar with the spatial structures of pH, OM, sand and clay. Cross-correlograms further quantitatively illustrated the EIs were significantly correlated with most soil properties, among which; soil pH and OM had the strongest correlations with EIs. However, EI of Cu showed relative weak correlations with soil properties, especially soil pH and OM had no correlations with EI of Cu, indicating the availability of Cu may be influenced by other factors.
Keywords: Contamination; Geostatistics; Heavy metals; Soil–rice system; Spatial relationship;

The present study was conducted to compare the performance of a dual-media filter consisting of manganese oxide-coated (MOCS) and iron hydroxide-coated sand (IOCS) with that of IOCS filter and uncoated sand filter in treating water contaminated by microorganisms, heavy metals and turbidity with a view to its use in simple household water purification devices in developing countries. Long-duration column tests were conducted using two natural waters namely, roof-harvested rainwater and canal water. Performance of the filters showed that dual-media filter was more efficient in removing bacteria and heavy metals compared to IOCS filter, while uncoated sand filter showed very poor performance. The average effluent levels for dual-media filter when tested with rainwater were: turbidity 1.0 ± 0.1 NTU; total coliforms 3 ± 2 MPN/100 mL; heterotrophic plate count 170 ± 20 CFU/mL; zinc 0.06 ± 0.01 mg/L, while that for IOCS filter were: turbidity 1.0 ± 0.1 NTU; total coliforms 4 ± 2 MPN/100 mL; heterotrophic plate count 181 ± 37 CFU/mL; zinc 0.20 ± 0.07 mg/L. Similar results were obtained for canal water also. Up to 900 bed volumes (BV) could be treated without affecting the efficiency in the case of rainwater, while the filter operation had to be terminated after 500 BV due to excessive headloss in the case of canal water. The study thus showed the potential of the dual-media for use in low-cost household water filters for purification of natural waters.
Keywords: Bacterial removal; Heavy metal; Household water treatment; Iron hydroxide-coated sand; Manganese oxide-coated sand;

Recovery of Pd(II) from hydrochloric solution using polyallylamine hydrochloride-modified Escherichia coli biomass by Jiyeong Park; Sung Wook Won; Juan Mao; In Seob Kwak; Yeoung-Sang Yun (794-800).
A new type of biosorbent able to bind anionic metals was developed by cross-linking of waste biomass Escherichia coli with polyallylamine hydrochloride (PAH). The PAH-modified biomass was investigated for the removal and recovery of Pd(II), in the chloro-complex form, from aqueous solution. The performance of the PAH-modified biomass was evaluated in terms of the following parameters: the solution pH, contact time and initial metal concentration. In the pH edge experiments, the uptake of Pd(II) increased with increasing pH. Pd(II) biosorption proceeded rapidly in the first 10 min, with almost complete equilibrium being achieved within 60 min. Moreover, the isotherm data showed that the maximum uptakes of Pd(II) were 265.3 mg/g at pH 3 and 212.9 mg/g at pH 2, respectively. After incineration of the Pd-loaded PAH-modified biomass, metallic palladium was recovered in the ash. X-ray photoelectron spectroscopy (XPS) results confirmed that the palladium was recovered in two valency states: zero-valent and divalent palladium (as PdO). Therefore, we concluded that PAH-modified biomass is a useful and cost-effective biosorbent for the recovery of anionic precious metals as chloro-complex solutions containing hydrochloric acid produced from metal refining processes.
Keywords: Recovery; Palladium; Polyallylamine hydrochloride; Escherichia coli; Incineration;

Hexavalent chromium removal from aqueous solution by algal bloom residue derived activated carbon: Equilibrium and kinetic studies by Hong Zhang; Yi Tang; Dongqing Cai; Xianan Liu; Xiangqin Wang; Qing Huang; Zengliang Yu (801-808).
A novel approach to prepare activated carbon from blue-green algal bloom residue has been tried for first time and its adsorption capability to remove hexavalent chromium Cr(VI) from aqueous solution has been examined. For this algal bloom residue derived activated carbon, the physical characters regarding adsorption capability were analyzed by scanning electron microscope (SEM), energy dispersive X-ray spectroscope (EDS) and Fourier transform infrared (FTIR) spectroscopy. Batch studies showed that initial pH, absorbent dosage, and initial concentration of Cr(VI) were important parameters for Cr(VI) absorption. It was found that initial pH of 1.0 was most favorable for Cr(VI) removal. The adsorption process followed the pseudo-second-order equation and Freundlich isotherm. The maximum adsorption capacity for Cr(VI) was 155.52 mg g−1 in an acidic medium, which is comparable to best result from activated carbons derived from biomass. Therefore, this work put forward a nearly perfect solution which on one hand gets rid of environment-unfriendly algae residue while on the other hand produces high-quality activated carbon that is in return advantageous to environment protection.
Keywords: Chromium(VI) removal; Adsorption; Kinetics; Activated carbon; Algal bloom residue;

EC treatment for reuse of tissue paper wastewater: Aspects that affect energy consumption by Eduardo Terrazas; Armando Vázquez; Roberto Briones; Isabel Lázaro; Israel Rodríguez (809-816).
The need for more rational use of water also calls for more efficient usage. An example is the production of tissue paper, where large amounts of water are discharged into the drain because its turbidity does not allow for recirculation. While this is a serious problem, even worse is the fact that the quality of such wastewater makes it difficult not only to recirculate but also to discharge due to environmental law restrictions. In this paper, electrocoagulation is proposed as a suitable technology to meet standards of water discharge, and even better, as a treatment option for removal of turbidity. Since energy consumption has been a drawback for EC applications, relevant aspects that contribute to increase it such as cell voltage and current density have been reviewed. For this purpose a systematic micro-electrolysis study combined with macro-electrolysis experiments have provided evidence that shows it is possible to achieve a turbidity removal of 92% with an energy consumption of 0.68 kWh/m3. Thus, the results presented in this paper support the use of EC to obtain water of acceptable quality for reuse in the tissue paper industry.
Keywords: Electrocoagulation; Aluminum; Paper; Turbidity; Energy consumption;

A one-year field trial was conducted at the abandoned mine site of Tharsis (Spain) in order to assess the potential value of waste sludge generated during the processing of marble stone, as an additive for assisting natural remediation of heavily contaminated acid mine soils. An amendment of 22 cmolc of lime per kilogram of soil was applied to raise the pH level from 3.2 to above 6. The amendment application was effective in reducing concentrations of Al, Fe, Mn, sulfate and potentially hazardous trace elements (mainly Cu, Pb, Zn and Cd) in the most labile metal pools (water-soluble and EDTA-extractable fractions). Geochemical equilibrium calculations indicate that sulfate complexes and free metal ions were the dominant aqueous species in the soil solution. Metal coprecipitation with nanocrystalline ferric oxyhydroxides may be the major chemical mechanism of amendment-induced immobilization. The alleviating effect of the soil amendment on the metal bioavailability and phytotoxicity showed promise for assisting natural revegetation of the mine land.
Keywords: Soil amendment; Marble slurry; Assisted natural remediation; Metal immobilization; Tharsis mines;

Mass balance for POPs in a real scale fluidized bed combustor co-incinerating automotive shredder residue by J. Van Caneghem; C. Block; I. Vermeulen; A. Van Brecht; P. Van Royen; M. Jaspers; G. Wauters; C. Vandecasteele (827-835).
The European directive 2000/53/EC implies a “reuse and recovery” rate for end-of-life vehicles (ELVs) of 95% to be reached by the year 2015. One of the options to increase the actual average European “reuse and recovery” rate of approximately 78% (EU 15, 2008) is incineration of automotive shredder residue (ASR) with energy-recovery. The mass balance and the congener fingerprints for PCDD/Fs, dioxin-like PCBs, PCBs and PAHs in a real scale fluidized bed combustor (FBC) incinerating 25% ASR with 25% refuse derived fuel (RDF) and 50% waste water treatment sludge (WWT sludge) were investigated. The PCDD/F, dioxin-like PCB, PCB and PAH concentrations in this input waste mix were more than hundred times higher than in the usual waste feed of the incinerator (30% RFD and 70% WWT sludge). In the outputs of the FBC, however, the concentrations of these POP groups were comparable or only slightly higher than in the outputs generated during the incineration of the usual waste feed. The considered POPs in the waste were destroyed efficiently and the formation of new POPs during cooling of the flue gas appeared to a large extent independent of the POP concentrations in the incinerated waste.
Keywords: Waste incineration; Fluidized bed combustor; PCDD/F; PCB; ASR; POP;

2,4-Dinitrophenylhydrazine (DNPH) immobilized on sodium dodecyl sulfate coated nano-alumina was developed for the removal of metal cations Pb(II), Cd(II), Cr(III), Co(II), Ni(II) and Mn(II) from water samples. The research results displayed that adsorbent has the highest adsorption capacity for Pb(II), Cr(III) and Cd(II) in ions mixture system. Optimal experimental conditions including pH, adsorbent dosage and contact time have been established. Langmuir and Freundlich isotherm models were applied to analyze the experimental data. The best interpretation for the experimental data was given by the Freundlich adsorption isotherm equation for Mn(II), Pb(II), Cr(III) and Cd(II) ions and by Langmuir isotherm equation for Ni(II) and Co(II) ions. Desorption experiments by elution of the adsorbent with a mixture of nitric acid and methanol show that the modified alumina nanoparticles could be reused without significant losses of its initial properties even after three adsorption–desorption cycles. Thus, modified nano-alumina with DNPH is favorable and useful for the removal of these metal ions, and the high adsorption capacity makes it a good promising candidate material for Pb(II),Cr(III) and Cd(II) removal.
Keywords: Heavy-metal ions removal; Isotherms; Alumina nanoparticles; Modified nanoparticles; Wastewater;

Effects of three amendments on extractability and fractionation of Pb, Cu, Ni and Sb in two shooting range soils by H.M. Conesa; M. Wieser; M. Gasser; K. Hockmann; M.W.H. Evangelou; B. Studer; R. Schulin (845-850).
Contamination of shooting range soils with toxic trace elements, in particular Pb and Sb, is of increasing environmental concern worldwide. We studied the extractability of Sb, and other metals in two shooting range soils: a calcareous soil (pH 8) with low organic carbon (0.5%) and a non-calcareous soil (pH 6.3) with elevated organic carbon content (5%). Both soils contained total concentrations of around 500 mg kg−1 Pb, 65 mg kg−1 Cu, 100 mg kg−1 Zn and 20 mg kg−1 Sb. We tested the effects of Ca(OH)2, phosphate and sodium humate amendments on metals and Sb extractability. Extracts with H2O and NaNO3 contained 0.02–0.05% of the total Zn and Pb; 0.1–0.5% of total Ni and Cu and ∼1% of total Sb. Sequential extraction procedure of Zeien and Brümmer resulted in similar percentages for the sum of the two most labile fractions (F1 + F2) in two soils: 10% Pb, and 15–20% Sb. Water and NaNO3-extractable Sb concentrations increased after phosphate addition, but were not affected by the addition of sodium humate. The results show that leaching of Sb from shooting ranges into ground and surface waters may generate a serious environmental risk under widely different soils conditions.
Keywords: Shooting ranges; Metals; Antimony; Sequential extraction;

Speciation of butyltin derivatives in surface sediments of three southern Brazilian harbors by Cristiane Rossi de Oliveira; DayanaMoscardi dos Santos; Luiz Augusto dos Santos Madureira; Mary Rosa Rodrigues de Marchi (851-856).
For the first time, organotin compounds were determined in surface sediment samples collected from São Francisco do Sul, Itajaí-Navegantes and Imbituba Harbors, located in Santa Catarina State, Brazil. Butyltins (BTs) were determined by gas chromatography with a pulsed flame photometric detector (GC-PFPD) after being modified using the Grignard derivatization method. The concentrations of BTs derivatives ranged from n.d. to 1136.6 ng (Sn) g−1 of dry weight (dw) sediment for tributyltin (TBT), n.d. to 394.4 ng (Sn) g−1 dw for dibutyltin (DBT) and n.d. to 312.2 ng (Sn) g−1 dw for monobutyltin (MBT). The highest concentration of total BTs was found at the Itajaí-Açu River dockyard, indicating intense inputs of antifouling paints to the environment. The relative difference in the BTs levels is a particular characteristic of sediments from harbors and may be related to the shipyards and the boat traffic which still use TBT-based antifouling paints.
Keywords: Butyltins; Sediments; Harbors; Santa Catarina;

New polymeric membrane (PME), modified carbon paste (MCPE), and coated wire (CWE) selenite ion-selective electrodes based on 5,10,15,20-tetrakis-(4-methoxyphenyl)-21H,23H-porphyrin-Co(II) (CoTMeOPP) are reported. The best composition was the electrode containing 2% CoTMeOPP as the active material and 49% TCP as plasticizer. The electrodes reveal a Nernstian behavior over a concentration range of 5.5 × 10−5 to 1.1 × 10−2  M for PME, 5.2 × 10−5 to 1.2 × 10−2  M for MCPE and 1.2 × 10−4 to 4.4 × 10−3  M for CWE. The potentiometric response is pH dependent, since selenous acid is a diprotic acid. The slope of the selenite PVC electrode was −57.0 mV for the monovalent anion at pH 6.47, and −26.0 mV for the divalent anion at pH 11.00. The detection limits were 3.4 × 10−5 and 4.7 × 10−5  M at pH values 6.47 and 11.00, respectively. The electrodes manifest advantages of low resistance, very short response time (15 s), and most importantly good selectivities relative to a wide variety of other anions. In fact, the proposed selenite ion-selective electrodes show a great improvement compared to previously reported electrodes for selenite ion. The electrode was used for the determination of selenite in selenite/selenate mixture, in sodium selenite raw material powder, and in VitaFit Selenium ACE antioxidant tablets with recovery ranges of 90.0–103.3%.
Keywords: Selenite; Graphite; Membrane; Coated wires; Porphyrin;

Extraction of Cu(II) from aqueous solutions by vegetable oil-based organic solvents by Siu Hua Chang; Tjoon Tow Teng; Norli Ismail (868-872).
Various types of vegetable oil-based organic solvents (VOS), i.e. vegetable oils (corn, canola, sunflower and soybean oils) with and without extractants (di-2-ethylhexylphosphoric acid (D2EHPA) and tributylphosphate (TBP)), were investigated into their potentiality as greener substitutes for the conventional petroleum-based organic solvents to extract Cu(II) from aqueous solutions. The pH-extraction isotherms of Cu(II) using various vegetable oils loaded with both D2EHPA and TBP were investigated and the percentage extraction (%E) of Cu(II) achieved by different types of VOS was determined. Vegetable oils without extractants and those loaded with TBP alone showed a poor extractability for Cu(II). Vegetable oils loaded with both D2EHPA and TBP were found to be the most effective VOS for Cu(II) extraction and, thus, are potential greener substitutes for the conventional petroleum-based organic solvents.
Keywords: Extraction; Cu(II); Vegetable oil-based organic solvents (VOS); Di(2-ethylhexyl)phosphoric acid (D2EHPA); Tributylphosphate (TBP);

Ignition and explosion risks of nanopowders by J. Bouillard; A. Vignes; O. Dufaud; L. Perrin; D. Thomas (873-880).
Characterization methods with regard to nanopowder flammability and explosivity are presented and illustrated for few nanopowders. Analytical models are developed in order to explain the dependency of the combustion times on the particle diameter. Experimental evidence shows that there exists, for carbonaceous and metallic materials, mainly two combustion regimes that are either kinetically controlled, for small size particles, or diffusion controlled, for large size particles. From the experimentally measured combustion data of those materials, the dependencies of the ignition temperature and the minimal explosive concentration (MEC) with regard to the particle size have been analyzed. We found that the two combustion regimes yield two different tendencies with respect to the particle size. Overall, it is found that as the particle size decreases, minimum ignition temperature (MIT) and minimum ignition energy (MIE) decrease, indicating higher potential inflammation and explosion risks for the use of nanopowders. By contrast, the minimal explosion concentration (MEC) did not show strong variations as the particle size decreases. Rather, a theoretical plateau is observed, which was experimentally confirmed. We also observed that carbon nanopowders exhibit a low propensity to explode while metallic nanopowders can be very reactive, thus delineating high potentials for explosion risks in manufacturing facilities.
Keywords: Nanopowders; Ignition; Explosion; Carbon nanotube; Aluminium; Carbon blacks;

Sorption of strontium on uranyl peroxide: Implications for a high-level nuclear waste repository by Rosa Sureda; Xavier Martínez-Lladó; Miquel Rovira; Joan de Pablo; Ignasi Casas; Javier Giménez (881-885).
Strontium-90 is considered the most important radioactive isotope in the environment and one of the most frequently occurring radionuclides in groundwaters at nuclear facilities. The uranyl peroxide studtite (UO2O2·4H2O) has been observed to be formed in spent nuclear fuel leaching experiments and seems to have a relatively high sorption capacity for some radionuclides. In this work, the sorption of strontium onto studtite is studied as a function of time, strontium concentration in solution and pH. The main results obtained are (a) sorption is relatively fast although slower than for cesium; (b) strontium seems to be sorbed via a monolayer coverage of the studtite surface, (c) sorption has a strong dependence on ionic strength, is negligible at acidic pH, and increases at neutral to alkaline pH (almost 100% of the strontium in solution is sorbed above pH 10). These results point to uranium secondary solid phase formation on the spent nuclear fuel as an important mechanism for strontium retention in a high-level nuclear waste repository (HLNW).
Keywords: Strontium; Spent nuclear fuel; High-level nuclear waste repository; Sorption; Langmuir isotherm;

Optimization of photocatalytic degradation of C.I. Basic Blue 3 (BB3) under UV light irradiation using TiO2 nanoparticles in a rectangular photoreactor was studied. The investigated TiO2 was Millennium PC-500 (crystallites mean size 5–10 nm) immobilized on non-woven paper. Central composite design was used for optimization of UV/TiO2 process. Predicted values of decolorization efficiency were found to be in good agreement with experimental values (R 2  = 0.9686 and Adj-R 2  = 0.9411). Optimization results showed that maximum decolorization efficiency was achieved at the optimum conditions: initial dye concentration 10 mg/L, UV light intensity 47.2 W/m2, flow rate 100 mL/min and reaction time 120 min. Photocatalytic mineralization of BB3 was monitored by total organic carbon (TOC) decrease, and changes in UV–vis and FT-IR spectra. The photodegradation compounds were analyzed by UV–vis, FT-IR and GC–mass techniques. The degradation pathway of BB3 was proposed based on the identified compounds.
Keywords: TiO2 nanoparticles; Photodegradation; Response surface methodology; TOC;

Selective removal for Pb2+ in aqueous environment by using novel macroreticular PVA beads by Yun Zhang; Yanfeng Li; Xiaoli Li; Liuqing Yang; Xue Bai; Zhengfang Ye; Lincheng Zhou; Liyuan Wang (898-907).
Batch sorption experiments were conducted using macroreticular poly(vinyl alcohol) (MR-PVA) beads as a adsorbent to adsorb Pb(II) from both single component system and multi-metal solution in which experimental parameters were studied including solution pH, contact time, adsorbent dose, initial concentration of metal ions and ionic strength. The equilibrium isotherms were determined at pH 6 under constant ionic strength and at different temperatures. The results showed that the maximum adsorption capacity of Pb(II) (213.98 mg g−1) with 1 g L−1 of adsorbent was observed at 300 mg L−1 at an initial pH value of 6.0 under temperature of 288 K. Removals of about 60% occurred in 30 min, and equilibrium was attained at around 150 min. The equilibrium data for the adsorption of Pb(II) on MR-PVA beads was tested with various adsorption isotherm models among which three models were found to be suitable for the Pb(II) adsorption. In addition, the kinetic adsorption fitted well to the pseudo-second-order model and the corresponding rate constants were obtained. Thermodynamic aspects of the adsorption process were also investigated.
Keywords: Pb(II); Selective adsorption; MR-PVA beads; Batch study;

This paper reports the optimization of the process parameters for recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor. The experiments were carried out in an ammoniacal ammonium chloride system. The influence of composition of electrolytes, pH, stirring rate, current density and temperature, on cathodic current efficiency, specific power consumption and anodic dissolution of Zn were investigated. The results indicate that the cathode current efficiency increases and the hydrogen evolution decreased with increasing the cathode current density. The partial current for electrodeposition of Zn has liner relationship with ω 1/2 (ω: rotation rate). The highest current efficiency for dissolving zinc was obtained when NH4Cl concentration was 53.46 g L−1 and the anodic dissolution of zinc was determined by mass transfer rate at stirring rate 0–300 r min−1. Increase in temperature benefits to improve CE and dissolution of Zn, and reduce cell voltage. Initial pH of electrolytes plays an important role in the deposition and anodic dissolution of Zn. The results of single factor experiment show that about 50% energy consumption was saved for electrodeposition of Zn in the anion-exchange membrane electrolysis reactor.
Keywords: Galvanizing slag; Zinc recovery; Ion-exchange membrane electrolysis;

Removal of pyridine and quinoline by bio-zeolite composed of mixed degrading bacteria and modified zeolite by Yaohui Bai; Qinghua Sun; Rui Xing; Donghui Wen; Xiaoyan Tang (916-922).
In the process of the biodegradation of pyridine and quinoline, ammonium is often generated because of the transformation of N from pyridine and quinoline. Zeolite has been proven to be an effective sorbent for the removal of the ammonium. The natural zeolite can be modified to be the macroporous carrier in the biological wastewater treatment process. In this study, a specific bio-zeolite composed of mixed bacteria (a pyridine-degrading bacterium and a quinoline-degrading bacterium) and modified zeolite was used for biodegradation and adsorption in two types of wastewater: sterile synthetic and coking wastewater. The experimental results indicated that pyridine and quinoline could be degraded simultaneously by the mixed bacteria. Furthermore, NH4 +-N transformed from pyridine and quinoline could be removed by the modified zeolite. In addition, the bacterial community structures of the coking wastewater and the bio-zeolite were monitored by the amplicon length heterogeneity polymerase-chain reaction (LH-PCR) technique. Both LH-PCR results and scanning electron microscope (SEM) observations indicated that the microorganisms, including BW001 and BW003, could be easily attached on the surface of the modified zeolite and that the bio-zeolite could be used in the treatment of wastewater containing pyridine and/or quinoline.
Keywords: Modified zeolite; Adsorption; Pyridine; Quinoline; Biodegradation;

Three laboratory column experiments were performed to test the suitability of two different MgO-rich reagents for removal of Mn and Al from the out-flowing waters of Shilbottle passive treatment system (Northumberland, UK). The input water was doped with 100 mg/L Zn in order to extrapolate results to waters in sulphide mining districts. One column was filled with a Dispersed Alkaline Substrate (DAS) containing 12.5% (v/v) caustic magnesia precipitator dust (CMPD) from Spain mixed with wood shavings, two columns were filled with DAS containing wood shavings and 12.5% or 25% (v/v), respectively, of dolomitic lime precipitator dust (DLPD) from Thrislington, UK.The two columns containing 12.5% of CMPD or DLPD completely removed the contaminants from the inflow water during the first 6 weeks of the experiment (mean removal of 88 mg/L Al, 96 mg/L Zn and 37 mg/L Mn), operating at an acidity load of 140 g acidity/m2  day. At this moment, a substantial increase of the Al and Mn water concentration in the out-flowing waters of Shilbottle occurred (430 g acidity/m2  day), leading to passivation of the reactive material and to the development of preferential flow paths within less than another 6 weeks, probably mainly due to Al precipitates. Al should be removed prior to MgO treatment.
Keywords: MgO-rich reagent; Divalent metals removal; Passive remediation; Dispersed Alkaline Substrate;

Sequential extraction and availability of copper in Cu fungicide-amended vineyard soils from Southern Brazil by Roberta Corrêa Nogueirol; Luís Reynaldo Ferracciú Alleoni; Gilmar Ribeiro Nachtigall; George Wellington de Melo (931-937).
The continuous use of cupric fungicides in vineyards, mainly copper sulfate (as a component of the bordeaux mixture), has increased Cu concentration in soils to levels near or even above the maximum established by the Commission of Soil Chemistry and Fertility of the States of Santa Catarina and Rio Grande do Sul, Brazil. Besides the total content, the fractions of the element along the soil profile must be known, because the total content of Cu in the soil is not sufficient to express its environmental impact. The objective of this study was to evaluate the variation of Cu contentes along the soil profile and its speciation and partitioning in 29 soil samples from vineyards in the state of Rio Grande do Sul, Brazil. Samples were collected in areas cropped with vineyards older than 15 years that had been frequently treated with the bordeaux mixture. These samples were from Nitosols, Acrisols, Cambisols and Leptosols and were analysed by sequential extractions and several chemical extractors. Soils had diverse chemical and physical attributes: clay content in the plowed layer (0–0.2 m) ranged from 120 to 610 g kg−1, pH ranged from 5.3 to 7.3 and organic carbon contents varied from 2.9 to 51 g dm−3. Among the 29 samples, 16 had the total Cu above the maximum limit allowed by the European Community regulations (140 mg kg−1). The average amount of Cu bonded to the oxide fraction accounted for 49.5% of the total Cu.
Keywords: Brazilian soils; Extractants; Fractionation; Heavy metals;

The paper presents the results of a laboratory study aimed at verifying the use of two types of electric arc furnace (EAF) steel slags as substitutes for natural aggregates, in the composition of base course and road base asphalt concrete (BBAC) for flexible pavements. The trial was composed of a preliminary study of the chemical, physical, mechanical and leaching properties of the EAF steel slags, followed by the mix design and performance characterization of the bituminous mixes, through gyratory compaction tests, permanent deformation tests, stiffness modulus tests at various temperatures, fatigue tests and indirect tensile strength tests. All the mixtures with EAF slags presented better mechanical characteristics than those of the corresponding asphalts with natural aggregate and satisfied the requisites for acceptance in the Italian road sector technical standards, thus resulting as suitable for use in road construction.
Keywords: Steel slag; Leaching; Asphalt concrete; Stiffness modulus; Performance test;

Numerical simulations of large-scale detonation tests in the RUT facility by the LES model by Mateusz Zbikowski; Dmitriy Makarov; Vladimir Molkov (949-956).
The LES model based on the progress variable equation and the gradient method to simulate propagation of the reaction front within the detonation wave, which was recently verified by the ZND theory, is tested in this study against two large-scale experiments in the RUT facility. The facility was 27.6 m × 6.3 m × 6.55 m compartment with complex three-dimensional geometry. Experiments with 20% and 25.5% hydrogen–air mixture and different location of direct detonation initiation were simulated. Sensitivity of 3D simulations to control volume size and type were tested and found to be stringent compared to the planar detonation case. The maximum simulated pressure peak was found to be lower than the theoretical von Neumann spike value for the planar detonation and larger than the Chapman–Jouguet pressure thus indicating that it is more challenging to keep numerical reaction zone behind a leading front of numerical shock for curved fronts with large control volumes. The simulations demonstrated agreement with the experimental data.
Keywords: Detonation velocity and pressure; Hydrogen; Large-scale RUT facility; Large eddy simulation; Progress variable; Gradient method; von Neumann spike;

In this work, the applicability of modified organo nanoclay as a new and easy prepared solid sorbent for the preconcentration of trace amounts of Au(III) ion from water samples is studied. The organo nanoclay was modified with 5-(4′-dimethylamino benzyliden)-rhodanine and used as a sorbent for separation of Au(III) ions. The sorption of gold ions was quantitative in the pH range of 2.0–6.0. Quantitative desorption occurred with 6.0 mL of 1.0 mol L−1 Na2S2O3. The amount of eluted Au(III) was measured using flame atomic absorption spectrometry. In the initial solution the linear dynamic range was in the range of 0.45 ng mL−1 to 10.0 μg mL−1, the detection limit was 0.1 ng mL−1 and the preconcentration factor was 105. Also, the relative standard deviation was ±2.3% (n  = 8 and C  = 2.0 μg mL−1) and the maximum capacity of the sorbent was 3.9 mg of Au(III) per gram of modified organo nanoclay. The influences of the experimental parameters including sample pH, eluent volume and eluent type, sample volume, and interference of some ions on the recoveries of the gold ion were investigated. The proposed method was applied for preconcentration and determination of gold in different samples.
Keywords: Nanoclay; Sorbent; Preconcentration; Gold determination; 5-(4′-Dimethylamino benzyliden)-rhodanine;

The landfill reinjection of concentrated leachate: Findings from a monitoring study at an Italian site by Paolo S. Calabrò; Silvia Sbaffoni; Sirio Orsi; Emiliano Gentili; Carlo Meoni (962-968).
The membrane-based processes are among the most used techniques for leachate treatment in modern landfills but its environmental, technical and economical sustainability strongly depends on the disposal of concentrated leachate that is produced there. This paper presents the monitoring study of the landfill of the municipality of Monsummano Terme (Pistoia province, Tuscany, Italy) named “Il Fossetto” where concentrated leachate obtained during membrane treatment is recirculated. The findings resulting from the first 30 months of monitoring of concentrated leachate recirculation show that leachate production did not increase significantly and that only a few quality parameters (i.e. COD, Nickel and Zinc) presented a moderate increase. Moreover, the latest data on biogas composition seem to indicate a reduction in methane content that, if confirmed, could be related to the partial inhibition of methanogens due to the competition of sulphate reducing bacteria. The non-accumulation of other conservative pollutants such as Ammonia Nitrogen and Chloride in the leachate is still under investigation and needs to be better clarified. The overall sustainability of the reinjection as a means of disposing of the concentrated leachate produced by membrane treatment should be further analysed and evaluated in the long term.
Keywords: Biogas; Bioreactor landfill; Leachate recirculation; Membrane treatment;

The thermodynamic properties of 75 polyfluorinated dibenzo-p-dioxins (PFDDs) in the ideal gas state at 298.15 K and 1.013 × 105  Pa have been calculated at the B3LYP/6-311G* level using Gaussian 03 program. The isodesmic reactions were designed to calculate standard enthalpy of formation (ΔH f°) and standard free energy of formation (ΔG f°) of PFDDs congeners. The relations of these thermodynamic parameters with the number and position of fluorine atom substitution (N PFS) were discussed, and it was found that there exist high correlations between thermodynamic parameters (entropy (S°), ΔH f° and ΔG f°) and N PFS. According to the relative magnitude of their ΔG f°, the relative stability order of PFDD congeners was theoretically proposed.
Keywords: Polyfluorinated dibenzo-p-dioxins; Number and position of fluorine atom substitution (N PFS); Thermodynamic property; Relative stability;

Nanofiltration (NF) was investigated for the removal of glyphosate in the neutralization liquor produced by the glycine-dimethylphosphit process. The Desal-5 DK membrane was chosen as the most suitable membrane for the NF process when compared to the DL and NTR7450 membranes according to retention of glyphosate and the permeate flux. The effects of applied pressure, temperature, and feed pH on the performances of the DK membrane were investigated. An applied pressure of 2 MPa was found to be optimum since a high glyphosate rejection of 95.5% was obtained with a high flux of 7.32 L/(h m2); temperature had a slight impact on the retention of glyphosate with an increase in flux; both the minimum glyphosate retention and maximum permeate flux were achieved when the feed pH was around the isoelectric point of the DK membrane. In batch NF, the permeate flux decreased gradually but glyphosate rejection remained higher than 90%. After 8 h of NF, glyphosate recovery from the neutralization liquor reached 89.6% with an average permeate flux of around 4 L/(h m2). Moreover, membrane surface crystallization induced by concentration polarization probably caused the flux to decline during the process of batch NF.
Keywords: Glyphosate; Glycine-dimethylphosphit process; Nanofiltration;

Recycling of Cu powder from industrial sludge by combined acid leaching, chemical exchange and ferrite process by Yao-Jen Tu; Chien-Kuei Chang; Chen-Feng You; Jie-Chung Lou (981-985).
A method in combination of acid leaching, chemical exchange and ferrite process was applied to recycle copper and confer higher chemical stability to the sludge generated from etching process in printed circuit board industry. Ninety-five percent copper could be recycled in the form of powder from the sludge. Moreover, not only the wastewater after chemical exchange can be treated to fulfill the effluent standard, but also the sludge can satisfy the toxicity characteristic leaching procedure (TCLP) limits made by Taiwan's environmental protection administration.
Keywords: Printed circuit board industry sludge; Cu recycling; Acid leaching; Chemical exchange; Ferrite process;

We report an in situ soft chemical synthesis of a novel hybrid material, cellulose–nanoscale-manganese oxide composite (C–NMOC), and its application for Pb(II) removal from aqueous solutions. For comparison, detailed Pb(II) adsorption studies were also performed with nanoscale-manganese oxide powder (NMO), prepared through a similar route. Various spectroscopic and microscopic techniques were used to characterize the as-synthesized materials. X-ray photoelectron spectroscopic (XPS) measurements confirmed the existence of Mn(IV) phase in NMO whereas C–NMOC showed largely the Mn(III) phase. The existence and uniform distribution of manganese oxide in cellulose fiber materials was confirmed by SEM and EDAX analyses. The adsorption studies reveal that the Pb(II) uptake onto C–NMOC is a fast process and >90% of the uptake occurred within the first 10 min contact time. The Sips isotherm predicted the equilibrium data well and the maximum Pb(II) uptake capacity of C–NMOC (4.64% Mn loading) was estimeted to be 80.1 mg g−1. The Pb(II) adsorption capacity of C–NMOC (per gram of Mn present) was several times higher than commercial manganese oxide (β-MnO2) and at least twice larger than NMO. The experimental evidence reveals that physisorption plays a dominant role in Pb(II) adsorption by both NMO and C–NMOC.
Keywords: Adsorption; Cellulose; Hybrid materials; Lead; Nanoscale-manganese oxide;

Ligand-assisted preparation of highly active and stable nanometric Pd confined catalysts for deep catalytic oxidation of toluene by Chi He; Peng Li; Hailin Wang; Jie Cheng; Xinyan Zhang; Yufei Wang; Zhengping Hao (996-1003).
In this study, mesoporous SBA-15 supported Pd catalysts were synthesized through impregnation and grafting approaches. Moreover, the influences of different solvents (ethanol, H2O, tetrahydrofuran, dimethyl sulphoxide and N,N-dimethylformamide) on the dispersion of supported Pd nanoparticles were also systematically investigated. The prepared materials were comprehensively explored by various techniques, including XRD, EDS, ICP-OES, H2 chemisorption, N2 adsorption/desorption, TG-DSC, FT-IR, TEM and STEM. It is found that the traditional impregnation method has some disadvantages in obtaining highly dispersed Pd active phase. Whereas, the grafting method could highly disperse Pd nanoparticles within the mesoporous channels of support material, and the grafting procedure should be promising in designing highly dispersed Pd particles on the silica-based mesoporous materials. The catalyst prepared via the grafting procedure possesses much higher activity and selectivity than that prepared by impregnation method for deep catalytic oxidation of toluene.
Keywords: Ligand-assisted; Highly dispersed Pd; SBA-15; VOCs; Catalytic oxidation;

Flame retardant n-hexadecane/silicon dioxide (SiO2) composites as thermal energy storage materials were prepared using sol–gel methods. In the composites, n-hexadecane was used as the phase change material for thermal energy storage, and SiO2 acted as the supporting material that is fire resistant. In order to further improve flame retardant property of the composites, the expanded graphite (EG) was added in the composites. Fourier transformation infrared spectroscope (FT-IR), X-ray diffractometer (XRD) and scanning electronic microscope (SEM) were used to determine chemical structure, crystalloid phase and microstructure of flame retardant n-hexadecane/SiO2 composites, respectively. The thermal properties and thermal stability were investigated by a differential scanning calorimeter (DSC) and a thermogravimetric analysis apparatus (TGA), respectively. The SEM results showed that the n-hexadecane was well dispersed in the porous network of the SiO2. The DSC results indicated that the melting and solidifying latent heats of the composites are 147.58 and 145.10 kJ/kg when the mass percentage of the n-hexadecane in the composites is 73.3%. The TGA results showed that the loading of the EG increased the charred residue amount of the composites at 700 °C, contributing to the improved thermal stability of the composites. It was observed from SEM photographs that the homogeneous and compact charred residue structure after combustion improved the flammability of the composites.
Keywords: Composite materials; Sol–gel; Flame retardant property; Thermal properties; Thermal energy storage;

Liquid-phase decomposition of 4-nitrophenol (4-NP) and formation of hydrogen peroxide (H2O2) induced by contact glow discharge electrolysis (CGDE) were investigated. Experimental results showed that the decays of 4-NP and total organic carbon (TOC) obeyed the first-order and pseudo-first-order reaction kinetics, respectively. The major intermediate products were 4-nitrocatechol, hydroquinone, benzoquinone, hydroxyhydroquinone, organic acids and nitrite ion. The final products were carbon dioxide and nitrate ion. The initial formation rate of H2O2 decreased linearly with increasing initial concentration of 4-NP. Addition of iron ions, especially ferric ion, to the solution significantly enhanced the 4-NP removal due to the additional hydroxyl radical formation through Fenton's reaction. A reaction pathway is proposed based on the degradation kinetics and the distribution of intermediate products.
Keywords: Non-thermal plasma; p-Nitrophenol; Mechanism;

Treatment of smelting residue for arsenic removal and recovery of copper using pyro–hydrometallurgical process by Atsushi Shibayama; Yasushi Takasaki; Tongamp William; Atsushi Yamatodani; Yasunori Higuchi; Shigeru Sunagawa; Eiki Ono (1016-1023).
During pyro-metallurgical processing of non-ferrous metals, smelting residues such as smelter slag, flue gas, containing value metals and also harmful substances are inevitably generated as secondary product. For reduction of environmental loading and recovery of the value metals, such materials demand proper treatment options.In this research, some experimental steps were investigated to remove high arsenic (As: 19.5 wt%) and recover copper (Cu: 3.1 wt%) contained in such smelting residues. In the first-stage arsenic and other volatile materials were removed by pyro-metallurgical treatment and in the second-stage the treated residue from pyro-processing was treated in hydrometallurgical processing involving a two-stage leaching operation in H2SO4 solution to dissolve the metals followed by solvent extraction using LIX-84I as extractant to recover dissolved Cu in final leached solution.The results showed that over 90% of arsenic in smelting residue was removed by volatilization and recovered as As2O3 while copper content increased to 4.2 wt%. In the two-stage leaching process, first up to 90% of arsenic was selectively dissolved in 0.25 mol/L H2SO4 solution and second, the solids were further leached in 1.0 mol/L H2SO4 solution giving 85% of copper dissolution. Over 90% of copper dissolved into solution was recovered by solvent extraction. Finally over 99% of arsenic dissolved in the first-stage leach solution was co-precipitated with iron dissolved in second-stage leach solution after copper recovery.
Keywords: Smelting residue; Volatilization; Copper; Arsenic; Leaching; Solvent extraction;

Methyl ethyl ketone peroxide (MEKPO) is widely used in polymer industry. It is highly sensitive to heat, friction, shock, flame or other sources of ignition, causing risks in production, storage and transportation. In this article, MEKPO is synthesized at a high throughput with concentrated hydrogen peroxide in a microreactor for on-site and on-demand production. The influences of acid concentration, residence time, feeding rate and ratio, and reaction temperature on the yield and the mass fractions of residual methyl ethyl ketone (MEK) and active oxygen of the product are systematically investigated. Under optimized condition, the reaction is completed in a few seconds, and the product contains less than 2 wt% residual MEK and has a mass active oxygen fraction higher than 22 wt%, which meets the standard for industrial application.
Keywords: Microreactor; Peroxidation; Safety; Methyl ethyl ketone; Hydrogen peroxide;

Microcalorimetric and potentiometric titration studies on the adsorption of copper by P. putida and B. thuringiensis and their composites with minerals by Linchuan Fang; Peng Cai; Pengxiang Li; Huayong Wu; Wei Liang; Xingmin Rong; Wenli Chen; Qiaoyun Huang (1031-1038).
In order to have a better understanding of the interactions of heavy metals with bacteria and minerals in soil and associated environments, isothermal titration calorimetry (ITC), potentiometric titration and equilibrium sorption experiments were conducted to investigate the adsorption behavior of Cu(II) by Bacillus thuringiensis, Pseudomonas putida and their composites with minerals. The interaction of montmorillonite with bacteria increased the reactive sites and resulted in greater adsorption for Cu(II) on their composites, while decreased adsorption sites and capacities for Cu(II) were observed on goethite–bacteria composites. A gram-positive bacterium B. thuringiensis played a more important role than a gram-negative bacterium P. putida in determining the properties of the bacteria–minerals interfaces. The enthalpy changes (ΔH ads) from endothermic (6.14 kJ mol−1) to slightly exothermic (−0.78 kJ mol−1) suggested that Cu(II) is complexed with the anionic oxygen ligands on the surface of bacteria–mineral composites. Large entropies (32.96–58.89 J mol−1  K−1) of Cu(II) adsorption onto bacteria–mineral composites demonstrated the formation of inner-sphere complexes in the presence of bacteria. The thermodynamic data implied that Cu(II) mainly bound to the carboxyl and phosphoryl groups as inner-sphere complexes on bacteria and mineral–bacteria composites.
Keywords: Cu(II); Bacteria; Mineral; Composites; Adsorption;

Adsorption and magnetic removal of neutral red dye from aqueous solution using Fe3O4 hollow nanospheres by Mahmood Iram; Chen Guo; Yueping Guan; Ahmad Ishfaq; Huizhou Liu (1039-1050).
Fe3O4 hollow nanospheres were prepared via a simple one-pot template-free hydrothermal method and were fully characterized. These magnetic spheres have been investigated for application as an adsorbant for the removal of dye contaminants from water. Because of the high specific surface area, nano-scale particle size, and hollow porous material, Fe3O4 hollow spheres showed favorable adsorption behavior for Neutral red. Factors affecting adsorption, such as, initial dye concentration, pH and contact time were evaluated. Langmuir and the Freundlich adsorption isotherms were selected to explicate the interaction of the dye and magnetic adsorbant. The characteristic parameters for each isotherm have been determined. The overall trend followed an increase of the sorption capacity with increasing dye concentration with a maximum of 90% dye removal. The monolayer adsorption capacity of magnetic hollow spheres (0.05 g) for NR in the concentration range studied, as calculated from the Langmuir isotherm model at 25 °C and pH 6, was found to be 105 mg g−1. Adsorption kinetic followed pseudo-second-order reaction kinetics. Thermodynamic study showed that the adsorption processes are spontaneous and endothermic. The combination of the superior adsorption and the magnetic properties of Fe3O4 nanospheres can be useful as a powerful separation tool to deal with environmental pollution.
Keywords: Fe3O4 hollow nanospheres; Adsorption; Neutral red; Color removal; Adsorption isotherms;

Surface water samples were collected from 42 sampling sites throughout the upper Han River during the time period of 2005–2006. The concentrations of trace metals were determined using inductively coupled plasma-atomic emission spectrometry (ICP-AES) for the seasonal variability and preliminary risk assessment. The results demonstrated that concentrations of 11 heavy metals showed significant seasonality and most variables exhibited higher levels in the rainy season. Principal component analysis (PCA) and factor analysis (FA) revealed that variables governing water quality in one season may not be important in another season. Risk of metals on human health was then evaluated using Hazard Quotient (HQ) and carcinogenic risk, and indicated that As with HQ >1 and carcinogenic risk >10−4, was the most important pollutant leading to non-carcinogenic and carcinogenic concerns, in particular for children. The first five largest elements to chronic risks were As, Pb, V, Se and Sb, in the dry season, while they were As, V, Co, Pb and Sb in the rainy season. This assessment would help establish pollutant loading reduction goal and the total maximum daily loads, and consequently contribute to preserve public health in the Han River basin and develop water conservation strategy for the interbasin water transfer project.
Keywords: Han River; Trace metals; Risk assessment; Seasonal variations;

In the present study four new calix[4]arene amide ionophores (47) have been prepared by aminolysis of calix[4]arene diester (3) and investigated their extraction ability toward phosphate and dichromate anions at different pH. The 1H NMR data showed that the synthesized compounds exist in the cone conformation. Liquid–liquid extraction experiments have been performed to evaluate the dichromate and phosphate anions extraction efficiency of both calix[4]arene bearing amide-pyridinium units (47) and the calix[4]arene derivative bearing aminomethyl pyridinium units (8, 9). It was observed that, compounds 47 exhibited lower affinity toward phosphate ions than the calix[4]arene derivative bearing amine pyridinium units (8, 9). The extraction of phosphate and dichromate anions by these compounds indicates that the partially protonated pyridyl or amino groups play the major role for the formation of hydrogen bonds and electrostatic interactions.
Keywords: Calixarene; Dichromate anion; Phosphate anion; Liquid–liquid extraction;

Arsenic and lead (beudantite) contamination of agricultural rice soils in the Guandu Plain of northern Taiwan by Kai Ying Chiang; Kuo Chuan Lin; Sheng Chi Lin; Tsun-Kuo Chang; Ming Kuang Wang (1066-1071).
This study investigates the species of As and Pb (beudantite) residues present in the seriously contaminated agricultural rice soils of the Guandu Plain. Two pedons in the Guandu Plain agricultural soils, each pedon separated into five horizons (each of 20 cm) were collected for this study. Soil samples were packed into a column for leaching with simulated acid rains. Soil pH ranged from 5.1 to 7.1 with high base saturation. Soils can be classified as clay loam, mixed, thermic, Typic or Umbric Albaqualfs. The XRD analysis indicated the beudantite particles are present in clay fractions, showing high concentrations of As and Pb. This is because of 50–100 years ago irrigation water was introduced from Huang Gang Creek of hot springs containing high concentrations of As and Pb. Only low concentrations of As and Pb can be leached out with simulated acid rains (i.e., pHs 2 and 4), even through 40 pore volumes of leaching experiments. The sequential extraction experiments resulted in the high portions of As and Pb remaining in the amorphous, Fe and Al oxyhydroxides and residual fractions. Thus, the remediation of As and Pb in this agricultural rice paddy soils merits further study.
Keywords: Agricultural paddy soils; Beudantite; Hot springs; Sequential extraction;

As sorption data obtained from batch tests are often used to estimate pollutant transport in unsaturated soils, comparison between sorption data obtained in the two conditions is required to ensure a correct risk assessment. With this aim, radiostrontium and radiocesium apparent diffusion coefficients (D a) were quantified in nine unsaturated soils, and the derived distribution coefficients (K d) were compared with K d data from batch experiments.The D a(Sr) and the D a(Cs) ranged from 1.8 × 10−11 to 1.5 × 10−10  m2  s−1, and from 1.0 × 10−13 to 5.9 × 10−11  m2  s−1, respectively. The D a(Sr) varied according to both soil packing parameters and properties governing Sr interaction. For Cs, the soil sorption properties explained the variation on D a(Cs). The K d values derived from D a (from 0.014 to 1.8 L kg−1 for Sr; from 0.55 to 942 L kg−1 for Cs) were lower than from batch tests (from 1 to 97 L kg−1 for Sr; from 10 to 14,600 L kg−1 for Cs), thus indicating that batch data may not accurately describe radionuclide transport in unsaturated soils. However, the two sets of data correlated well, thus suggesting that radionuclide transport can be estimated from batch tests, which are faster than diffusion experiments.
Keywords: Radionuclide; Soil; Pollutant transport; Apparent diffusion coefficient; Distribution coefficient;

MAFRAM—A new fate and risk assessment methodology for non-volatile organic chemicals by Mohammad A. Batiha; Abdul Amir H. Kadhum; Marwan M. Batiha; Mohd S. Takriff; Abu Bakar Mohamad (1080-1087).
The main goal of this paper was to introduce an environmental fate and risk assessment methodology for comparing and establishing the general features of new and existing non-volatile organic chemicals (NVOCs) used in agricultural activities, based on simple and readily available properties. This methodology is a computer program called the multimedia agricultural fate and risk assessment model (MAFRAM). This model is a combination of the EQC-2V model, which describes the fate of NVOCs, with the ecological relative risk (EcoRR) approach, which assesses the ecotoxicological risk to agro-ecosystems. MAFRAM divides the agricultural environment into two main zones, which are the on- and off-farm zones. Each zone is subdivided into six compartments, including the air, water, soil, sediment, aboveground plants, and roots. The required input data are the chemical–physical properties of the pesticide, biota data, and environmental properties. The MAFRAM output includes the inter-compartmental transport and transfer rates, the primary loss mechanisms, chemical concentration, amount, residence time, and the rank of risk in each compartment. In addition, it can provide several secondary results. The MAFRAM application was illustrated using typical homogenous region properties and was run with an illustrative emission rate of 1 kg/h into air, using spinosad as a case study.
Keywords: Agro-ecosystem; Chemical comparing and ranking; Environmental fate; Risk assessment; NVOCs;

A technology of obtaining active carbon from plum stones by chemical activation with KOH is described. The effect of carbonisation temperature as well as activation procedure on the textural parameters, acid–base character of the surface and sorption properties of active carbons has been checked. The sorption properties of the activated carbons obtained were characterised by determination of nitrogen dioxide adsorption in dry and wet conditions.The final products were microporous activated carbons of well-developed surface area varying from 2174 to 3228 m2/g and pore volume from 1.09 to 1.61 cm3/g, showing different acid–base character of the surface. The results obtained in our study have proved that a suitable choice of the carbonisation and activation procedure for plum stones can produce activated carbons with high capacity of nitrogen dioxide, reaching to 67 and 42 mg NO2/g in dry and wet conditions, respectively. The results of our study have also shown that the adsorption ability of carbonaceous sorbents depends both on the method of preparation as well as on the textural parameters and acid–base properties of their surface.
Keywords: Plum stones; Carbonisation; Chemical activation; Carbonaceous adsorbents; NO2 adsorption/reduction;

Inside the removal of lead(II) from aqueous solutions by De-Oiled Allspice Husk in batch and continuous processes by J. Cruz-Olivares; C. Pérez-Alonso; C. Barrera-Díaz; G. López; P. Balderas-Hernández (1095-1101).
A new adsorbent material for removing lead ions from aqueous solutions has been investigated. The residue of the allspice extraction process (De-Oiled Allspice Husk) was used on the removal of Pb(II) from water solutions. The lead sorption capacity of De-Olied Allspice Husk (DOAH) was studied in batch and continuous processes. It was found that percentage removals of Pb(II) depend on the pH and the initial lead concentrations. The Pb(II) uptake process was maximum at pH 5 in a range concentrations of 5–25 mg L−1.The overall sorption process was well described by the pseudo-second-order kinetic model under conditions of pH 5 (0.1 g adsorbent per 100 mL of contaminated solution) 0.001 mass/volume ratio and 25 °C. The sorption capacity of lead(II) onto DOAH in batch process was 5.00, 8.02, 11.59, 15.23 and 20.07 mg g−1, when the concentration solutions were 5, 10, 15, 20 and 25 mg L−1 respectively. These values are lower than obtained in continuous process, where lead was removed by 95% and the experimental results were appropriately fitted by the Yoon–Nelson model. X-ray photoelectron spectroscopy (XPS) provides information regarding the interactions between lead ions and the adsorbent surface indicating that the formation of 2 complexes depends on the functional groups associated.
Keywords: Biosorption; Heavy metals; Pimenta dioica; Complexes; XPS;

Synthesis of monoclinic structured BiVO4 spindly microtubes in deep eutectic solvent and their application for dye degradation by Wei Liu; Yaqin Yu; Lixin Cao; Ge Su; Xiaoyun Liu; Lan Zhang; Yonggang Wang (1102-1108).
Monoclinic structured spindly bismuth vanadate microtubes were fabricated on a large scale by a simple ionothermal treatment in the environment-friendly green solvent of urea/choline chloride. The as-prepared samples were characterized by XRD, SEM, TEM, IR and their photocatalytic activity was evaluated by photocatalytic decolorization of rhodamine B aqueous solution under visible-light irradiation. As-obtained BiVO4 microtubes exhibit the spindly shape with a side length of ca. 800 nm and a wall thickness of ca. 100 nm. The opening of these microtubes presents a saw-toothed structure, which is seldom in other tube-shaped materials. The formation mechanism of the spindly microtubes is ascribed to the complex cooperation of the reaction–crystallization process controlled by BiOCl and the nucleation-growth process of nanosheets induced by solvent molecules attached on the surface of microtubes. Such spindly microtubes exhibit much higher visible-light photocatalytic activity than that of bulk BiVO4 prepared by solid-state reaction, possibly resulting from their large surface area and improved crystallinity.
Keywords: Bismuth vanadate; Deep eutectic solvent; Microtube; Photocatalyst;

Solubilization of dibutyltin dichloride with surfactant solutions in single and mixed oil systems by S. Damrongsiri; C. Tongcumpou; P. Weschayanwiwat; D.A. Sabatini (1109-1114).
The harmful effects of organometallic compounds and their metabolites on the environment and human health require the development of more effective remediation methods. Surfactant enhanced remediation has been considered as a potential method for the removal of organometallic compounds; however, additional understanding is needed about the solubilization processes of these compounds. The surfactant enhanced solubilization of dibutyltin dichloride (DBT), an organometallic compound, was the focus of this research. In addition, the synergistic effects of DBT solubilization in perchloroethylene (PCE) and decane mixtures were evaluated. The results indicate that PCE and decane were solubilized into the core of these surfactant micelles in both single and mixed oil systems. DBT solubilization was limited when DBT alone was present (single oil system), and the nature of the solubilization isotherm suggests that DBT solubilization tended to occur near the micelle surface in a single oil system. DBT solubilization was found to increase when present in the PCE and decane oil mixture. PCE and decane may have facilitated the solubilization of DBT because they were solubilized in the micelle core. From this study, it may be concluded that the DBT behaves like polar oil such as dodecanol, having properties of a polar organic compound.
Keywords: Organometal; Dibutyltin dichloride; Perchloroethylene; Solubilization;

Adsorption of polycyclic aromatic hydrocarbons from water using petroleum coke-derived porous carbon by Mingjiang Yuan; Shitang Tong; Suoqi Zhao; Charles Q. Jia (1115-1120).
Porous carbons were prepared from petroleum coke by KOH chemical activation, characterized and used as adsorbents for uptaking a mixture of polycyclic aromatic hydrocarbons (PAHs): naphthalene, fluorene, phenanthrene, pyrene and fluoranthene from aqueous solutions. The specific surface area (SSA) of these carbons ranges from 562 to 1904 m2/g, while their point of zero charge (pHPZC) varies from 2.6 to 8.8. The equilibrium adsorption of PAHs on all four carbons follows the non-linear Freundlich equation well. For any given PAH in the group, the adsorption capacity parameter K f , increases with the SSA and pHPZC of the carbons, confirming the roles of dispersive interactions. For any given carbon, the value of K f follows the order of naphthalene > fluorene > phenanthrene > pyrene. This dependence of K f on molecular size suggests a certain degree of molecular sieving behavior of these carbons toward large PAHs. Under the condition studied, the uptake process is likely controlled by diffusive transport processes. And, it is unlikely that the competitive adsorption played any important roles in determining equilibrium adsorption of the mixed PAHs. Overall, the petroleum coke-derived porous carbon is very effective in adsorbing these PAHs.
Keywords: Polycyclic aromatic hydrocarbons; Porous carbon; Adsorption; Mechanism;

Genomic expression profiles in liver of mice exposed to purified terephthalic acid manufacturing wastewater by Zongyao Zhang; Liping Ma; Xu-Xiang Zhang; Weixin Li; Yan Zhang; Bing Wu; Liuyan Yang; Shupei Cheng (1121-1126).
DNA micorarray was used to analyze hepatic transcriptional profile of male mice (Mus musculus) after 35-d intragastric perfusion treatment with purified terephthalic acid (PTA) manufacturing wastewater. Haematological analysis demonstrated that the levels of glutamyl transferase and lactate dehydrogenase in serum were significantly decreased, and DNA microarray showed that a total of 306 genes were differentially expressed in PTA wastewater-treated mice. According to Kyoto encyclopedia of genes and genomes pathway database, the differentially expressed genes were mainly grouped to metabolic pathways (58 genes) and biological processes (101 genes). PTA wastewater had significant impacts upon metabolisms of lipid, carbohydrate, amino acid, vitamin and nucleotide. Several signal transduction pathways are most susceptible to PTA wastewater, including mitogen-activated protein kinases, Janus kinase/signal transducers and activators of transcription and calcium signaling pathways. Potential public health problems may arise from the discharge of PTA wastewater into the environment.
Keywords: Purified terephthalic acid; Industrial wastewater; Genomic toxicity; Microarray;

The photochemical degradation and estrogenicity removal of 17α-ethinylestradiol in aqueous solutions was investigated via ultraviolet (UV) photolysis and UV/H2O2 process with a low-pressure UV lamp. The results indicated that the kinetics of both oxidation processes well fitted the pseudo-first-order kinetics. EE2 can be partially removed by UV radiation alone with kinetic constants increasing from 0.0054 to 0.2753 min−1 with the UV intensity increase. The EE2 degradation rate enhanced from 0.0364 to 0.0684 min−1 when H2O2 was combined with the photolysis process (UV/H2O2), even though EE2 was not oxidized when same amounts of H2O2 existed in the aqueous solutions. The kinetic parameters of pseudo-first-order kinetics showed positive correlation to UV intensity and also H2O2 concentration, however negative to the initial EE2 concentration. A regression model was developed for pseudo-first-order rate constant as a function of the UV intensity, H2O2 concentration and initial EE2 concentration, which could be used to estimate the EE2 degradation rate at various operational conditions. The yeast estrogen screen (YES) was employed to evaluate the estrogenicity of photolytic water samples. Results showed that more than 95% of the estrogenicity was removed after 40 min irradiation and the parent compound EE2 was mainly responsible for the observed estrogenicity.
Keywords: 17α-Ethinylestradiol; UV/H2O2 process; Kinetic model; Rate constants; Yes assay;

Present study deals with the utilization of an agro-industrial waste wheat bran for the remediation of selenium species, Se(IV) and Se(VI) by continuous up-flow fixed-bed column system. Laboratory-scale column tests were performed to determine potentiality of wheat bran at various bed height, flow rates and initial metal ion concentration and it was found to be very potential biosorbent as it showed good sorption capacities of 72.54 μg/g and 62.51 μg/g for Se(IV) and Se(VI) respectively. Different models like Bed Depth Service Time (BDST), Thomas and Yoon–Nelson were applied to the experimental sorption data. The data showed very good fit to BDST model and sorption capacities (N o) computed using BDST model were 26,664 μg/L and 26,400 μg/L for Se(IV) and Se(VI) respectively. Also Yoon–Nelson model was found to show good agreement with the experimental kinetic results as compared to the Thomas model. Wheat bran was amenable to efficient regeneration with 10% NaOH. The biosorbent retained most of its original uptake capacity over three cycles of use. The excellent reusability of the biosorbent could lead to development of a viable metal remediation technology. Life factor calculation revealed that biosorbent bed will have sufficient capacity to avoid breakthrough at time t  = 0 up to 12.17 cycles for Se(IV) and 6.28 cycles for Se(VI) and bed would be completely exhausted after 56.89 cycles for Se(IV) and 18.73 cycles for Se(VI).
Keywords: Selenium; Wheat bran; Biosorptive remediation; Column; Regeneration;

The microwave enhanced advanced oxidation process (MW/H2O2-AOP) was used to treat municipal sewage sludge for solids disintegration, nutrient solubilization, with an emphasis on pathogen destruction and regrowth. Pathogen reduction, in terms of fecal coliform concentrations were found below detection limit (1000 CFU/L) immediately after treatment when sludge was treated at 70 °C with more than 0.04% of H2O2 (w/w). Significant regrowth of fecal coliforms was observed for the treated samples after 72 h. However, no regrowth was observed for samples treated at 70 °C with 0.08% H2O2 or higher, suggesting a complete elimination of fecal coliforms. The range of hydrogen peroxide used did not have a significant effect on orthophosphate release regardless of temperature. Ammonia release at these low temperatures was found to be insignificant. The soluble chemical oxygen demand increased with an increase of hydrogen peroxide dosage at 70 °C. However, there was no clear trend of soluble chemical oxygen demand over varying hydrogen peroxide dosage at 55 °C. The MW/H2O2-AOP is a novel process for the pasteurization and stabilization of sewage sludge to meet and maintain Class A biosolids criteria.
Keywords: Microwave radiation; Disinfection; Fecal coliforms regrowth; Nutrient release;

Barium uptake by maize plants as affected by sewage sludge in a long-term field study by Thiago Assis Rodrigues Nogueira; Wanderley José deMelo; Ivana Machado Fonseca; Marcos Omir Marques; Zhenli He (1148-1157).
A long-term experiment was carried out under field conditions in Jaboticabal, SP, Brazil, with the objective of evaluating the concentration of Ba in soil and in maize plants grown in a soil treated with sewage sludge for nine consecutive years. During 2005/2006, maize was used as test plants and the experimental design was in randomized complete blocks with four treatments and five replicates. Treatments consisted of: 0.0, 45.0, 90.0 and 127.5 t ha−1 sewage sludge (dry basis). Sewage sludge application increased soil Ba concentration. Barium accumulated in the parts of maize plants were generally affected by the successive applications of sewage sludge to the soil. However, the concentration of Ba in maize grain did not exceed the critical levels of Ba for human consumption. Sewage sludge applied to soil for a long time did not affect dry matter and grain production, nevertheless had the similar effect of mineral fertilization.
Keywords: Zea mays L.; Biosolid; Heavy metal; Urban waste; Food contamination;

Construction of an artificial microalgal-bacterial consortium that efficiently degrades crude oil by X. Tang; L.Y. He; X.Q. Tao; Z. Dang; C.L. Guo; G.N. Lu; X.Y. Yi (1158-1162).
Four oil component-degrading bacteria and one oil-tolerant microalgae, Scenedesmus obliquus GH2, were used to construct an artificial microalgal-bacterial consortium for crude-oil degradation. The bacterial strains included Sphingomonas GY2B and Burkholderia cepacia GS3C, along with a mixed culture, named GP3, containing Pseudomonas GP3A and Pandoraea pnomenusa GP3B. GY2B could only degrade polycyclic aromatic hydrocarbons, GS3C was able to degrade aliphatic chain hydrocarbons, and GP3 could utilize both saturated and aromatic hydrocarbons. In combination with unialgal or axenic algae, the bacteria showed different effects on oil degradation. Unialgal GH2 was not suitable for the consortium construction, as it could not cooperate well with GS3C and GP3. The axenic GH2 exhibited no oil-degrading ability; however, it significantly promoted the degradation ability of the oil component-degrading bacteria, especially for degrading biorefractory polycyclic aromatic hydrocarbons. Axenic S. obliquus GH2, combined with the four bacteria mentioned above, formed an optimal algal-bacterial consortium. The artificial consortium demonstrated an elevated efficiency in degrading both aliphatic and aromatic hydrocarbons of crude oil.
Keywords: Algal-bacterial consortium; Scenedesmus obliquus; Oil component-degrading bacteria; Crude oil;

Effect of pine bark and compost on the biological denitrification process of non-hazardous landfill leachate: Focus on the microbiology by Cristina Trois; Frédéric Coulon; Cécile Polge de Combret; Jean M.F. Martins; Laurent Oxarango (1163-1169).
In an attempt to optimize the cost-efficiency of landfill leachate treatment by biological denitrification process, our study focused on finding low-cost alternatives to traditional expensive chemicals such as composted garden refuse and pine bark, which are both available in large amount in South African landfill sites. The overall objective was to assess the behaviour of the bacterial community in relation to each substrate while treating high strength landfill leachates. Denitrification processes in fixed bed reactors were simulated at laboratory scale using anaerobic batch tests with immature compost and pine bark. High strength leachate was simulated using a solution of water and nitrate at a concentration of 500 mg l−1. Results suggest that pine bark released large amounts of phenolic compounds and hydroxylated benzene rings, which both can delay the acclimatization time and inhibit the biological denitrification (only 30% efficiency). Furthermore, presence of potential pathogens like Enterobacter and Pantoea agglomerans prevents the applicability of the pine bark in full-scale operations. On the other hand, lightly composted garden refuse (CGR) offered an adequate substrate for the formation of a biofilm necessary to complete the denitrification process (total nitrate removal observed within 7 days). CGR further contributed to a rapid establishment of an active consortium of denitrifiers including Acinetobacter, Rhizobium, Thermomonas, Rheinheimera, Phaeospirillum and Flavobacterium. Clearly the original composition, nature, carbon to nitrogen ratio (C/N) and degree of maturity and stability of the substrates play a key role in the denitrification process, impacting directly on the development of the bacterial population and, therefore, on the long-term removal efficiency.
Keywords: Denitrification; Landfill leachate; Compost; Pine bark; Microbial diversity;

The further development of Fe0-based remediation technology depends on the profound understanding of the mechanisms involved in the process of aqueous contaminant removal. The view that adsorption and co-precipitation are the fundamental contaminant removal mechanisms is currently facing a harsh scepticism. Results from electrochemical cementation are used to bring new insights in the process of contaminant removal in Fe0/H2O systems. The common feature of hydrometallurgical cementation and metal-based remediation is the heterogeneous nature of the processes which inevitably occurs in the presence of a surface scale. The major difference between both processes is that the surface of remediation metals is covered by layers of own oxide(s) while the surface of the reducing metal in covered by porous layers of the cemented metal. The porous cemented metal is necessarily electronic conductive and favours further dissolution of the reducing metal. For the remediation metal, neither a porous layer nor a conductive layer could be warrant. Therefore, the continuation of the remediation process depends on the long-term porosity of oxide scales on the metal surfaces. These considerations rationalized the superiority of Fe0 as remediation agent compared to thermodynamically more favourable Al0 and Zn0. The validity of the adsorption/co-precipitation concept is corroborated.
Keywords: Adsorption; Cementation; Co-precipitation; Surface scale; Zerovalent iron;

Elimination of carbamazepine by repeated treatment with laccase in the presence of 1-hydroxybenzotriazole by Takayuki Hata; Hideaki Shintate; Shingo Kawai; Hideo Okamura; Tomoaki Nishida (1175-1178).
Carbamazepine (CBZP) is used as an antiepileptic drug and is highly persistent. In this study, CBZP was treated with laccase from white rot fungus Trametes versicolor in the presence of a redox mediator 1-hydroxybenzotriazole (HBT). A single treatment with laccase and HBT eliminated CBZP by about 22% after 24 h, and repeated treatments with laccase and HBT, which were added to the reaction mixture every 8 h, helped eliminate about 60% of CBZP after 48 h. This suggests that repeated treatment is effective in eliminating CBZP. Mass spectrometric analyses demonstrated that two degradation products of CBZP, 10,11-dihydro-10,11-epoxycarbamazepine and 9(10H)-acridone, were formed via repeated treatment with laccase and HBT.
Keywords: Carbamazepine; Elimination; Ligninolytic enzymes; Laccase; 1-Hydroxybenzotriazole;

Floating aerial blood mists in the operating room by Kohji Ishihama; Satoshi Sumioka; Koichi Sakurada; Mikihiko Kogo (1179-1181).
High-speed surgical instruments and electric coagulator devices produce contaminated particles and aerosols. This study aimed to investigate the presence of blood-contaminated aerosol in a class 6 and 7 (ISO14644-1) operating room environment. Test filters were fitted to the extract ducts of a standard central air conditioning system, and were left in place for 1, 2, or 4 weeks. In a separate experiment to analyze contributing factors, the test filters were changed following every operation. Green dots showing a reaction with leucomalachite green method were counted. In the accumulation experiment, the number of positive dots tended to increase over time (26, 60, and 143 dots after 1, 2, and 4 weeks, respectively). The distance between the test filters and surgical field ranged from 3.8 to 4.6 m. In our analysis of contributing factors, positive filters were present in 9 of 10 surgeries that used high-speed instruments and in 16 of 17 using electric coagulator devices. Surgical procedures performed with these devices produce aerosolized blood, which can float in the operating room. Thus, caution must be taken by perioperative staff, such as anaesthetists and surgical assistants, as well as by surgeons.
Keywords: Blood-contaminated aerosol; Operating room; Airborne infection; Electric coagulator; High-speed instrument;