Personal Research Database

Full Text: 2009\J Haz Mat167, 406.pdf

Abstract: Experimental measurements have been made on the batch ion exchange of Ca(II) and Mg(II) from potassium chromate solution using cation exchanger of Amberlite IRC 748 as K⁺ form. The ion exchange behavior of two alkaline-earth metals on the resin, depending on contact time, pH, temperature and resin dosage was studied. The adsorption isotherms were described by means of the Langmuir and Freundlich isotherms. For Ca(II) ion, the Langmuir model represented the adsorption process better than the Freundlich model. The maximum ion exchange capacity was found to be 47.21 mg g^-1 for Ca(II) and 27.70 mg g^-1 for Mg(II). The kinetic data were tested using Lagergren-first-order and pseudo-second-order kinetic models. Kinetic data correlated well with the pseudo-second-order kinetic model, indicating that the chemical adsorption was the rate-limiting step. Various thermodynamic parameters such as Gibbs free energy (Delta G degrees), enthalpy (Delta H degrees) and entropy (Delta S degrees) were also calculated. These parameters showed that the ion exchange of Ca(II) and Mg(II) from potassium chromate solution was feasible, spontaneous and endothermic process in nature. The activation energy of ion-exchange (E-a) was determined as 12.34 kJ mol^-1 for Ca(II) and 9.865 kJ mol^-1 for Mg(II) according to the Arrhenius equation. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Activation, Activation Energy, Adsorption, Adsorption Characteristics, Adsorption Isotherms, Aqueous-Solution, Batch, Batch Adsorption, Behavior, Biosorption, Capacity, Cation, Cation Exchanger, Chemical, Chromate, Cr(VI), Data, Endothermic, Energy, Enthalpy, Entropy, Equilibrium Parameters, Freundlich, Freundlich Model, Gibbs Free Energy, Iminodiacetate Resin, Ion Exchange, Ion Exchange Capacity, Ion-Exchange, Ion-Exchange Resin, Ionexchange, Isotherms, Kinetic, Kinetic Model, Kinetic Models, Kinetics, Langmuir, Langmuir and Freundlich Isotherms, Langmuir Model, Metals, Model, Models, Ni²⁺, Part I, pH, Potassium, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Kinetic Model, Rate Limiting Step, Rate-Limiting Step, Removal, Resin, Rights, Solution, Temperature, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Waste-Water

? Freitas, O., erue-Matos, C. and Boaventura, R. (2009), Optimization of Cu(II) biosorption onto Ascophyllum nodosum by factorial design methodology. Journal of Hazardous Materials, 167 (1-3), 449-454.

Full Text: 2009\J Haz Mat167, 449.pdf

Abstract: A Box-Behnken factorial design coupled with surface response methodology was used to evaluate the effects of temperature, pH and initial concentration in the Cu(II) sorption process onto the marine macro-algae Ascophyllum nodosum. The effect of the operating variables on metal uptake capacity was studied in a batch system and a mathematical model showing the influence of each variable and their interactions was obtained. Study ranges were 10-40°C for temperature, 3.0-5.0 for pH and 50-150 mg L^-1 for initial Cu(II) concentration. Within these ranges, the biosorption capacity is slightly dependent on temperature but markedly increases with pH and initial concentration of Cu(II). The uptake capacities predicted by the model are in good agreement with the experimental values. Maximum biosorption capacity of Cu(II) by A. nodosum is 70 mg g^-1 and corresponds to the following values of those variables: temperature = 40°C, pH = 5.0 and initial Cu(II) concentration = 150 mg L^-1. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Aqueous-Solutions, Ascophyllum Nodosum, Batch System, Biosorption, Box-Behnken, Cadmium Biosorption, Capacity, Cu(II), Desorption, Elsevier, Equilibrium, Factorial Design, Heavy-Metal Biosorption, Marine-Algae, Mathematical Model, Metal, Optimization, pH, Pretreated Biomass, Response Surface Methodology, Response-Surface Methodology, Sargassum sp Biomass, Sorption, System, Temperature

? Kong, B., Tang, B.Y., Liu, X.Y., Zeng, X.D., Duan, H.Y., Luo, S.L. and Wei, W.Z. (2009), Kinetic and equilibrium studies for the adsorption process of cadmium(II) and copper(II) onto Pseudomonas aeruginosa using square wave anodic stripping voltammetry method. Journal of Hazardous Materials, 167 (1-3), 455-460.

Full Text: 2009\J Haz Mat167, 455.pdf

Abstract: A novel method for the simultaneous determination of cadmium(II) and copper(II) during the adsorption process onto Pseudomonas aeruginosa was developed. The concentration of the free metal ions was successfully detected by square wave anodic stripping voltammetry (SWASV) on the mercaptoethane sulfonate (MES) modified gold electrode, while the P. aeruginosa was efficiently avoided approaching to the electrode surface by the MES monolayer. and the anodic stripping peaks of Cd²⁺ and Cu²⁺ appear at -0.13 and 0.34V respectively, at the concentration range of 5-50 mu M, the peak currents of SWASV present linear relationships with the concentrations of cadmium and copper respectively. As the determination of Cd²⁺ and Cu²⁺ was in real time and without pretreatment, the kinetic characteristics of the adsorption process were studied and all the corresponding regression parameters were obtained by fitting the electrochemical experimental data to the pseudo-second-order kinetic model. Moreover, Langmuir and Freundlich models well described the biosorption isotherms. and there were some differences in the amount of metal ion adsorbed at equilibrium (q(e)) and other kinetics parameters when the two ions coexisted were compared with the unaccompanied condition, which were also discussed in this paper. The proposed electrode system provides excellent platform for the simultaneous determination of trace metals in complex biosorption process. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Anodic Stripping Voltammetry, Aqueous-Solution, Biosoption, Biosorption, Biosorption Isotherms, Cadmium, Cadmium(II), Cd²⁺, Characteristics, Concentration, Copper, Copper(II), Cu²⁺, Currents, Data, Equilibrium, Equilibrium Studies, Experimental, Freundlich, Gold, Gold Electrodes, Heavy-Metals, Ion, Ions, Isotherms, Kinetic, Kinetic Model, Kinetics, Kinetics Parameters, Langmuir, Lead, Leaves, ME, Mercaptoethane Sulfonate, Metal, Metal Ions, Metals, Model, Models, Modified, Monolayer, P, Preconcentration, Pretreatment, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Kinetic Model, Pseudomonas Aeruginosa, Regression, Rights, Samples, Simultaneous Determination, Stripping, Surface, Trace Metals, Voltammetry

? Alyüz, B. and Veli, S. (2009), Kinetics and equilibrium studies for the removal of nickel and zinc from aqueous solutions by ion exchange resins. Journal of Hazardous Materials, 167 (1-3), 482-488.

Full Text: 2009\J Haz Mat167, 482.pdf

Abstract: Removal of heavy metals from wastewater is obligatory in order to avoid water pollution. In the present study, performance of Dowex HCR S/S cation exchange resin was evaluated for removal of nickel and zinc from aqueous solutions. Batch shaking adsorption experiments were performed in order to examine the effects of pH, dosage of resin and contact time on removal process. It was observed that more than 98% removal efficiency was achieved under optimal conditions for nickel and zinc. The experimental equilibrium data were tested for the Langmuir, Freundlich and Temkin isotherms. Correlation coefficients indicate the following order to fit isotherms: Langmuir > Freundlich > Temkin for both nickel and zinc ions. Pseudo-first- and -second-order kinetic models were used for describing kinetic data. It was determined that removal of Ni²⁺ and Zn²⁺ was well-fitted by second-order reaction kinetic. Furthermore, separation factors and distribution coefficients of nickel and zinc for Dowex HCR S/S were calculated. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Aqueous Solutions, Cation, Cation Exchange, Chromium, Copper, Data, Distribution, Dye, Efficiency, Equilibrium, Equilibrium Studies, Experimental, Experiments, Fly-Ash, Freundlich, Heavy Metals, Heavy-Metal Ions, Ion Exchange, Ion Exchange Resins, Ion-Exchange, Ions, Isotherms, Kinetic, Kinetic Models, Kinetics, Langmuir, Lead, Metals, Models, Ni²⁺, Nickel, Performance, pH, Pollution, Removal, Removal Efficiency, Resin, Resins, Rights, Second Order, Second-Order, Separation, Separation Factors, Solutions, Waste-Water, Wastewater, Water, Water Pollution, Zeolite, Zinc, Zn²⁺

? Agouborde, L. and Navia, R. (2009), Heavy metals retention capacity of a non-conventional sorbent developed from a mixture of industrial and agricultural wastes. Journal of Hazardous Materials, 167 (1-3), 536-544.

Full Text: 2009\J Haz Mat167, 536.pdf

Abstract: Zinc and copper removal from aqueous solutions using brine sediments (industrial residue), sawdust (agricultural residue) and the mixture of both materials has been researched through batch and column tests. Brine sediments were found to be mainly constituted by halite and calcite, while its main cations exchangeable were sodium, calcium, magnesium and potassium. In sawdust the main exchangeable cations detected were calcium, magnesium, sodium and potassium.

FT-IR spectra of sawdust and brine sediment-sawdust mixture showed that brine sediments produced important changes in carboxylic, alcoholic and phenolic groups present in the sawdust.

The maximum zinc adsorption capacity was found to be 4.85, 2.58 and 5.59 mg/g using an adsorbent/solution ratio of 1/40, for brine sediments, sawdust and the mixture, respectively. For copper, the maximum adsorption capacity was found to be 4.69, 2.31 and 4.33 mg/g, using adsorbent/solution ratios of 1/40, for brine sediments, sawdust and the mixture, respectively. Maximum copper adsorption capacity of the mixture, on the contrary to zinc adsorption, was lightly inferior to maximum adsorption capacity obtained in brine sediments.

Adsorption isotherms data adjusted better to the Langmuir model. Additionally, columns reached the saturation point at 690 min for zinc and 360 min for copper. The main mechanism involved in the removal of both metals may be the ionic exchange between sodium and calcium ions present in brine sediments and H+ present in functional groups of sawdust. The use of brine sediments, sawdust and their mixture, presents an interesting option both, for wastewater decontamination (as a possible non-conventional sorbent for the removal of heavy metals) and as a waste recycling option. (C) 2009

Keywords: Zinc, Copper, Wastewater Treatment, Brine Sediments, Sawdust, FT-IR Spectroscopy, Aqueous-Solutions, Adsorption Characteristics, Ion-Exchange, Fly-Ash, Removal, Copper, Sawdust, Water, Cu(II)

? Saponaro, S., Negri, M., Sezenna, E., Bonomo, L. and Sorlini, C. (2009), Groundwater remediation by an in situ biobarrier: A bench scale feasibility test for methyl tert-butyl ether and other gasoline compounds. Journal of Hazardous Materials, 167 (1-3), 545-552.

Full Text: 2009\J Haz Mat167, 545.pdf

Abstract: Most gasoline contains high percentages of methyl tert-butyl ether (MTBE) as an additive. The physicochemical properties of this substance (high water solubility, low sorption in soil) result in high mobility and dissolved concentrations in soil. In situ permeable biological barriers (biobarriers, BBs) can remediate MTBE polluted groundwater by allowing pure cultures or microbial consortia to degrade MTBE when aerobic conditions are present, either by direct metabolism or cometabolism. Lab-scale batch and column tests were carried out to assess a selected microbial consortium in biodegrading MTBE and other gasoline compounds (benzene B, toluene T, ethylbenzene E, xylenes X) and to measure the parameters affecting the efficacy of a BB treatment of polluted groundwater. During the aerobic phase of the batch tests, the simultaneous biodegradation of MTBE, tert-butyl alcohol (TBA), B, T, E and o-X was observed. The rapid biodegradation of BTEXs resulted in decreased oxygen availability, but MTBE degradation was nevertheless measured in the presence of BTEXs. Stationary concentrations of MTBE and TBA were measured when anoxic conditions occurred in the systems. Values for a first order kinetic removal process were obtained for MTBE (0.031 +, - 0.001 d(-1)), B (0.045 +, - 0.002 d(-1)) and T (0.080 +, - 0.004 d(-1)) in the inoculated column tests. The estimate of the BB design parameters suggested that inoculation could significantly modify (double) the longitudinal dispersivity value of the biomass support medium. No effect was observed in the retardation factors for MTBE, B and T. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Alcohol, Barriers, Batch, Biodegradation, Biological Treatment, Column, Design, Design Parameters, Efficacy, Feasibility, First Order, Gasoline, Groundwater, Groundwater Remediation, Kinetic, Kinetics, MTBE, MTBE Biodegradation, Reactive Barrier, Reactors, Remediation, Removal, Soil, Solubility, Sorption, TBA, Treatment

? Jing, X.S., Liu, F.Q., Yang, X., Ling, P.P., Li, L.J., Long, C. and Li, A.M. (2009), Adsorption performances and mechanisms of the newly synthesized N,N’-di (carboxymethyl) dithiocarbamate chelating resin toward divalent heavy metal ions from aqueous media. Journal of Hazardous Materials, 167 (1-3), 589-596.

Full Text: 2009\J Haz Mat167, 589.pdf

Abstract: N,N’-di (carboxymethyl) dithiocarbamate chelating resin (PSDC) was synthesized by anchoring the chelating agent of N,N’-di (carboxymethyl) dithiocarbamate to the chloromethylated PS-DVB (Cl-PS-DVB) matrix as a new adsorbent for removing divalent heavy metal ions from waste-stream. The physicochemical structures of Cl-PS-DVB and PSDC were elaborately characterized using Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), and were further morphologically characterized using BET and BJH methods. The adsorption performances of PSDC towards heavy metals such as Cu(II), Pb(II) and Ni(II) were systematically investigated, based upon which the adsorption mechanisms were deeply exploited. For the above target, the classic batch adsorption experiments were conducted to explore the kinetics and isotherms of the removal processes with pH-value, initial concentration, temperature, and contact time as the controlling parameters. The kinetic and isotherm data could be well elucidated with Lagergren-second-order equation and Langmuir model respectively. The strong affinity of PSDC toward these target soft acids could be well demonstrated with the electrostatic attraction and chelating interaction caused by IDA moiety and sulphur which were namely soft bases on the concept of hard and soft acids and bases (HASB). Thermodynamic parameters, involving Delta H degrees, Delta S degrees and Delta G degrees were also calculated from graphical interpretation of the experimental data. The standard heats of adsorption (Delta H degrees) were found to be endothermic and the entropy change values (Delta S degrees) were calculated to be positive for the adsorption of Cu(II), Pb(II) and Ni(II) ions onto the tested adsorbents. Negative values of Delta G degrees indicated that adsorption processes for all tested metal ions onto PSDC were spontaneous. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorbent, Adsorption, Analysis, Batch Adsorption, Copolymer, Cu(II), Divalent Heavy Metal Ions, Exchange, Experimental, Ftir, Heavy Metal, Heavy Metal Ions, Heavy Metals, Iminodiacetic Acid, Interpretation, Ions, Isotherm, Isotherms, Kinetic, Kinetics, Langmuir, Langmuir Model, Mechanisms, Metal, Metal Ions, Metals, Methacrylate), Model, N,N’-Di (Carboxymethyl) Dithiocarbamate Chelating Resin, Pb(II), pH Value, Polymers, Preconcentration, Removal, Separation, Synthetic Resin, Thermodynamic, Thermodynamic Parameters, Water

? Vega, F.A., Matías, J.M., Andrade, M.L., Reigosa, M.J. and Covelo, E.F. (2009), Classification and regression trees (CARTs) for modelling the sorption and retention of heavy metals by soil. Journal of Hazardous Materials, 167 (1-3), 615-624.

Full Text: 2009\J Haz Mat167, 615.pdf

Abstract: The sorption and retention of mixtures of heavy metals by soil is a complex process that depends on both soil properties and competition between metals for sorption sites. In this study, the sorption and retention of mixtures of Cd, Cr, Pb, Cu, Zn and Ni by a representative sample of soils from Galicia (N.W. Spain) was reproduced considerably more precisely by binary decision-tree regression models constructed using the CART algorithm than by linear regression models. Of the six metals competing for sorption sites in these experiments, Pb, Cu and Cr were sorbed and retained to a greater extent than Cd, Ni and Zn. Non-linear tree regression models constructed with CART fitted the data better than linear models, especially for Cd, Ni and Zn: and with both kinds of model the data for Pb, Cu and Cr were fitted better than those for Cd, Ni and Zn (the difference being much more marked for linear models), suggesting that the influence of soil properties on the sorption and retention of the latter three metals was limited by the preferential binding of the former three. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Acid Soils, Adsorption, Cart, Cd, Classification, Competition, Competitive Sorption, Complex, Cu, Desorption, Elsevier, Heavy Metal, Heavy Metals, Humic Umbrisols, Iron-Oxide, Linear Regression, Manganese-Oxide, Metals, Modelling, Models, Organic-Matter, Pb, Regression Trees, Retention, Selectivity Sequences, Soil, Soil Characteristics, Soils, Sorption, Spain, Zinc

? Hong, S., Wen, C., He, J., Gan, F.X. and Ho, Y.S. (2009), Adsorption thermodynamics of Methylene Blue onto bentonite. Journal of Hazardous Materials, 167 (1-3), 630-633.

Full Text: 2009\J Haz Mat-Ho2009-1.pdf, 2009\J Haz Mat-Ho2009-2.pdf; 2009\J Haz Mat-Ho2009-3.pdf; 2009\J Haz Mat-Ho2009-4.pdf; 2009\J Haz Mat167, 630.pdf

Abstract: The effect of temperature on the equilibrium adsorption of Methylene Blue dye from aqueous solution using bentonite was investigated. The equilibrium adsorption data were analyzed using three widely applied isotherms: Langmuir, Freundlich, and Redlich-Peterson. A non-linear method was used for comparing the best fit of the isotherms. Best fit was found to be Redlich-Peterson isotherm. Thermodynamic parameters, such as ΔG°, ΔH°, and ΔS°, were calculated using adsorption equilibrium constant obtained from the Langmuir isotherm. Results suggested that the Methylene Blue adsorption on bentonite was a spontaneous and endothermic process. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorbed Solution Theory, Adsorption, Adsorption Equilibrium, Adsorption Thermodynamics, Aqueous Solution, Aqueous-Solution, Basic Dye, Bentonite, Copper, Data, Dye, Endothermic, Equilibrium, Freundlich, Isotherm, Isotherms, Kinetics, Langmuir, Langmuir Isotherm, Lead, Metal-Ions, Methylene Blue, Non-Linear Method, Redlich-Peterson, Removal, Rights, Solution, Sorption, Sorption Isotherm, Temperature, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Tree Fern, Trial-and-Error Method

? Das, S.K. and Guha, A.K. (2009), Biosorption of hexavalent chromium by Termitomyces clypeatus biomass: Kinetics and transmission electron microscopic study. Journal of Hazardous Materials, 167 (1-3), 685-691.

Full Text: 2009\J Haz Mat167, 685.pdf

Abstract: Biosorption of Cr⁺⁶ by Termitomyces clypeatus has been investigated involving kinetics, transmission electron microscopy (TEM) and Fourier transform infrared spectroscopic (FTIR) studies. Kinetics experiments reveal that the uptake of chromium by live cell involves initial rapid surface binding followed by relatively slow intracellular accumulation. Of the different chromate analogues tested, only sulfate ion reduces the uptake of chromium to the extent of similar to 30% indicating chromate ions accumulation into the cytoplasm using sulfate transport system. Metabolic inhibitors, e.g. N,N’-dicyclohexylcarbodiimide, 2,4-ditrophenol and sodium azide inhibit chromate accumulation by similar to 30% in live cell. This indicates that accumulation of chromium into the cytoplasm occurs through the active transport system. TEM-EDXA analysis reveals that the chromium localizes in the cell wall and also in the cytoplasm. Reduction of chromate ions takes place by chromate reductase activity of cell-free extracts of T. clypeatus. FTIR study indicates that chromate ions accumulate into the cytoplasm and then reduced to less toxic Cr⁺³ compounds. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Accumulation, Adsorption, Biomass, Biosorption, Cadmium Transport, Chromate, Chromium, Cobalt, Copper, Cr(VI), Elsevier, FTIR, Hexavalent Chromium, Intracellular Accumulation, Kinetics, Pseudomonas-Fluorescens, Reduction, Removal, Resistance Plasmid, Sodium, Sulfate, System, TEM, Termitomyces Clypeatus, Transmission Electron Microscopy (TEM), Transport, Waste-Water

? Turan, N.G. and Ergun, O.N. (2009), Removal of Cu(II) from leachate using natural zeolite as a landfill liner material. Journal of Hazardous Materials, 167 (1-3), 696-700.

Full Text: 2009\J Haz Mat167, 696.pdf

Abstract: All hazardous waste disposal facilities require composite liner systems to act as a barrier against migration of contaminated leachate into the subsurface environment. Removal of copper(II) from leachate was studied using natural zeolite. A serial of laboratory systems on bentonite added natural zeolite was conducted and copper flotation waste was used as hazardous waste. The adsorption capacities and sorption efficiencies were determined. The sorption efficiencies increased with increasing natural zeolite ratio. The pseudo-first-order, the pseudo-second-order, Elovich and the intra-particle diffusion kinetic models were used to describe the kinetic data to estimate the rate constants. The second-order model best described adsorption kinetic data. The results indicated that natural zeolite showed excellent adsorptive characteristics for the removal of copper(II) from leachate and could be used as very good liner materials due to its high uptake capacity and the abundance in availability. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Capacities, Adsorption Kinetic, Availability, Barrier, Basic Dye, Bentonite, Capacity, Characteristics, Compacted Clay, Competitive Adsorption, Composite, Copper, Copper Flotation Waste, Copper(II), Cu(II), Data, Diffusion, Disposal, Elovich, Environment, Facilities, Flotation, Fly-Ash, Hazardous Solid Waste, Hazardous Waste, Heavy Metals, Hydraulic Conductivity, Intra-Particle Diffusion, Intraparticle Diffusion, Kinetic, Kinetic Models, Kinetics, Kinetics, Landfill, Leachate, Liner Materials, Migration, Model, Models, Natural, Natural Zeolite, Pseudo First Order, Pseudo Second Order, Pseudo-First-Order, Pseudo-Second-Order, Rate Constants, Removal, Rights, Second Order, Second-Order, Second-Order Model, Sorption, Subsurface, Systems, Uptake, Vitrification, Waste, Waste Disposal, Zeolite

? Velásquez, L. and Dussan, J. (2009), Biosorption and bioaccumulation of heavy metals on dead and living biomass of Bacillus sphaericus. Journal of Hazardous Materials, 167 (1-3), 713-716.

Full Text: 2009\J Haz Mat167, 713.pdf

Abstract: The tolerance to As, Hg, Co, Fe and Cr was determined in different Colombian Bacillus sphaericus native strains, as well as the biosorption and bioaccumulation in living biomass. In addition, biosorption of Cr in dead cells was also determined. Living cells of the two most tolerant strains had the capacity to accumulate between 6 and 47% of Co, Hg, Fe and As. Living and dead cells of B. sphaericus OT4b31 showed a biosorption of 25 and 44.5% of Cr respectively, while B. sphaericus IV(4)10 showed a biosorption of 32 and 45%. These results are due to the absence of an active metabolism in dead cells and to the pH adjustment. S-layer proteins may possibly have the ability to entrap metallic ions, either on living or dead cells. This can be an interesting alternative for bioremediation processes of heavy metals. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Bacillus Sphaericus, Bacteria, Biomass, Bioremediation, Biosorption, Capacity, Elsevier, Heavy Metals, Lead(II), Living And Dead Cells, Metals, pH, S-Layer

? Qu, R.J., Sun, C.M., Ma, F., Zhang, Y., Ji, C.N., Xu, Q., Wang, C.H. and Chen, H. (2009), Removal and recovery of Hg(II) from aqueous solution using chitosan-coated cotton fibers. Journal of Hazardous Materials,