Personal Research Database

Full Text: 2009\J Haz Mat167, 10.pdf

Abstract: Mercury (Hg) is one of the most toxic heavy metals commonly found in the global environment. Its toxicity is related to the capacity of its compounds to bioconcentrate in organisms and to biomagnifie through food chain. A wide range of adsorbents has been used for removing Hg(II) from contaminated water. Chitosan is obtained by alkaline deacetylation of chitin. The adsorption capacity of chitosan depends on the origin of the polysaccharide, and on the experimental conditions in the preparation, that determine the degree of deacetylation. A great number of chitosan derivatives have been obtained by crosslinking with glutaraldehyde or epichlorohydrin among others or by grafting new functional groups on the chitosan backbone with the aim of adsorbing Hg(II). The new functional groups are incorporated to change the pH range for Hg(II) sorption and/or to change the sorption sites in order to increase sorption selectivity. The chemical modification affords a wide range of derivatives with modified properties for specific applications. Hg(II) adsorption on chitosan or chitosan derivatives is now assumed to occur through several single or mixed interactions: chelation or coordination on amino groups in a pendant fashion or in combination with vicinal hydroxyl groups, electrostatic attraction in acidic media or ion exchange with protonated amino groups. This review reports the recent developments in the Hg(II) removal in waste water treatment, using chitosan and its derivatives in order to provide useful information about the different technologies. When possibly the adsorption capacity of chitosan and chitosan derivatives under different experimental conditions is reported to help to compare the efficacy of the Hg(II) removal process. A comparison with the adsorption capacity of other low-cost adsorbents is also tabled. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Adsorption Capacity, Aqueous-Solution, Capacity, Chemical-Modification, Chitin, Chitosan, Chitosan Derivatives, Coconut Coir Pith, Cross-Linked Chitosan, Crosslinking, Dithiocarbamate-Chitosan, Elsevier, Grafting, Groups, Heavy Metals, Heavy-Metal Ions, Hg(II), Industry Waste-Water, Ion Exchange, Low-Cost Adsorbents, Mercury, Mercury(II) Removal, Mercury Ions, Metals, pH, Removal, Review, Selective Adsorption, Sorption, Treatment, Waste Water, Waste Water Treatment, Water, Water Treatment

? Wang, S.W., Hu, J., Li, J.X. and Dong, Y.H. (2009), Influence of pH, soil humic/fulvic acid, ionic strength, foreign ions and addition sequences on adsorption of Pb(II) onto GMZ bentonite. Journal of Hazardous Materials, 167 (1-3), 44-51.

Full Text: 2009\J Haz Mat167, 44.pdf

Abstract: This work contributed to the adsorption of Pb(II) onto GMZ bentonite in the absence and presence of soil humic acid (HA)/fulvic acid (FA) using a batch technique. The influences of pH from 2 to 12, ionic strengths from 0.004 M to 0.05 M NaNO₃, soil HA/FA concentrations from 1.6 mg/L to 20 mg/L, foreign cations (Li⁺, Na⁺, K⁺), anions (Cl^-, NO₃^-), and addition sequences on the adsorption of Pb(II) onto GMZ bentonite were tested. The adsorption isotherms of Pb(II) were determined at pH 3.6±0.1 and simulated with the Langmuir, Freundlich, and D-R adsorption models, respectively. The results demonstrated that the adsorption of Pb(II) onto GMZ bentonite increased with increasing pH from 2 to 6. HA was shown to enhance Pb(II) adsorption at low pH, but to reduce Pb(II) adsorption at high pH, whereas FA was shown to decrease Pb(II) adsorption at pH from 2 to 11. The results also demonstrated that the adsorption was strongly dependent on ionic strength and slightly dependent on the concentration of HA/FA. The adsorption of Pb(II) onto GMZ bentonite was dependent on foreign ions in solution. The addition sequences of bentonite/Pb(II)/HA had no effect on the adsorption of Pb(II). (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Isotherms, Aqueous-Solution, Bentonite, Complexation, Desorption, Elsevier, FA, Foreign Ions, Freundlich, Fulvic Acid, Fulvic-Acid, Humic Acid, Humic-Acid, Isotherms, Models, MX-80 Bentonite, Na-Rectorite, Pb(II), pH, Sorption, Temperature, Thorium(IV)

? Huang, J.H., Huang, K.L. and Yan, C. (2009), Application of an easily water-compatible hypercrosslinked polymeric adsorbent for efficient removal of catechol and resorcinol in aqueous solution. Journal of Hazardous Materials, 167 (1-3), 69-74.

Full Text: 2009\J Haz Mat167, 69.pdf

Abstract: An easily water-compatible hypercrosslinked resin HJ-1 was developed for adsorbing catechol and resorcinol in aqueous solution in this study. Its adsorption performances for catechol and resorcinol were investigated in aqueous solution by using the commercial Amberlite XAD-4 as a reference. The adsorption dynamic curves were measured and the adsorption obeyed the pseudo-second-order rate equation of Boyer and Hsu. The adsorption isotherms were scaled and Freundlich isotherm model characterized the adsorption better. The adsorption thermodynamic parameters were calculated and the adsorption was an exothermic, favorable, and more ordered process. The fact that the adsorption capacity of catechol was larger than resorcinol and the adsorption enthalpy of catechol was more negative than resorcinol can be explained in terms of the solubility and the polarity of two adsorbates. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Adsorbent, Adsorption, Adsorption Behavior, Adsorption Capacity, Adsorption Enthalpy, Adsorption Isotherms, Amberlite Xad-4, Amide Group, Aqueous Solution, Capacity, Carbon, Catechol, Chromatography, Dynamic, Electrochemical Treatment, Enthalpy, Exothermic, Freundlich, Freundlich Isotherm, Freundlich Isotherm Model, Hypercrosslinked Polymeric Adsorbent, Isotherm, Isotherm Model, Isotherms, Model, Phenolic-Compounds, Polymeric, Polymeric Adsorbent, Polystyrene, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Rate, Reference, Removal, Resin, Resorcinol, Response-Surface Methodology, Rights, Solubility, Solution, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Waste-Water, XAD-4

? Zheng, H., Liu, D.H., Zheng, Y., Liang, S.P. and Liu, Z. (2009), Sorption isotherm and kinetic modeling of aniline on Cr-bentonite. Journal of Hazardous Materials, 167 (1-3), 141-147.

Full Text: 2009\J Haz Mat167, 141.pdf

Abstract: In this paper, the sorption characteristics of aniline on Cr-bentonite prepared using synthetic wastewater containing chromium was investigated in a batch system at 30C. The effects of relevant parameters, such as pH value of solution, adsorbent dosage and initial aniline concentration were examined. The experimental data were analyzed by the Langmuir and Freundlich, and Temkin models of sorption. The sorption isotherm data were fitted well to Langmuir isotherm and the monolayer sorption capacity was found to be 21.60 mg/g at 30C. Dubinin-Redushkevich (D-R) isotherm was applied to describe the nature of aniline uptake and it was found that it occurred chemically. The kinetic data obtained at different concentrations were analyzed using a pseudo first-order, pseudo second-order kinetic equation and intraparticle diffusion model. The experimental data fitted very well the pseudo second-order kinetic model. Intraparticle diffusion affects aniline uptake. The results indicate that there is significant potential for Cr-bentonite as an adsorbent material for aniline removal from aqueous solutions. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Adsorbent, Adsorbent Dosage, Adsorption, Ammonium Ion, Aniline, Aqueous Solutions, Aqueous-Solution, Batch, Batch System, Capacity, Characteristics, Chromium, Concentration, Cr-Bentonite, Data, Diffusion, Diffusion Model, Dye, Equilibrium, Experimental, First Order, Freundlich, Intraparticle Diffusion, Intraparticle Diffusion Model, Isotherm, Kinetic, Kinetic Equation, Kinetic Model, Kinetic Modeling, Kinetics, Langmuir, Langmuir Isotherm, Model, Modeling, Models, Monolayer, Ozonation, pH, pH Value, Potential, Pseudo First Order, Pseudo First-Order, Pseudo Second Order, Pseudo Second-Order, Pseudo-First-Order, Pseudo-Second-Order, Removal, Rights, Second Order, Second-Order, Solution, Solutions, Sorption, Sorption Capacity, Sorption Isotherm, Uptake, Value, Wastewater, Water

? Zabihi, M., Ahmadpour, A. and Asl, A.H. (2009), Removal of mercury from water by carbonaceous sorbents derived from walnut shell. Journal of Hazardous Materials, 167 (1-3), 230-236.

Full Text: 2009\J Haz Mat167, 230.pdf

Abstract: The adsorption ability of a powdered activated carbon (PAC) derived from walnut shell was investigated in an attempt to produce more economic and effective sorbent for the control of Hg(II) ion from industrial liquid streams. Carbonaceous sorbents derived from Iranian walnut shell (WS) were prepared by chemical activation method using ZnCl₂ as an activating reagent. To the best of our knowledge, this adsorbent was not used before for removing mercury from water. Adsorption of Hg(II) from aqueous solutions was carried out under different experimental conditions by varying treatment time, metal ion concentration, adsorbent amount, pH and solution temperature. It was determined that Hg(II) adsorption follows both Langmuir and Freundlich isotherms as well as pseudo-second-order kinetics. It was also shown that Hg(II) uptake decreases with increasing pH of the solution. The proper choice of preparation conditions resulted in a microporous activated carbon with 0.45 g/cm(3) density, 737 mg/g iodine number and 780 m²/g BET surface area. The monolayer sorption capacity of this optimum adsorbent was obtained as 151.5 mg/g. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Activation, Adsorbent, Adsorption, Adsorption, Aqueous Solutions, Aqueous-Solution, Bagasse Fly-Ash, Bet, Bet Surface Area, Biomass, Capacity, Carbon, Chemical, Chemical Activation, Choice, Concentration, Control, Economic, Experimental, Freundlich, Gas, Hg(II), Ions, Isotherms, Kinetic, Kinetics, Knowledge, Langmuir, Langmuir and Freundlich Isotherms, Lead, Liquid, Mercury, Metal, Monolayer, PAC, pH Powdered Activated Carbon, Preparation, Pseudo Second Order, Pseudo Second Order Kinetics, Pseudo-Second-Order, Pseudo-Second-Order Kinetics, Removal, Rights, Solution, Solutions, Sorbent, Sorbents, Sorption, Sorption Capacity, Streams, Sugar-Industry Waste, Surface, Surface Area, Temperature, Treatment, Uptake, Walnut Shell, Water, ZnCl₂

? Viswanathan, N., Sundaram, C.S. and Meenakshi, S. (2009), Development of multifunctional chitosan beads for fluoride removal. Journal of Hazardous Materials, 167 (1-3), 325-331.

Full Text: 2009\J Haz Mat167, 325.pdf

Abstract: Chitosan beads (CB) which have negligible defluoridation capacity (DC) have been chemically modified by introducing multifunctional groups, viz., NH₃⁺ and COOH groups by means of protonation and carboxylation in order to utilize both amine and hydroxyl groups for fluoride removal. The protonated cum carboxylated chitosan beads (PCCB) showed a maximum DC of 1800 mg F-/kg whereas raw chitosan beads displayed only 52 mg F^-/kg. Sorption process was found to be independent of pH and slightly influenced in the presence of other common anions. The fluoride sorption on modified forms was reasonably explained by Freundlich and Langmuir isotherms. The sorbents were characterised by FTIR and SEM with EDAX analysis. The sorption process follows pseudo-second-order and intraparticle diffusion kinetic models. The suitability of PCCB has been tested with field sample collected from a nearby fluoride endemic area. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption, Analysis, Anions, Aqueous-Solutions, Beads, Capacity, Carboxylation, Chitosan, Composite, DC, Defluoridation, Defluoridation, Diffusion, Drinking-Water, EDAX, Equilibrium, Field, Fluoride, Fluoride Removal, Forms, Freundlich, FTIR, Intraparticle Diffusion, Ion-Exchange-Resin, Isotherms, Kinetic, Kinetic Models, Langmuir, Langmuir Isotherms, Lead, Mechanisms, Models, Modified, Multifunctional, pH Pseudo Second Order, Pseudo-Second-Order, Removal, Rights, SEM, Sorbents, Sorption, Sorption Process

? Guan, Q.Y., Wu, D.Y., Lin, Y., Chen, X.C., Wang, X.Z., Li, C.J., He, S.B. and Kong, H.N. (2009), Application of zeolitic material synthesized from thermally treated sediment to the removal of trivalent chromium from wastewater. Journal of Hazardous Materials, 167 (1-3), 244-249.

Full Text: 2009\J Haz Mat167, 244.pdf

Abstract: Zeolitic materials were synthesized from thermally treated sediment by alkali treatment using different NaOH/sediment ratios. Characterization of the materials was done by XRD, FTIR, cation exchange capacity and specific surface area. Use of high NaOH/sediment ratio favored the formation of zeolite. The potential value of the zeolitic materials for the retention of trivalent chromium from water was examined. The maximum of Cr(III) sorption by the zeolitic materials, determined by a repeated batch equilibration method, ranged from 38.9 to 75.8 mg/g which was much greater than that of the thermally treated sediment (6.3 mg/g). No release of sorbed Cr(III) by 1.0 M MgCl₂ at pH 7 was observed but Cr(III) desorption by ionic electrolyte increased with decreasing pH. The zeolitic materials could completely remove Cr(III) from wastewater even in the presence of Na⁺ and Ca²⁺ with high concentrations with a dose above 2.5 g/L. The pH-dependent desorption behavior and the high selectivity of zeolitic material for Cr(III) were explained by sorption at surface hydroxyl sites and formation of surface precipitates. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Aqueous-Solution, Capacity, Cation Exchange, Chromium, Coal Fly-Ash, Cr(III), Cr(III) Sorption, Desorption, Elsevier, Equilibrium, FTIR, Heavy-Metals, Immobilization, pH, Removal, Sediment, Sorption, Surface Area, Treatment, Trivalent Chromium, Wastewater, Water, XRD, Zeolite, Zeolitic Material

? El-Hendawy, A.N.A. (2009), The role of surface chemistry and solution pH on the removal of Pb²⁺ and Cd²⁺ ions via effective adsorbents from low-cost biomass. Journal of Hazardous Materials, 167 (1-3), 260-267.

Full Text: 2009\J Haz Mat167, 260.pdf

Abstract: A deep understanding of adsorption of Pb²⁺ and Cd²⁺ ions from their aqueous solutions on activated carbons and their HNO₃-oxidized forms has been attempted. These activated carbons were obtained from date pits using different activation methods. Adsorption isotherms of Pb²⁺ and Cd²⁺ ions were determined from solutions at pH 3 and 5.9. The results revealed that all obtained isotherms exhibited the model fitting according to Langmuir equation. The oxidized samples prone, slightly, to the high affinity isotherm type. The results revealed also that the investigated carbons removed appreciable amounts of lead and cadmium ions which increased by increasing pH of solutions from 3 to 5.9. The adsorption capacity of the investigated carbons also increased by HNO₃ acid surface treatment. The results were discussed in light of a possible chemical modification by nitric acid resulting in the creation of a large number of surface functional oxygen species. This interpretation was confirmed by FrlR investigation. The solution-pH and the surface chemistry of the carbons were found to play a decisive role in the uptake of these heavy metal ions from aqueous solutions rather than the carbon texture characteristics. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Activation, Adsorption, Adsorption Capacity, Adsorption Isotherms, Adsorptive Properties, Aqueous, Aqueous-Solution, Biomass, Cadmium, Capacity, Carbon, Copper, Elsevier, FTIR, Granular Activated Carbon, Heavy Metal, Heavy Metals Removal, Isotherm, Isotherms, Langmuir Equation, Lead, Mercury(II), Metal, Metal Ions, Metal-Ions, Oxidation, Pb²⁺, pH, Removal, Solution pH, Solutions, Sorption, Species, Surface Modification, Treatment, Waste

? Karthikeyan, M., Satheeshkumar, K.K. and Elango, K.P. (2009), Removal of fluoride ions from aqueous solution by conducting polypyrrole. Journal of Hazardous Materials, 167 (1-3), 300-305.

Full Text: 2009\J Haz Mat167, 300.pdf

Abstract: Conducting polypyrrole was found to possess potential efficiency to remove fluoride ions from aqueous solutions. The amount of fluoride ions removed per unit mass of the adsorbent, at 30°C from 10 mg/L fluoride ion solution, was estimated to be 6.37 mg/g. Batch sorption studies have been carried out to determine the effect of initial concentration of the sorbate, agitation time, adsorbent dose, pH, co-ions and temperature on the removal of fluoride by polypyrrole. The sorptive removal was found to be strongly pH and temperature dependent. The experimental data fitted well to the Freundlich and Dubinin-Radushkevick (D-R) isotherms. Thermodynamic parameters such as H°, S° and AGO were calculated indicating that the adsorption process was spontaneous and exothermic. FT-IR spectral studies suggested that the mechanism of fluoride ions removal follow chemisorption. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption, Aqueous, Carbon, Chemical-Synthesis, Chemisorption, Chitosan, Defluoridation, Defluoridation, Elsevier, Equilibrium, Freundlich, FT-IR, FTIR, Isotherms, Mechanism, pH, Polymers, Polypyrrole, Removal, Solutions, Sorption, Temperature, Thermodynamic, Thermodynamic Parameters, Water

? Ivanova, E. and Koumanova, B. (2009), Adsorption of sulfur dioxide on natural clinoptilolite chemically modified with salt solutions. Journal of Hazardous Materials, 167 (1-3), 306-312.

Full Text: 2009\J Haz Mat167, 306.pdf

Abstract: Various ion exchange forms of preliminary partly decationised zeolite (hydrogen forms) were obtained by indirect modification with metal salt solutions, as well as by direct treatment of natural clinoptilolite taken from Bulgarian deposits. Direct modification leads to a higher extent of samples enrichment with corresponding ion. Independently of the conditions, the alkaline and alkaline earth metal ions (especially sodium and calcium) were inserted at a greater extent, while the transitional metals-at a comparatively lower extent. The cationic forms of clinoptilolite were used for adsorption and desorption experiments. The breakthrough adsorption curves and the concentration curves at temperature-programmed desorption were obtained and compared. The breakthrough and saturation times, the adsorption capacity, the distribution coefficient, the adsorbed SO₂, the portions desorbed as SO₂ and SO₃, respectively, as well as the not desorbed portion of SO₂, were determined using these curves. It was established that a definite quantity of undesorbed SO₂ has remained in the zeolite forms modified with transitional metal cations. This statement was proved not only by the comparison between the adsorbed and desorbed quantities, but also by three-cycle adsorption-desorption experiments for the Cu²⁺-form. The results demonstrate a decrease in the capacity for each following cycle in an extent similar to the undesorbed SO₂ quantity. It was not observed a visible difference in the values of the distribution coefficients for adsorption on identical cation forms, directly or indirectly obtained. However, the breakthrough time of the samples obtained by ion exchange of the hydrogen form was longer in all cases. Definite quantities of desorbed SO3 were registered for all forms, except for the natural clinoptilolite and the samples enriched with alkaline and alkaline earth metal cations. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Capacity, Aqueous-Solutions, Bigadic Clinoptilolite, Cadmium, Capacity, Cu²⁺, Desorption, Distribution Coefficient, Elsevier, Heavy-Metals, Hydrogen, Ion Exchange, Ion-Exchange Properties, Metal, Metal Ions, Modification, Modified Zeolites, Natural Clinoptilolite, Pb²⁺, Removal, SO₂, Sodium, Solutions, Sorption, Sulfur Dioxide, Treatment, Zeolite

? Viswanathan, N., Sundaram, C.S. and Meenakshi, S. (2009), Development of multifunctional chitosan beads for fluoride removal. Journal of Hazardous Materials, 167 (1-3), 325-331.

Full Text: 2009\J Haz Mat167, 325.pdf

Abstract: Chitosan beads (CB) which have negligible defluoridation capacity (DC) have been chemically modified by introducing multifunctional groups, viz., NH3+ and COOH groups by means of protonation and carboxylation in order to utilize both amine and hydroxyl groups for fluoride removal. The protonated cum carboxylated chitosan beads (PCCB) showed a maximum DC of 1800 mg F-/kg whereas raw chitosan beads displayed only 52 mg F-/kg. Sorption process was found to be independent of pH and slightly influenced in the presence of other common anions. The fluoride sorption on modified forms was reasonably explained by Freundlich and Langmuir isotherms. The sorbents were characterised by FTIR and SEM with EDAX analysis. The sorption process follows pseudo-second-order and intraparticle diffusion kinetic models. The suitability of PCCB has been tested with field sample collected from a nearby fluoride endemic area. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption, Aqueous-Solutions, Capacity, Chitosan, Chitosan Beads, Composite, Defluoridation, Defluoridation, Diffusion, Drinking-Water, Elsevier, Equilibrium, Freundlich, FTIR, Groups, Intraparticle Diffusion, Ion-Exchange-Resin, Isotherms, Kinetic, Kinetic Models, Langmuir, Langmuir Isotherms, Lead, Mechanisms, Models, pH, Pseudo Second Order, Pseudo-Second-Order, Removal, Sem, Sorption

? Elwakeel, K.Z. (2009), Removal of Reactive Black 5 from aqueous solutions using magnetic chitosan resins. Journal of Hazardous Materials, 167 (1-3), 383-392.

Full Text: 2009\J Haz Mat167, 383.pdf

Abstract: Chitosan was cross-linked using glutaraldehyde in the presence of magnetite. The resin obtained was chemically modified through the reaction with tetraethylenepentamine followed by glycidyl trimethylammonium, chloride, to produce chitosan/amino resin (R1) and chitosan bearing both amine and quaternary ammonium chloride moieties (R2), respectively. The uptake of Reactive Black 5 (RB5) from aqueous solutions using R1 and R2 resins was studied using batch and column methods. The resins showed high affinity for the adsorption of RB5 where an uptake value of 0.63 and 0.78 mmol/g was reported for resins R1 and R2, respectively at 25C. Both kinetics and thermodynamic parameters of the process were estimated. These data indicated an endothermic spontaneous adsorption process and kinetically followed the pseudo-second order model. Breakthrough and regeneration curves for the removal of RB5 were studied. The adsorbed dye was eluted from the investigated resins effectively. Published by Elsevier B.V.

Keywords: Adsorption, Ammonium, Aqueous Solutions, Batch, Chelating Resins, Chitosan, Chloride, Column, Copper(II), Cross-Linked, Data, Dye, Endothermic, Exchange Resins, Glutaraldehyde, Indigo Carmine Dye, Kinetics, Magnetic, Magnetite, Methods, Microbial Decolorization, Model, Modified, Pseudo Second Order, Pseudo-Second Order, Pseudo-Second Order Model, Pseudo-Second-Order, Quaternary Amine, Reactive Black 5, Regeneration, Removal, Resin, Resins, Separation, Solutions, Thermodynamic, Thermodynamic Parameters, Uptake, Uptake Behavior, Value, Waste-Water, Wastewaters

? Yu, Z.H., Qi, T., Qu, J.K., Wang, L.N. and Chu, J.L. (2009), Removal of Ca(II) and Mg(II) from potassium chromate solution on Amberlite IRC 748 synthetic resin by ion exchange. Journal of Hazardous Materials,