Personal Research Database

186 (1), 863-868.

Full Text: 2011\J Haz Mat186, 863.pdf

Abstract: Porous granular ceramic adsorbents containing dispersed aluminum and iron oxides were synthesized by impregnating with salt solutions followed by precipitation at 600 degrees C. In the present work detailed studies were carried out to investigate the effect of contact time, adsorbent dose, initial solution pH and co-existing anions. Characterization studies on the adsorbent by SEM, XRD, EDS, and BET analysis were carried out to clarify the adsorption mechanism. The adsorbents were sphere in shape, 2-3 mm in particle size, highly porous and showed specific surface area of 50.69 sq m/g. The fluoride adsorption capacity of prepared adsorbent was 1.79 mg/g, and the maximum fluoride removal was obtained at pH 6. Both the Langmuir and Freundlich isotherm models were found to represent the measured adsorption data well. The experimental data were well explained with pseudo-second-order kinetic model. Results from this study demonstrated potential utility of Al/Fe dispersed in porous granular ceramics that could be developed into a viable technology for fluoride removal from aqueous solution. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Activated Alumina, Adsorption, Adsorption Isotherms, Adsorption Kinetics, Characterization, Column, Earth, Equilibrium, Exchange, Fixed-Bed, Fluoride Removal, Freundlich, Freundlich Isotherm, Isotherm, Kinetic, Kinetic Model, Langmuir, Performance, pH, Porous Granular Ceramic, Sludge, Waste-Water

? Gupta, V.K., Gupta, B., Rastogi, A., Agarwal, S. and Nayak, A. (2011), A comparative investigation on adsorption performances of mesoporous activated carbon prepared from waste rubber tire and activated carbon for a hazardous azo dye-Acid Blue 113. Journal of Hazardous Materials, 186 (1), 891-901.

Full Text: 2011\J Haz Mat186, 891.pdf

Abstract: A mesoporous carbon developed from waste tire rubber, characterized by chemical analysis, FTIR, and SEM studies, was used as an adsorbent for the removal and recovery of a hazardous azo dye, Acid Blue 113. Surface area, porosity, and density were determined. The adsorption of the dye over the prepared adsorbent and a commercial activated carbon was achieved under different pH, adsorbate concentration, sieve size, adsorbent dosage, contact time and temperature conditions. Langmuir and Freundlich adsorption isotherm models were applied and thermodynamic parameters were calculated. Kinetic studies indicated that the adsorption process follow first order kinetics and particle diffusion mechanisms are operative. By percolating the dye solution through fixed-bed columns the bulk removal of the Acid Blue 113 was carried out and necessary parameters were determined to find out the percentage saturation of both the columns. Recovery of the dye was made by eluting 0.1 M NaOH through the column. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Acid Blue 113, Activated Carbon, Adsorbent, Adsorption, Adsorption Isotherm, Adsorption Kinetics, Analysis, Aqueous-Solutions, Basic Dye, Biomass Oedogonium sp, Bottom Ash, Brilliant Blue, Column, Desorption, Diffusion, First Order, Fixed Bed, FTIR, Isotherm, Isotherm Models, Kinetic, Kinetic Studies, Kinetics, Low-Cost Adsorbents, Mechanisms, pH, Pyrolysis, Recovery, Removal, Sorption, Surface Area, Thermodynamic Parameters, Waste Rubber Tire, Water

? Zhang, D., Zhang, C.L. and Zhou, P. (2011), Preparation of porous nano-calcium titanate microspheres and its adsorption behavior for heavy metal ion in water. Journal of Hazardous Materials, 186 (2-3), 971-977.

Full Text: 2011\J Haz Mat186, 971.pdf

Abstract: Using D311 resin as a template, porous nano-calcium titanate microspheres (PCTOM) were prepared by a citric acid complex sol-gel method and characterized by X-ray diffraction (XRD), SEM and FTIR. The method’s adsorption capabilities for heavy metal ions such as lead, cadmium and zinc were studied and adsorption and elution conditions were investigated. Moreover, taking the cadmium ion as an example, the thermodynamics and kinetics of the adsorption were studied. The results show that the microspheres were porous and were made of perovskite nano-calcium titanate. The lead, cadmium and zinc ions studied could be quantitatively retained at a pH value range of 5-8. The adsorption capacities of PCTOM for lead, cadmium and zinc were found to be 141.8 mg g(-1), 18.0 mg g(-1) and 24.4 mg g(-1) respectively. The adsorption behavior followed a Langmuir adsorption isotherm and a pseudo-second-order kinetic model, where adsorption was an endothermic and spontaneous physical process. The adsorbed metal ions could be completely eluated using 2 mol L^-1 HNO₃ with preconcentration factors over 100 for all studied heavy metal ions. The method has also been applied to the preconcentration and FAAS determination of trace lead, cadmium and zinc ion in water samples with satisfactory results. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Isotherm, Atomic-Absorption-Spectrometry, Barium-Strontium Titanate, Cadmium, Cadmium Ion, Environmental-Samples, Flame Atomic Absorption Spectrometric, FTIR, Heavy Metal Ion, Isotherm, Kinetic, Kinetic Model, Kinetics, Langmuir, Lead-Ion, Packed Micro-Column, pH, Porous Nano-Calcium Titanate Microspheres, Preconcentration, Resin, Silica-Gel, Simultaneous Online Preconcentration, Solid-Phase Extraction, Template Method, Thermodynamics, Trace-Metals

? Meski, S., Ziani, S., Khireddine, H., Boudboub, S. and Zaidi, S. (2011), Factorial design analysis for sorption of zinc on hydroxyapatite. Journal of Hazardous Materials, 186 (2-3), 1007-1017.

Full Text: 2011\J Haz Mat186, 1007.pdf

Abstract: A factorial design was employed to evaluate the quantitative removal of zinc from aqueous solutions on synthesized hydroxyapatite. The experimental factors and their respective levels studied were the initial zinc concentration in solution (35 < C-zn <= 85 mg/L), adsorbent dosage (4.5 <= C-susp <= 9.5 g/L). Ca/P molar ratio (1.667 <= Ca/P <= 2) and calcination temperature of hydroxyapatite (600 <= T-Cal <= 800 degrees C). The adsorption parameters were analysed statistically by means of variance analysis by using the STATISTICA software. The experimental results and statistical analysis show that increasing in the calcination temperature from 600 to 800 degrees C decrease the zinc adsorption whereas the increase of adsorbent dosage increases it. Based on the analysis of variance and the factorial design of experiments, adsorbent dosage has a positive effect on the removal of zinc, whereas zinc concentration. Ca/P molar ratio and calcination temperature have a negative effect on this process. The factorial results also demonstrate the existence of statistically significant binary interactions of the experimental factors. The experimental results were fitted to the Langmuir and Freundlich equations to find out adsorption capacities. In most cases, the results indicate that the sorption data fits well in the Freundlich isotherm model. The results of XRD analysis, pH(pzc) and pH(Final) values indicated that ion exchange and dissolution/precipitation mechanisms predominate for the sorption of zinc on our hydroxyapatite. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorbent, Adsorbent Dosage, Adsorption, Adsorption Behavior, Adsorption Capacities, Analysis, Aqueous Solutions, Aqueous-Solution, Biomimetic Apatite, Calcination, Calcination Temperature, Concentration, Data, Design, Experimental, Experiments, Factorial Design, Freundlich, Freundlich Isotherm, Freundlich Isotherm Model, Heavy-Metals, Hydroxyapatite, Ion Exchange, Ion-Exchange, Isotherm, Isotherm Model, Langmuir, Lead Ions, Mechanisms, Model, pH(Pzc), Precipitation, Removal, Rights, Single-Metal, Software, Solution, Solutions, Sorption, Statistical Analysis, Statistical Modeling, Surface, Temperature, Waste-Water, XRD, Zinc

? Dubey, S.S. and Rao, B.S. (2011), Removal of cerium ions from aqueous solution by hydrous ferric oxide - A radiotracer study. Journal of Hazardous Materials, 186 (2-3), 1028-1032.

Full Text: 2011\J Haz Mat186, 1028.pdf

Abstract: Radiotracer technique has been used to study the removal behavior of Ce (III) ions from aqueous solutions by synthesized and well characterized hydrous ferric oxide (HFO). Adsorptive concentration (10(-4)-10(-8) mol dm(-3)), pH (ca 4.0-10.0) and temperature (303-333 K) were examined for assessing optimal conditions for removal of these ions. The uptake of Ce (III) ions, which fitted well for Freundlich and D-R isotherms, increased with increase in the temperature and no significant desorption took place in the studied temperature range. The presence of some anions/cations affected the uptake of metal ion markedly. Irradiation of hydrous ferric oxide and tungsten oxide by using a 11.1 x 10(9) Bq (Ra-Be) neutron source having a neutron flux of 3.9 x 10(6) cm(-2) s(-1) with associated gamma-dose rate of 1.72 Gy/h did not influence the extent of adsorption of Ce (III) significantly. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Aqueous Solution, Aqueous Solutions, Assessing, Behavior, Ce(III), Cerium, Chemisorption, Concentration, D-R, Desorption, Efficient Removal, Electron-Microprobe, Equilibrium Studies, Ferric Oxide, Freundlich, Hg(II), Hydrous Ferric Oxide, Ions, Isotherms, Kinetic Studies, Lysosomes, Metal, Oxide, pH, Polyaniline, Radiotracer, Removal, Rights, Solution, Solutions, Source, Temperature, Tungsten, Uptake

? Kumar, E., Bhatnagar, A., Kumar, U. and Sillanpää, M. (2011), Defluoridation from aqueous solutions by nano-alumina: Characterization and sorption studies. Journal of Hazardous Materials, 186 (2-3), 1042-1049.

Full Text: 2011\J Haz Mat186, 1042.pdf

Abstract: The present study was conducted to evaluate the feasibility of nano-alumina (Al₂O₃) for fluoride adsorption from aqueous solutions. The nature and morphology of pure and fluoride-sorbed nano-alumina were characterized by SEM with EDX, XRD, and FTIR analysis. Batch adsorption studies were performed as a function of contact time, initial fluoride concentration, temperature, pH and influence of competing anions. Fluoride sorption kinetics was well fitted by pseudo-second-order model. The maximum sorption capacity of nano-alumina for fluoride removal was found to be 14.0 mg g^-1 at 25ºC. Maximum fluoride removal occurred at pH 6.15. The fluoride sorption has been well explained using Langmuir isotherm model. Fluoride sorption was mainly influenced by the presence of PO₄^3-, SO₄^2- and CO₃^2- ions. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Isotherms, Batch, Batch Adsorption, Characterization, Defluoridation, Drinking-Water, Equilibrium, Fixed-Bed, Fluoride, Fluoride Removal, Fluoride Removal, FTIR, Hydroxide, Isotherm, Kinetics, Langmuir, Langmuir Isotherm, Mechanism, Nano-Alumina, Nanoparticles, Oxide, Performance, pH, Sorption, Sorption Mechanism

? Sun, X., Huang, X., Liao, X.P. and Shi, B. (2011), Adsorptive removal of Cu(II) from aqueous solutions using collagen-tannin resin. Journal of Hazardous Materials, 186 (2-3), 1058-1063.

Full Text: 2011\J Haz Mat186, 1058.pdf

Abstract: The collagen-tannin resin (CTR), as a novel adsorbent, was prepared via a reaction of collagen with black wattle tannin and aldehyde, and its adsorption properties to Cu(II) were systematically investigated, including pH effect, adsorption equilibrium, adsorption kinetics, and column adsorption. The adsorption capacity of Cu(II) on CTR was pH-dependent, and it increased with the increase of solution pH. The adsorption isotherms were well described by Langmuir isotherm model with correlating constant (R-2) higher than 0.99. The adsorption capacity determined at 303 K was high up to 0.26 mmol/g, which was close to the value (0.266 mmol/g) estimated from Langmuir equation. The adsorption capacity was increased with the increase of temperature, and thermodynamic calculations suggested that the adsorption of Cu(II) on CTR is an endothermic process. The adsorption kinetics were well fitted by the pseudo-second-order rate model. Further column studies suggested that CTR was effective for the removal of Cu(II) from solutions, and more than 99% of Cu(II) was desorbed from column using 0.1 mol/L HNO₃ solution. The CTR column can be reused to adsorb Cu(II) without any loss of adsorption capacity. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Batch Adsorption, Collagen-Tannin Resin, Column Adsorption, Copper Biosorption, Cu(II), Equilibrium, Isotherm, Isotherms, Kinetics, Langmuir, Langmuir Isotherm, Lead(II) Ions, Metal-Ion, Natural-Water Samples, pH, Preconcentration, Recovery, Resin, Thermodynamic, Trace Amounts

? Wang, Q.H., Chang, X.J., Li, D.D., Hu, Z., Li, R.J. and He, Q. (2011), Adsorption of chromium(III), mercury(II) and lead(II) ions onto 4-aminoantipyrine immobilized bentonite. Journal of Hazardous Materials, 186 (2-3), 1076-1081.

Full Text: 2011\J Haz Mat186, 1076.pdf

Abstract: In this work, the immobilization of 4-aminoantipyrine onto bentonite was carried out and it was then used to investigate the adsorption behavior of Cr(III). Hg(II) and Pb(II) ions from aqueous solutions. The separation and preconcentration conditions of analytes were investigated, including effects of pH, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. Under optimum pH value (pH 4.0), the maximum static adsorption capacity of the sorbent was found to be 38.8, 52.9 and 55.5 mg g(-1) for Cr(III). Hg(II) and Pb(II), respectively. 2.0 mL of 2% thiourea in 1.0 M HCl solution effectively eluted the adsorbed metal ions. The detection limit (3 sigma) of this method defined by IUPAC was found to be 0.12, 0.09 and 0.23 ng mL(-1) for Cr(III), Hg(II) and Pb(II), respectively. The relative standard deviation (RSD) was lower 3.0% (n = 8). The developed method has been validated by analyzing certified reference materials and successfully applied to the determination of trace Cr(III), Hg(II) and Pb(II) in water samples with satisfactory results. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: 4-Aminoantipyrine, Adsorption, Adsorption Behavior, Adsorption Capacity, Aqueous Solutions, Behavior, Bentonite, Biosorption, Capacity, Chromium(III), Cr(III), Effects, Elements, Elution, Emission Spectrometry, Flow, Flow Rate, Heavy Metal Ions, Heavy-Metals, Hg(II), ICP-MS, Immobilization, Immobilized, Immobilized Bentonite, Inductively Coupled Plasma Atomic, Ions, Lead(II), Mercury(II), Metal, Metal Ions, Pb(II), Pb(II) Ions, pH, pH Value, Platinum, Preconcentration, Recovery, Reference, Rights, Separation, Solid-Phase Extraction, Solid-Phase Extraction, Solution, Solutions, Sorbent, Standard, Value, Volume, Water, Water Samples, Work

? Anandkumar, J. and Mandal, B. (2011), Adsorption of chromium(VI) and Rhodamine B by surface modified tannery waste: Kinetic, mechanistic and thermodynamic studies. Journal of Hazardous Materials, 186 (2-3), 1088-1096.

Full Text: 2011\J Haz Mat186, 1088.pdf

Abstract: In this study, various activation methods have been employed to examine the potential reuse of tannery residual biomass (TRB) obtained from vegetable tanning process for the removal of Cr(VI) and Rhodamine B (RB) from aqueous solution. The maximum BET surface area (10.42 m²/g), honey comb pore distribution and uptake of both Cr(VI) and RB were achieved when only 3-fold volume of HCl was used to activate the biomass. The pH and temperature experiment showed that they have considerable impact on the adsorption capacity of the used adsorbent. The presence of other ions (Na⁺, Ca²⁺ and NH₄⁺) significantly reduces the metal uptake but marginal enhancement in the dye removal was observed when Na⁺ and NH₄⁺. ions were present in the solution. The equilibrium data fitted satisfactorily with the Langmuir model and monolayer sorption capacity obtained as 177-217 and 213-250 mg/g for Cr(VI) and RB at 30-50ºC. respectively. The sorption kinetics was found to follow the pseudo-second-order kinetic model. The increase in adsorption capacity for both metal and dye with increase in temperature indicates that the uptake was endothermic in nature. The results indicate that the HCl modified TRB (A-TRB) could be employed as a low cost adsorbent for the removal of both Cr(VI) and RB from the aqueous solution including industrial wastewater. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorbents, Adsorption, Agricultural Waste, Aqueous-Solution, Cashew Testa, Chromium(VI), Cr(VI), Dye, Dye Removal, Equilibrium, Heavy-Metal, Hexavalent Chromium, Kinetic, Kinetic Model, Kinetics, Langmuir, pH, Rhodamine B, Rice Husk, Sorption, Tannery Biomass, Thermodynamic, Waste, Wastewater, Water

? Hou, M.F., Ma, C.X., Zhang, W.D., Tang, X.Y., Fan, Y.N. and Wan, H.F. (2011), Removal of rhodamine B using iron-pillared bentonite. Journal of Hazardous Materials, 186 (2-3), 1118-1123.

Full Text: 2011\J Haz Mat186, 1118.pdf

Abstract: The iron-pillared bentonite (Fe-Ben) was prepared by ion-exchange using the natural bentonite (GZ-Ben) from Gaozhou, China, at room temperature without calcination. Both Fe-Ben and GZ-Ben were characterized by X-ray diffraction, N-2 adsorption and Fourier transform infrared spectroscopy. The results show that the d(0 0 1) value and surface area of the bentonite material increased after iron pillaring. Fe-Ben adsorbed much more Rhodamine B (RhB) than GZ-Ben, which can be ascribed to the special surface properties and large surface area of Fe-Ben. The optimum pH value for the adsorption of RhB on Fe-Ben is 5.0. The adsorption of RhB onto Fe-Ben can be well described by the pseudo-second-order kinetic model and the intraparticle diffusion kinetic model. The adsorption isotherm of RhB onto Fe-Ben matches well with the Langmuir model. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Isotherm, Adsorption-Kinetics, Aqueous-Solutions, Basic Dye, Bentonite, Catalysts, Cations, Clay, Clay, Degradation, Ion Exchange, Iron Pillaring, Isotherm, Kinetic, Kinetic Model, Langmuir, Methylene-Blue, Montmorillonite, pH, Removal, Rhodamine B, Samples

? Quintelas, C., Figueiredo, H. and Tavares, T. (2011), The effect of clay treatment on remediation of diethylketone contaminated wastewater: Uptake, equilibrium and kinetic studies. Journal of Hazardous Materials, 186 (2-3), 1241-1248.

Full Text: 2011\J Haz Mat186, 1241.pdf

Abstract: The ability of four different clays to adsorb diethylketone was investigated in batch experiments aiming to treat wastewater with low solvent concentrations. The adsorption performance in terms of uptake followed the sequence: vermiculite > sepiolite = kaolinite = bentonite, for all the adsorbent doses tested (from 0.1 to 1.5g) in 150 mL of ketone solution (800 mg/L). The equilibrium data in the batch systems were described by Sips and Dubinin-Raduskevich isotherms. The best fits for bentonite and kaolinite clays were obtained with the Sips isotherm and for sepiolite and vermiculite the best fits were obtained with the Dubinin-Raduskevich model. Kinetic data were described by pseudo-first and pseudo-second order kinetics models. The best fit was obtained for the pseudo-first order model which assumed that the interaction rate was limited only by one process or mechanism on a single class of sorbing sites and that all sites were time dependent. The presence of functional groups on the clay surface that might have interacted with the solvent was confirmed by FTIR. XRD analysis was also performed. This study showed that the tested clays are very effective for the removal of diethylketone from industrial effluents. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption, Aqueous-Solutions, Bentonite, Biodegradation, Chromium, Clays, Dichloromethane, Equilibrium, FTIR, Isotherm, Isotherms, Kaolinite, Ketones, Kinetic, Kinetics, Removal, Sepiolite, Solvent, Trichloroethylene, Wastewater

? Piau, C. and Aspray, T.J. (2011), Effectiveness and longevity of a green/food waste derived compost packed column to reduce Cr(VI) contamination in groundwater. Journal of Hazardous Materials, 186 (2-3), 1249-1253.

Full Text: 2011\J Haz Mat186, 1249.pdf

Abstract: PAS100 accredited compost derived from green and food waste sources was used to remediate groundwater containing Cr(VI) at a historically contaminated site in Falkirk, Scotland, UK. The compost was mixed with gravel at a ratio of 1:1 (v/v) to provide a reactive bedding material in an upflow column. The Cr(VI) concentration in the groundwater (inlet) ranged from 0.5 to 7.8 mg L-1 during the 168 d trial period. After an acclimation period of 54 d, the flow rate was increased in the column from 5.8 to 8 mL min(-1) Cr(VI) in the outlet was less than 100 mu g L-1 up to 134 d, after which the concentration steadily increased till 168 d. Compost analysis following completion of the trial confirmed that Cr(VI) was captured within the column. Anaerobic microbial reduction of Cr(VI) to Cr(III) was thought to be a key mechanism responsible for the longevity of the system to remove Cr(VI) from the groundwater. Requiring no additional organic carbon or nitrogen during the trial period, this setup represents a cost-effective treatment approach for low flow-through systems. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Analysis, Approach, Biological Reduction, Bioremediation, Carbon, Chromate Reduction, Column, Compost, Concentration, Contaminated Groundwater, Contamination, Cost-Effective, Cr(III), Cr(VI), Dissimilatory Metal Reduction, Flow, Flow Rate, Food, Groundwater, Hexavalent Chromium, Hexavalent Chromium, L1, Mechanism, Microbial, Nitrogen, Organic, Organic Carbon, Packed Column, Reduction, Remediation, Removal, Rights, Site, Sources, Systems, Till, Treatment, Trial, UK, Waste, Water

? Liu, Y., Guo, Y.P., Zhu, Y.C., An, D.M., Gao, W., Wang, Z., Ma, Y.J. and Wang, Z.C. (2011), A sustainable route for the preparation of activated carbon and silica from rice husk ash. Journal of Hazardous Materials, 186 (2-3), 1314-1319.

Full Text: 2011\J Haz Mat186, 1314.pdf

Abstract: An environmentally friendly and economically effective process to produce silica and activated carbon form rice husk ask simultaneously has been developed in this study. An extraction yield of silica of 72-98% was obtained and the particle size was 40-50 nm. The microstructures of the as-obtained silica powders were characterized by X-ray diffraction (XRD) and infrared spectra (IR). The surface area, iodine number and capacitance value of activated carbon could achieve 570 m(2)/g, 1708 mg/g, 180 F/g, respectively. In the whole synthetic procedure, the wastewater and the carbon dioxide were collected and reutilized. The recovery rate of sodium carbonate was achieved 92.25%. The process is inexpensive, sustainable, environmentally friendly and suitable for large-scale production. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Capacitors, Carbon, Carbon Dioxide, Carbonate, Chemical Activation, Environment-Friendly, Environmentally Friendly, Extraction, Hull Ash, IR, K2CO3, Malachite Green, Particle Size, Porous Carbon, Preparation, Procedure, Recovery, Rice, Rice Husk, Rice Husk Ash, Rice-Husk, Rights, Route, Silica, Size, Sodium, Surface, Surface Area, Sustainable, Value, Wastewater, X-Ray, X-Ray Diffraction, XRD

? Chen, H., Zhao, J. and Dai, G. (2011), Silkworm exuviae-A new non-conventional and low-cost adsorbent for removal of methylene blue from aqueous solutions. Journal of Hazardous Materials, 186 (2-3), 1320-1327.

Full Text: 2011\J Haz Mat186, 1320.pdf

Abstract: In this paper, silkworm exuviae (SE) waste, an agricultural waste available in large quantity in China, was utilized as low-cost adsorbent to remove basic dye (methylene blue, MB) from aqueous solution by adsorption. Kinetic data and sorption equilibrium isotherms were carried out in batch process. The adsorption kinetic experiments revealed that MB adsorption onto SE for different initial dye concentrations all followed pseudo-second order kinetics and were mainly controlled by the film diffusion mechanism. Batch equilibrium results at different temperatures suggest that MB adsorption onto SE can be described perfectly with Freundlich isotherm model compared with Langmuir and D-R isotherm models, and the characteristic parameters for each adsorption isotherm were also determined. Thermodynamic parameters calculated show the adsorption process has been found to be endothermic in nature. The analysis for the values of the mean free energies of adsorption (Ea), the Gibbs free energy (AG) and the effect of ionic strength all demonstrate that the whole adsorption process is mainly dominated by ion-exchange mechanism, which has also been verified by variations in FT-IR spectra and pH value before and after adsorption and desorption studies. The results reveal that SE can be employed as a low-cost alternative to other adsorbents for MB adsorption. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Isotherm, Batch, Cationic Dye, Congo Red, Copper Ions, Desorption, Dye, Dye Removal, Equilibrium, Equilibrium Isotherms, Fly-Ash, Freundlich, Freundlich Isotherm, FT-IR, FTIR, Ion Exchange, Ion-Exchange, Isotherm, Isotherms, Kinetic, Kinetics, Langmuir, Leaf Powder, Methylene Blue, pH, Silkworm Exuviae, Sorption, Surface-Chemistry, Thermodynamic, Waste, Waste-Water, Wheat Shells

? Dong, Q.A., Liu, J.S., Song, L. and Shao, G.Q. (2011), Novel zwitterionic inorganic-organic hybrids: Synthesis of hybrid adsorbents and their applications for Cu²⁺ removal. Journal of Hazardous Materials,