Personal Research Database

Full Text: 2009\J Env Man90, 1782.pdf

Abstract: For immobilization technologies to be successful, the use of readily available and cost advantageous amendment is important when the remediation targets vast amounts of contaminated soils. The objectives of this study were to investigate whether the byproduct-synthesized hydroxyapatite can be used as an immobilizing amendment for dissolved Pb from a shooting range soil, and to model the kinetic data collected from dissolution experiments. A soil-solution kinetic experiment was conducted under fixed pH conditions as a function of time. A Pb-contaminated soil was reacted with various hydroxyapatite amendments to determine the dissolution rate and mineral products of soil Pb. Three types of amendments used were pure hydroxyapatite (HA), and poorly crystalline hydroxyapatites synthesized from gypsum waste (CHA), and synthesized from incinerated poultry litter (PHA). The dissolved Pb concentration decreased with the addition of amendments at pH 3-7. Both CHA and PHA were more effective than HA for attenuating Pb dissolution at pH 6 and above. According to the thermodynamic calculation at pH 6, the dissolved Pb-concentration for CHA and PHA treatments was predicted to be 66% and 50% lower than that of HA treatment, respectively. A better Pb immobilization effect demonstrated by CHA and PHA resulted in their greater solubility at higher pH, which may promote the formation of chloropyromorphite precipitates. Dissolution kinetics of soil Pb was adequately explained by pseudo-first order and pseudo-second order equations in acid pH ranges. According to the ion exchange model, an adequate agreement between the experimental data and regression curves was shown in the initial 40 min of the reaction process, but the accuracy of model predictability decreased thereafter. According to kinetic models and dissolution phenomena, CHA and PHA amendments had better Pb sorption capacity with rapid kinetics than pure hydroxyapatite at weak acid to neutral pH. (C) 2008 Elsevier Ltd. All rights reserved.

Keywords: Adsorption, Adsorption, Aqueous-Solutions, Divalent Metal-Ions, Gypsum Waste, Heavy-Metal, Immobilization, Immobilization, Ion Exchange, Kinetics, Mechanisms, Mineral Adsorbent, Phosphate, Pseudo-Second Order Rate, Removal, Sorption

? Aravindhan, R., Rao, J.R. and Nair, B.U. (2009), Application of a chemically modified green macro alga as a biosorbent for phenol removal. Journal of Environmental Management, 90 (5), 1877-1883.

Full Text: 2009\J Env Man90, 1877.pdf

Abstract: Phenol and substituted phenols are toxic organic pollutants present in tannery waste streams. Environmental legislation defines the maximum discharge limit to be 5-50 ppm of total phenols in sewers. Thus the efforts to develop new efficient methods to remove phenolic compounds from wastewater are of primary concern. The present work aims at the use of a modified green macro alga (Caulerpa scalpelliformis) as a biosorbent for the removal of phenolic compounds from the post-tanning sectional stream. The effects of initial phenol concentration, contact time, temperature and initial pH of the solution on the biosorption potential of macro algal biomass have been investigated. Biosorption of phenol by modified green macro algae is best described by the Langmuir adsorption isotherm model. Biosorption kinetics of phenol onto modified green macro algal biomass were best described by a pseudo second order model. The maximum uptake capacity was found to be 20 mg of phenol per gram of green macro algae. A Boyd plot confirmed the external mass transfer as the slowest step involved in the biosorption process. The average effective diffusion coefficient was found to be 1.4410^-9 cm²/s. Thermodynamic studies confirmed the biosorption process to be exothermic. (C) 2008 Elsevier Ltd. All rights reserved.

Keywords: Activated Carbon, Adsorption, Aqueous-Solution, Bagasse Fly-Ash, Biosorption, Biosorption, Dye, Equilibrium, Equilibrium Isotherm, Green Macro Alga, Macro Algae, Phenol, Pseudomonas-Putida, Sorption, Thermodynamic Studies, Waste-Water

? Pokhrel, D. and Viraraghavan, T. (2009), Biological filtration for removal of arsenic from drinking water. Journal of Environmental Management, 90 (5), 1956-1961.

Full Text: 2009\J Env Man90, 1956.pdf

Abstract: The main objective of the study was to find a suitable iron to arsenic ratio in water to reduce arsenic to 5 mu g/L or lower through sand filtration. Experiments were conducted by varying the quantity of iron(II) while keeping the arsenic concentration at 100 mu g/L A mixture of iron (II) and arsenic at different ratios (10:1, 20:1. 30:1 and 40:1) was pumped to the sand filters in a down flow mode and effluent arsenic and iron were analyzed. It was found that a ratio of iron to arsenic of 40:1 was necessary to ensure an effluent arsenic concentration of 5 mu g/L or lower. Iron in the filtrate was found to be below 0.1 mg/L at all times. (C) 2009 Elsevier Ltd. All rights reserved.

Keywords: Arsenic, Arsenic Removal, As(III) Oxidation, Bacteria, Bangladesh, Contaminated Groundwaters, Drinking Water, Effluent, Exposure, Intellectual Function, Iron, Iron Removal, Iron Removal, Manganese, Precipitation, Removal, Sand, Slow Sand Filtration, Treatment Plant, Water

? Gupta, V.K. and Suhas. (2009), Application of low-cost adsorbents for dye removal - A review. Journal of Environmental Management, 90 (8), 2313-2342.

Full Text: 2009\J Env Man90, 2313.pdf

Abstract: Dyes are an important class of pollutants, and can even be identified by the human eye. Disposal of dyes in precious water resources must be avoided, however, and for that various treatment technologies are in use. Among various methods adsorption occupies a prominent place in dye removal. The growing demand for efficient and low-cost treatment methods and the importance of adsorption has given rise to low-cost alternative adsorbents (LCAs). This review highlights and provides an overview of these LCAs comprising natural, industrial as well as synthetic materials/wastes and their application for dyes removal. In addition, various other methods used for dye removal from water and wastewater are also complied in brief From a comprehensive literature review, it was found that some LCAs, in addition to having wide availability, have fast kinetics and appreciable adsorption capacities too. Advantages and disadvantages of adsorbents, favourable conditions for particular adsorbate-adsorbent systems, and adsorption capacities of various low-cost adsorbents and commercial activated carbons as available in the literature are presented. Conclusions have been drawn from the literature reviewed, and suggestions for future research are proposed. (C) 2008 Elsevier Ltd. All rights reserved.

Keywords: Activated Carbons, Adsorbents, Adsorption, Adsorption Capacities, Agricultural Solid-Waste, Alternative, Application, Availability, Cotton Bleaching Effluent, Cross-Linked Chitosan, Demand, Dye, Dye Removal, Dye Removal From Water, Dyes, Granular Activated Carbon, Human, Kinetics, Liquid-Phase Adsorption, Literature, Literature Review, Low Cost, Low Cost Adsorbents, Low-Cost Adsorbents, Metal Hydroxide Sludge, Methods, Methylene-Blue Removal, Natural, Non-Conventional Adsorbents, Pollutants, Reactive Azo Dyes, Removal, Research, Review, Rights, Surfactant-Modified Sepiolite, Systems, Technologies, Textile Waste-Water, Treatment, Wastewater, Wastewater Treatment, Water, Water Resources

? El Ashtoukhy, E.S.Z. (2009), Loofa egyptiaca as a novel adsorbent for removal of direct blue dye from aqueous solution. Journal of Environmental Management, 90 (8), 2755-2761.

Full Text: 2009\J Env Man90, 2755.pdf

Abstract: In this paper, Loofa egyptiaca (LE), an agricultural plant cultivated in Egypt, was used to prepare low-cost activated carbon (LEC1 and LEC2) adsorbents. The adsorbents (LE, LEC1 and LEC2) were evaluated for their ability to remove direct blue 106 dye from aqueous solutions. Batch mode experiments were conducted using various parameters such as pH, contact time, dye concentration and adsorbent concentration. The surface chemistry of LE, LEC1 and LEC2 was analyzed by scanning electron microscopy (SEM). The experimental data were examined using Langmuir, Freundlich, Temkin and Harkins-Jura isotherms. The results showed that the adsorption of direct blue 106 was maximal at the lowest value of pH (pH = 2). Removal efficiency was increased with an increase in dye concentration and a decrease in amount of adsorbent. Maximum adsorption capacity was found to be 57.14, 63.3 and 73.53 mg/g for LE, LEC1 and LEC2 respectively. Kinetics were also investigated using pseudo-first-order, pseudo-second-order and intra-particle diffusion models. The experimental data fitted very well with the pseudo-first-order and pseudo-second-order kinetic models. The results indicate that LE, LEC1, and LEC2 could be employed as adsorbents for the removal of direct blue dye from aqueous solutions. (C) 2009 Elsevier Ltd. All rights reserved.

Keywords: Acid, Activated Carbon, Activated Carbon, Adsorbent, Adsorbents, Adsorption, Adsorption Capacity, Adsorption Isotherm, Agricultural, Aqueous Solution, Aqueous Solutions, Basic-Dyes, Capacity, Carbon, Chemistry, Concentration, Data, Diffusion, Direct Blue Dye, Direct Dye, Dye, Efficiency, Egypt, Electron Microscopy, Equilibrium Isotherm, Experimental, Experiments, Fly-Ash, Freundlich, Intra-Particle Diffusion, Intraparticle Diffusion, Isotherms, Kinetic, Kinetic Models, Kinetics, Kinetics, Langmuir, Loofa, Low Cost, Methylene-Blue, Mode, Models, pH, Plant, Pseudo First Order, Pseudo Second Order, Pseudo-First-Order, Pseudo-Second-Order, Removal, Rice Husk Ash, Rights, Scanning Electron Microscopy, SEM, Solution, Solutions, Surface, Surface Chemistry, Value, Waste

? Gupta, S. and Babu, B.V. (2009), Utilization of waste product (tamarind seeds) for the removal of Cr(VI) from aqueous solutions: Equilibrium, kinetics, and regeneration studies. Journal of Environmental Management, 90 (10), 3013-3022.

Full Text: 2009\J Env Man90, 3013.pdf

Abstract: In the present study, an adsorbent was prepared from tamarind seeds and used after activation for the removal of Cr(VI) from aqueous solutions. The tamarind seeds were activated by treating them with concentrated sulfuric acid (98% w, w) at a temperature of 150°C. The adsorption of Cr(VI) was found to be maximum at low values of initial pH in the range of 1-3. The adsorption process of Cr(VI) was tested with Langmuir, Freundlich, Redlich-Peterson, Koble-Corrigan, Tempkin, Dubinin-Radushkevich and Generalized isotherm models. Application of the Langmuir isotherm to the system yielded a maximum adsorption capacity of 29.7 mg, g at an equilibrium pH value ranging from 1.12 to 1.46. The adsorption process followed second-order kinetics and the corresponding rate constants obtained were 2.605×10^-3, 0.818×10^-3, 0.557×10^-3 and 0.811×10^-3 g, mg min^-1 for 50, 200, 300 and 400 mg, L of initial Cr(VI) concentration, respectively. The regenerated activated tamarind seeds showed more than 95% Cr(VI) removal of that obtained using the fresh activated tamarind seeds. A feasible solution is proposed for the disposal of the contaminants (acid and base solutions) containing high concentrations of Cr(VI) obtained during the regeneration (desorption) process. (C) 2009 Elsevier Ltd. All rights reserved.

Keywords: Activated Carbon, Activation, Adsorbent, Adsorption, Adsorption, Adsorption Capacity, Aqueous Solutions, Batch Studies, Biosorption, Capacity, Chromium(VI), Coir Pith, Concentration, Contaminants, Cr(VI), Cr(VI) Removal, Desorption, Disposal, Equilibrium, Freundlich, Hexavalent Chromium, Isotherm, Isotherms, Kinetics, Langmuir, Langmuir Isotherm, Leaves, Low-Cost Adsorbents, Models, Moringa-Oleifera Seeds, pH, pH Value, Rate Constants, Redlich-Peterson, Regeneration, Removal, Rights, Second Order, Second Order Kinetics, Second-Order, Second-Order Kinetics, Solution, Solutions, Sorption, Tamarind Seeds, Temperature, Value, Waste, Water

? Boudrahem, F., Aissani-Benissad, F. and Aït-Amar, H. (2009), Batch sorption dynamics and equilibrium for the removal of lead ions from aqueous phase using activated carbon developed from coffee residue activated with zinc chloride. Journal of Environmental Management, 90 (10), 3031-3039.

Full Text: 2009\J Env Man90, 3031.pdf

Abstract: Lignocellulosic materials are good precursors for the production of activated carbon. In this work, coffee residue has been used as raw material in the preparation of powder activated carbon by the method of chemical activation with zinc chloride for the sorption of Pb(II) from dilute aqueous solutions. The influence of impregnation ratio (ZnCl₂/Coffee residue) on the physical and chemical properties of the prepared carbons was studied in order to optimize this parameter. The optimum experimental condition for preparing predominantly microporous activated carbons with high pore surface area (890 m²/g) and micropore volume (0.772 cm³/g) is an impregnation ratio of 100%. The developed activated carbon shows substantial capability to sorb Lead(II) ions from aqueous solutions and for relative impregnation ratios of 75 and 100%, the maximum uptake is practically the same. Thus, 75% represents the optimal impregnation ratio. Batch experiments were conducted to study the effects of the main parameters such as contact time, initial concentration of Pb(II), solution pH, ionic strength and temperature. The maximum uptake of Lead(II) at 25ºC was about 63 mg/g of adsorbent at pH 5.8, initial Pb(II) concentration of 10 mg/L, agitation speed of 200 rpm and ionic strength of 0.005 M. The kinetic data were fitted to the models of pseudo-first order and pseudo-second order, and follow closely the pseudo-second order model. Equilibrium sorption isotherms of Pb(II) were analyzed by the Langmuir, Freundlich and Temkin isotherm models. The Freundlich model gives a better fit than the others. Results from this study suggest that activated carbon produced from coffee residue is an effective adsorbent for the removal of lead from aqueous solutions and that ZnCl₂ is a suitable activating agent for the preparation of high-porosity carbons. (C) 2009 Elsevier Ltd. All rights reserved.

Keywords: Activated Carbon, Activated Carbons, Activation, Adsorbent, Adsorption, Agitation, Aqueous Phase, Aqueous Solutions, Cadmium, Carbon, Cd(II), Chemical, Chemical Activation, Chemical Activation, Chloride, Coffee Residue, Coir Pith, Concentration, Data, Dynamics, Equilibrium, Exothermic, Experimental, Experiments, Freundlich, Freundlich Isotherm, Freundlich Model, Impregnation, Ionic Strength, Ions, Isotherm, Isotherms, Kinetic, Langmuir, Lead, Lead(II), Model, Models, Pb(II), Pb(II) Ions, pH, Phosphoric-Acid Activation, Physical, Physical Activation, Preparation, Pseudo First Order, Pseudo Second Order, Pseudo-First Order, Pseudo-First Order and Pseudo-Second Order, Pseudo-First-Order, Pseudo-Second Order, Pseudo-Second Order Model, Pseudo-Second-Order, Removal, Rights, Solution, Solutions, Sorption, Sorption Isotherms, Strength, Surface, Surface Area, Surface-Chemistry, Temkin Isotherm, Temperature, Uptake, Volume, Waste, Work, Zinc, Zinc Chloride, ZnCl₂

? Xiao, F. and Huang, J.C.H. (2009), Comparison of biosorbents with inorganic sorbents for removing copper(II) from aqueous solutions. Journal of Environmental Management, 90 (10), 3105-3109.

Full Text: 2009\J Env Man90, 3105.pdf

Abstract: In comparison with several other reported inorganic sorbents, Camellia tree leaf and primary sludge obtained from a settling tank as a pretreatment to the activated sludge system in a Hong Kong sewage treatment plant were evaluated for removing Cu(II) from aqueous solutions. Experimental data were modeled by the Langmuir isotherm equation to estimate the maximum sorption capacity (q_max). Results show that, at pH 5.6, biosorbents, Camellia tree leaf and primary sludge in particular, exert higher sorption capacities (q_max > 40 mg g^-1) than inorganic sorbents, Na-montmorillonite (q_max = 33.3 mg g^-1), fly ash (q_max = 18.8 mg g^-1), and goethite powder (10.3 mg g^-1). Furthermore, a pseudo second-order kinetic model was found to properly describe the experimental data for both bio- and inorganic sorbents. Sorption of Cu(II) on the Camellia tree leaf and primary sludge were much faster than that on the inorganic sorbents. In addition, desorption tests revealed that the desorption capacities of the two biomaterials are higher than the other selected materials; and much more Cu(II) can be retrieved from the Cu(II)-loaded biosorbents. Finally, increasing solution pH was found to greatly increase q_max and accelerate sorption processes. (C) 2009 Elsevier Ltd. All rights reserved.

Keywords: Activated Sludge, Adsorbents, Adsorption, Aqueous Solutions, Biomaterials, Biosorbents, Capacity, Co-Removal, Comparison, Copper(II), Cu(II), Data, Desorption, Experimental, Fly Ash, Fly-Ash, Goethite, Heavy Metal, Heavy-Metals, Hong Kong, Isotherm, Kaolinite, Kinetic, Kinetic Model, Langmuir, Langmuir Isotherm, Low-Cost, Model, Montmorillonite, pH, Plant, Precipitation, Pretreatment, Primary, Pseudo Second Order, Pseudo Second-Order, Pseudo-Second-Order, Recovery, Rights, Second Order, Second-Order, Sewage, Sludge, Solution, Solutions, Sorbents, Sorption, Sorption Capacity, Sorption Isotherm, Sorption Kinetics, Treatment, Waste-Water

? Zhu, R.L., Zhu, J.X., Ge, F. and Yuan, P. (2009), Regeneration of spent organoclays after the sorption of organic pollutants: A review. Journal of Environmental Management, 90 (11), 3212-3216.

Full Text: 2009\J Env Man90, 3212.pdf

Abstract: Clay minerals modified with organic ions, also known as organoclays, have found applications in a wide range of organic pollution control fields because of their excellent sorption capacity towards organic pollutants. Regeneration of the spent organoclays after the sorption of organic pollutants is of great importance during their application in pollution control. In this review, the reported methods for the regeneration of the spent organoclays are summarized, including biological degradation, photo-assisted oxidation, chemical extraction/desorption, supercritical extraction, thermal desorption, et al. The characteristics and applications of these methods are briefly described. It shows that most of these methods have been developed for regenerating spent organoclays from wastewater treatment. The biological regeneration method, as an in situ, low cost and easy-operating method, is applicable for regenerating spent organoclays not only from wastewater treatment, but also from soil and groundwater remediation. (C) 2009 Elsevier Ltd. All rights reserved.

Keywords: Applications, Aqueous-Solutions, Capacity, Clay, Contaminated Soils, Control, Cost, Degradation, Desorption, Ethyl-Acetate, Extraction, Minerals, Modified Bentonite, Modified Clays, Modified Smectite, Organic Pollutants, Organoclays, Oxidation, Palladium Phthalocyaninesulfonate, Para-Nitrophenol, Pollutants, Pollution, Pollution Control, Pore Structure, Regeneration, Remediation, Review, Soil, Sorption, Sorption Capacity, Supercritical Carbon-Dioxide, Treatment, Wastewater, Wastewater Treatment

? Hasan, S.H. and Srivastava, P. (2009), Batch and continuous biosorption of Cu²⁺ by immobilized biomass of Arthrobacter sp. Journal of Environmental Management, 90 (11), 3313-3321.

Full Text: 2009\J Env Man90, 3313.pdf

Abstract: The ability of free and polysulphone immobilized biomass of Arthrobacter sp. to remove Cu²⁺ ions from aqueous solution was studied in batch and continuous systems. The Langmuir and Freundlich isotherm models were applied to the data. The Langmuir isotherm model was found to fit the sorption data indicating that sorption was monolayer and uptake capacity (Q₀) was 175.87 and 158.7 mg/g for free and immobilized biomass respectively at pH 5.0 and 30°C temperature, which was also confirmed by a high correlation coefficient, a low RMSE and a low Chi-square value. A kinetic study was carried out with pseudo-first-order reaction and pseudo-second-order reaction equations and it was found that the Cu²⁺ uptake process followed the pseudo-second-order rate expression. The diffusivity of Cu²⁺ on immobilized beads increased (0.402×10^-4 to 0.435×10^-4 cm²/s) with increasing concentration from 50 to 150 mg/L The maximum percentage Cu²⁺ removal (89.56%) and uptake (32.64 mg/g) were found at 3.5 mL/min and 20 cm bed height. In addition to this the Bed Depth Service Time (BDST) model was in good agreement with the experimental data with a high correlation coefficient (>0.995). Furthermore, sorption and desorption studies were also carried out which showed that polysulphone immobilized biomass could be reused for up to six sorption-desorption cycles. (C) 2009 Elsevier Ltd. All rights reserved.

Keywords: Adsorption, Aqueous Solution, Aqueous-Solution, Arthrobacter sp., Batch, BDST, Beads, Bed Depth Service Time (BDST) Model, Biomass, Biosorption, Capacity, Chi-Square, Chromium VI, Concentration, Copper, Correlation, Correlation Coefficient, Cu²⁺, Data, Desorption, Desorption Studies, Effluents, Experimental, Expression, Fixed-Bed Column, Freundlich, Freundlich Isotherm, Heavy-Metals, Immobilized, Immobilized Biomass, Ion Sorption, Ions, Isotherm, Isotherm Model, Kinetic, Kinetic Study, Kinetics, Langmuir, Langmuir Isotherm, Langmuir Isotherm Model, Low-Cost Adsorbents, Model, Models, Monolayer, pH, Pseudo First Order, Pseudo Second Order, Pseudo-First-Order, Pseudo-Second-Order, Pseudo-Second-Order Rate, Removal, Rights, Shrinking Core Model (SCM), Solution, Sorption, Sorption-Desorption, Systems, Temperature, Uptake, Value, Waste-Water

? Sousa, F.W., Sousa, M.J., Oliveira, I.R.N., Oliveira, A.G., Cavalcante, R.M., Fechine, P.B.A., Neto, V.O.S., de Keukeleire, D. and Nascimento, R.F. (2009), Evaluation of a low-cost adsorbent for removal of toxic metal ions from wastewater of an electroplating factory. Journal of Environmental Management, 90 (11), 3340-3344.

Full Text: 2009\J Env Man90, 3340.pdf

Abstract: In this study, sugar cane residue or bagasse was used for removal of toxic metal ions from wastewater of an electroplating factory located in northeast Brazil. Prior acid treatment increased the adsorption efficacies in batch wise experiments. The microstructure of the material before and after the treatment was investigated by X-ray diffraction, infrared spectroscopy and scanning electron microscopy. Column operations showed that removals of Cu²⁺, Ni²⁺ and Zn²⁺ from wastewater (in the absence of cyanide) were 95.5%, 96.3.0%, and 97.1%, respectively. Regeneration of the adsorbent obtained in acid indicated that the efficiencies decreased only after the fourth cycle of re-use. Acid-treated sugar cane bagasse can be considered a viable alternative to common methods to remove toxic metal ions from aqueous effluents of electroplating industries. (C) 2009 Elsevier Ltd. All rights reserved.

? Xiao, F. and Huang, J.C.H. (2010), Comparison of biosorbents with inorganic sorbents for removing copper(II) from aqueous solutions (vol 90, pg 3105, 2009). Journal of Environmental Management, 91 (3), 789.

Full Text: 2010\J Env Man91, 789.pdf

Keywords: Aqueous Solutions, Biosorbents, Copper(II), Solutions, Sorbents

? Jain, M., Garg, V.K. and Kadirvelu, K. (2010), Adsorption of hexavalent chromium from aqueous medium onto carbonaceous adsorbents prepared from waste biomass. Journal of Environmental Management, 91 (4), 949-957.

Full Text: 2010\J Env Man91, 949.pdf

Abstract: This paper reports the adsorption of Cr(VI) ions from aqueous solution by sulphuric acid treated sunflower waste. Two adsorbents, namely SHC and SSC, were prepared from sunflower plant head and stem waste. The adsorbents were characterized by FT-IR, SEM and EDX The surface areas of SHC and SSC were 1.17 and 1.28 m² g^-1, respectively. The effect of various process parameters namely pH, temperature, initial metal ion concentration, adsorbent dosage and contact time has been studied. The optimum conditions for removal of Cr(VI) were found to be pH = 2, contact time = 2 h, adsorbent dosage = 4.0 g/L, concentration = 250 mg/L, temperature = 25±1ºC, rpm = 180. The percent removal at these optimum conditions was found to be 75.7% and 85.4% for SHC and SSC respectively. The Freundlich, Langmuir and D-R models were applied for mathematical description of adsorption equilibrium. Adsorption data were well described by the Langmuir isotherm with maximum adsorption capacities of 53.76 mg/g and 56.49 mg/g for SHC and SSC, respectively. Overall, the experimental results suggest that SHC and SSC could be used as low cost alternative adsorbents for the treatment of Cr(VI) containing wastewater. A comparison of different kinetic models showed that our data fitted well to the pseudo-second order model. (C) 2009 Elsevier Ltd. All rights reserved.

Keywords: Activated Carbon, Adsorbent, Adsorbent Dosage, Adsorbents, Adsorption, Adsorption Capacities, Adsorption Equilibrium, Agricultural Waste, Alternative, Aqueous Medium, Aqueous Solution, Biomass, Biosorption, Chromium, Comparison, Concentration, Cost, Cr(VI), D-R Model, Data, EDX, Equilibrium, Experimental, Freundlich, FT-IR, FTIR, Hexavalent Chromium, Ions, Isotherm, Kinetic, Kinetic Models, Kinetics, Langmuir, Langmuir Isotherm, Low Cost, Metal, Metal Ion, Model, Models, pH, Plant, Products, Pseudo Second Order, Pseudo-Second Order, Pseudo-Second Order Model, Pseudo-Second-Order, Removal, Rights, Sawdust, SEM, Shell, Solution, Sulphuric Acid, Sunflower Biomass, Surface, Surface Areas, Temperature, Thermodynamic Parameters, Time, Treatment, VI, Waste, Waste Biomass, Wastewater, Water

? Ngah, W.S.W. and Fatinathan, S. (2010), Adsorption characterization of Pb(II) and Cu(II) ions onto chitosan-tripolyphosphate beads: Kinetic, equilibrium and thermodynamic studies. Journal of Environmental Management, 91 (4), 958-969.

Full Text: 2010\J Env Man91, 958.pdf

Abstract: Chitosan-tripolyphosphate (CTPP) beads were synthesized, characterized and were used for the adsorption of Pb(II) and Cu(II) ions from aqueous solution. The effects of initial pH, agitation period, adsorbent dosage, different initial concentrations of heavy metal ions and temperature were studied. The experimental data were correlated with the Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The maximum adsorption capacities of Pb(II) and Cu(II) ions in a single metal system based on the Langmuir isotherm model were 57.33 and 26.06 mg/g, respectively. However, the beads showed higher selectivity towards Cu(II) over Pb(II) ions in the binary metal system. Various thermodynamic parameters such as enthalpy (ΔHº), Gibbs free energy (ΔGº) and entropy (ΔSº) changes were computed and the results showed that the adsorption of both heavy metal ions onto CTPP beads was spontaneous and endothermic in nature. The kinetic data were evaluated based on the pseudo-first and -second order a kinetic and intraparticle diffusion models. Infrared spectra were used to elucidate the mechanism of Pb(II) and Cu(II) ions adsorption onto CTPP beads. (C) 2009 Elsevier Ltd. All rights reserved.

Keywords: Adsorbent, Adsorbent Dosage, Adsorption, Adsorption Capacities, Agitation, Aqueous Solution, Aqueous-Solutions, Beads, Binary Metal System, Changes, Characterization, Chitosan-Tripolyphosphate Beads, Copper(II) Ions, Cu(II), Cu(II) Ions, Data, Diffusion, Endothermic, Energy, Enthalpy, Entropy, Equilibrium, Experimental, Freundlich, Gel Beads, Gibbs Free Energy, Heavy Metal, Heavy Metal Ions, Heavy-Metal Ions, Hydrogel Beads, Intraparticle Diffusion, Ions, Isotherm, Isotherm Model, Kinetic, Langmuir, Langmuir Isotherm, Langmuir Isotherm Model, Mechanism, Mechanisms, Metal, Metal Ions, Model, Models, Parameters, Pb(II), Pb(II) Ions, pH, Pseudo-First and, Removal, Rights, Second Order, Selectivity, Solution, Sorption, Temperature, Thermodynamic, Thermodynamic Parameters, Thermodynamic Studies

? Ahmad, R. and Kumar, R. (2010), Adsorption studies of hazardous malachite green onto treated ginger waste. Journal of Environmental Management, 91 (4), 1032-1038.

Full Text: 2010\J Env Man91, 1032.pdf

Abstract: Adsorption of malachite green (MG) from aqueous solution onto treated ginger waste (TGW) was investigated by batch and column methods. The effect of various factors such as initial dye concentration, contact time, pH and temperature were studied. The maximum adsorption of MG was observed at pH 9. Langmuir and Freundlich isotherms were employed to describe the MG adsorption equilibrium. The monolayer adsorption capacities were found to be 84.03, 163.9 and 188.6 mg/g at 30, 40 and 50ºC, respectively. The values of thermodynamic parameters like ΔGº, ΔHº and ΔSº indicated that adsorption was spontaneous and endothermic in nature. The pseudo second order kinetic model fitted well in correlation to the experimental results. Rechienberg’s equation was employed to determine the mechanism of adsorption. The results indicated that film diffusion was a major mode of adsorption. The breakthrough capacities were also investigated. (C) 2009 Elsevier Ltd. All rights reserved.

Keywords: Acid Dyes, Activated Carbon, Adsorption, Adsorption Capacities, Adsorption Equilibrium, Aqueous Solution, Aqueous-Solutions, Basic Dye, Batch, Breakthrough, Breakthrough Capacity, Column, Concentration, Correlation, Diffusion, Dye, Dye Adsorption, Endothermic, Equilibrium, Experimental, Film Diffusion, Freundlich, Isotherms, Kinetic, Kinetic Model, Langmuir, Langmuir and Freundlich Isotherms, Malachite Green, Mechanism, Mechanism of Adsorption, Methods, Mg, Mode, Model, Monolayer, pH, Photo-Fenton Degradation, Pseudo Second Order, Pseudo-Second-Order, Removal, Rights, Second Order, Second-Order, Solution, Sorption, Surfactant-Modified Sepiolite, Temperature, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Time, Waste, Water

? Ofomaja, A.E. (2010), Equilibrium studies of copper ion adsorption onto palm kernel fibre. Journal of Environmental Management, 91 (7), 1491-1499.

Full Text: 2010\J Env Man91, 1491.pdf

Abstract: The equilibrium sorption of copper ions from aqueous solution using a new adsorbent, palm kernel fibre, has been studied. Palm kernel fibre is obtained in large amounts as a waste product of palm oil production. Batch equilibrium studies were carried out and system variables such as solution pH, sorbent dose, and sorption temperature were varied. The equilibrium sorption data was then analyzed using the Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin isotherms. The fit of these isotherm models to the equilibrium sorption data was determined, using the linear coefficient of determination, r(2), and the non-linear Chi-square, chi(2) error analysis. The results revealed that sorption was pH dependent and increased with increasing solution pH above the pH(PZC) of the palm kernel fibre with an optimum dose of 10 g/dm³. The equilibrium data were found to fit the Langmuir isotherm model best, with a monolayer capacity of 3.17×10^-4 mol/g at 339 K. The sorption equilibrium constant, K-a, increased with increasing temperature, indicating that bond strength between sorbate and sorbent increased with temperature and sorption was endothermic. This was confirmed by the increase in the values of the Temkin isotherm constant, B-1, with increasing temperature. The Dubinin-Radushkevich (D-R) isotherm parameter, free energy, E, was in the range of 15.7-16.7 kJ/mol suggesting that the sorption mechanism was ion exchange. Desorption studies showed that a high percentage of the copper was desorbed from the adsorbent using acid solutions (HCl, HNO₃ and CH₃COOH) and the desorption percentage increased with acid concentration. The thermodynamics of the copper ions/palm kernel fibre system indicate that the process is spontaneous and endothermic. (C) 2010 Elsevier Ltd. All rights reserved.

Keywords: Adsorbent, Adsorbents, Adsorption, Analysis, Aqueous Solution, Aqueous-Solution, Biosorption, Cadmium, Capacity, Chi-Square, Concentration, Copper, Copper Ion, Copper Ions, Data, Desorption, Endothermic, Energy, Equilibrium, Equilibrium Sorption, Equilibrium Studies, Error, Error Analysis, Freundlich, Ion Exchange, Ion-Exchange, Ions, Isotherm, Isotherm Model, Isotherms, Kinetics, Langmuir, Langmuir Isotherm, Langmuir Isotherm Model, Mechanism, Metal-Ions, Model, Models, Monolayer, Palm Kernel Fibre, Parameters, pH, pH-Dependent, Removal, Rights, Solution, Solutions, Sorbate, Sorbent, Sorbent Dose, Sorption, Sorption Mechanism, Strength, Temkin Isotherm, Temperature, Thermodynamics, Waste, Waste-Water

? Aksu, Z. and Balibek, E. (2010), Effect of salinity on metal-complex dye biosorption by Rhizopus arrhizus. Journal of Environmental Management, 91 (7), 1546-1555.

Full Text: 2010\J Env Man91, 1546.pdf

Abstract: In this study the biosorption of Yellow RL, a metal-complex anionic dye, by dried Rhizopus arrhizus, a filamentous fungus, was investigated as a function of initial solution pH, initial dye concentration and initial salt (sodium chloride) concentration. The fungus exhibited the maximal dye uptake at pH 2 in the absence and in the presence of salt. Dye uptake increased with the dye concentration up to 1000 mgl^-1 and diminished considerably in the presence of increasing concentrations of salt up to 50 g l^-1. The fungus biosorbed 85.4 mg dye g^-1 dried biomass at 100 mg l^-1 initial dye concentration in the absence of salt. When 50 g l^-1 salt was added to the biosorption medium, this value dropped to 60.8 mg g^-1 resulting in 28.8% reduction in biosorption capacity. The Redlich-Peterson and Langmuir-Freundlich were the most suitable adsorption models for describing the biosorption equilibrium data of the dye both individually and in salt containing medium. The pseudo-second-order and saturation type kinetic models depicted the biosorption kinetics accurately for all cases studied. Equilibrium and kinetic constants varied with the level of salt were expressed as a function of salt concentration. (C) 2010 Elsevier Ltd. All rights reserved.

Keywords: Adsorption, Aqueous-Solutions, Biomass, Biosorption, Biosorption Kinetics, Capacity, Chloride, Chrysosporium, Concentration, Data, Decolorization, Dye, Dye Biosorption, Equilibrium, Function, Fungus, Kinetic, Kinetic Models, Kinetics, Langmuir-Freundlich, Metal Complex Dye, Metal-Complex Dye, Models, pH, Pseudo Second Order, Pseudo-Second-Order, Redlich-Peterson, Reduction, Removal, Rhizopus Arrhizus, Rights, Salinity, Salt, Salt Concentration, Saturation, Sawdust, Sodium, Sodium Chloride, Solution, Uptake, Value, Wastewaters, Yellow Rl

? Li, Q., Yue, Q.Y., Sun, H.J., Su, Y. and Gao, B.Y. (2010), A comparative study on the properties, mechanisms and process designs for the adsorption of non-ionic or anionic dyes onto cationic-polymer/bentonite. Journal of Environmental Management, 91 (7), 1601-1611.

Full Text: 2010\J Env Man91, 1601.pdf

Abstract: The adsorption properties and mechanisms of a cationic-polymer/bentonite complex (EPI-DMA/bentonite), prepared from polyepicholorohydrin-dimethylamine and bentonite, for non-ionic dyes (Disperse Blue SBL and Vat Scarlet R) and anionic dyes (Reactive Violet K-3R and Acid Dark Blue 2G) were investigated in this study. The solution pH, presence of salt and surfactant can significantly affect the dye removal efficiency. The equilibrium data were analyzed using the Langmuir and Freundlich models. The Langmuir model is the most suitable to describe non-ionic dye adsorption, but for anionic dyes the Freundlich model is best. The kinetic data for the adsorption of different dyes were analyzed using pseudo first- and second-order equations, and the experimental data conformed to the pseudo second-order kinetic model better. The possibility of intraparticle diffusion was also examined by using the intraparticle diffusion equation. The single-stage batch adsorber design for the adsorption of both types of dyes onto EPI-DMA/bentonite was studied based on the Langmuir isotherm model for non-ionic dyes and the Freundlich isotherm model for anionic dyes. The results showed that the required amount of EPI-DMA/bentonite for 95% dye removal in 5 L dye solution with a concentration of 50 mg/L is 378.0 g for DB SBL, 126.5 g for VS R. 9.7 g for RV K-3R and 15.5 g for ADB 2G. (C) 2010 Elsevier Ltd. All rights reserved.

Keywords: Activated Carbon, Adsorption, Adsorption Properties, Anionic Dyes, Aqueous-Solutions, Batch, Batch Adsorber Design, Bentonite, Cationic-Polymer, Bentonite, Comparative Study, Concentration, Data, Design, Diffusion, Disperse Dyes, Dye, Dye Adsorption, Dye Removal, Dyes, Efficiency, Equilibrium, Experimental, First, Freundlich, Freundlich Isotherm, Freundlich Isotherm Model, Freundlich Model, Humic-Acid, Intraparticle Diffusion, Ionic-Strength, Isotherm, Isotherm Model, Kinetic, Kinetic Data, Kinetic Model, Langmuir, Langmuir Isotherm, Langmuir Isotherm Model, Langmuir Model, Low-Cost Adsorbents, Mechanisms, Methyl-Violet, Model, Models, Non-Ionic Dyes, pH, Pseudo Second Order, Pseudo Second-Order, Pseudo-Second-Order, Reactive Dyes, Removal, Removal Efficiency, Rights, Salt, Second Order, Second-Order, Solution, Surfactant, Waste-Water

? Ofomaja, A.E., Naidoo, E.B. and Modise, S.J. (2010), Biosorption of copper(II) and Lead(II) onto potassium hydroxide treated pine cone powder. Journal of Environmental Management, 91 (8), 1674-1685.

Full Text: 2010\J Env Man91, 1674.pdf

Abstract: Pine cone powder surface was treated with potassium hydroxide and applied for copper(II) and Lead(II) removal from solution. Isotherm experiments and desorption tests were conducted and kinetic analysis was performed with increasing temperatures. As solution pH increased, the biosorption capacity and the change in hydrogen ion concentration in solution increased. The change in hydrogen ion concentration for Lead(II) biosorption was slightly higher than for copper(II) biosorption. The results revealed that ion-exchange is the main mechanism for biosorption for both metal ions. The pseudo-first order kinetic model was unable to describe the biosorption process throughout the effective biosorption period while the modified pseudo-first order kinetics gave a better fit but could not predict the experimentally observed equilibrium capacities. The pseudo-second order kinetics gave a better fit to the experimental data over the temperature range from 291 to 347 K and the equilibrium capacity increased from 15.73 to 19.22 mg g^-1 for copper(II) and from 23.74 to 26.27 for Lead(II). Activation energy was higher for Lead(II) (22.40 kJ mol^-1) than for copper(II) (20.36 kJ mol^-1). The free energy of activation was higher for Lead(II) than for copper(II) and the values of H* and S*. indicate that the contribution of reorientation to the activation stage is higher for Lead(II) than copper(II). This implies that Lead(II) biosorption is more spontaneous than copper(II) biosorption. Equilibrium studies showed that the Langmuir isotherm gave a better fit for the equilibrium data indicating monolayer coverage of the biosorbent surface. There was only a small interaction between metal ions when simultaneously biosorbed and cation competition was higher for the Cu-Pb system than for the Pb-Cu system. Desorption studies and the Dubinin-Radushkevich isotherm and energy parameter, E, also support the ion-exchange mechanism. (C) 2010 Elsevier Ltd. All rights reserved.

Keywords: Activation Energy, Adsorption, Aqueous-Solution, Biomass, Biosorption, Cadmium, Desorption, Equilibrium, Equilibrium pH, Fly-Ash, Ion-Exchange, Ions, Isotherm, Kinetic, Kinetics, KOH Treatment, Langmuir, Langmuir Isotherm, Pine Cone Powder, Pseudo-Second Order Model, Removal, Sorption, Thuja-Orientalis

? Calvete, T., Lima, E.C., Cardoso, N.F., Vaghetti, J.C.P., Dias, S.L.P. and Pavan, F.A. (2010), Application of carbon adsorbents prepared from Brazilian-pine fruit shell for the removal of reactive orange 16 from aqueous solution: Kinetic, equilibrium, and thermodynamic studies. Journal of Environmental Management, 91 (8), 1695-1706.

Full Text: 2010\J Env Man91, 1695.pdf

Abstract: Activated (AC-PW) and non-activated (C-PW) carbonaceous materials were prepared from the Brazilian-pine fruit shell (Araucaria angustifolia) and tested as adsorbents for the removal of reactive orange 16 dye (RO-16) from aqueous effluents. The effects of shaking time, adsorbent dosage and pH on the adsorption capacity were studied. RO-16 uptake was favorable at pH values ranging from 2.0 to 3.0 and from 2.0 to 7.0 for C-PW and AC-PW, respectively. The contact time required to obtain the equilibrium using C-PW and AC-PW as adsorbents was 5 and 4 h at 298 K. respectively. The fractionary-order kinetic model provided the best fit to experimental data compared with other models. Equilibrium data were better fit to the Sips isotherm model using C-PW and AC-PW as adsorbents. The enthalpy and entropy of adsorption of RO-16 were obtained from adsorption experiments ranging from 298 to 323 K. (C) 2010 Elsevier Ltd. All rights reserved.

Keywords: Activated Carbon, Activated Carbon, Adsorbent, Adsorbent Dosage, Adsorbents, Adsorption, Adsorption Capacity, Adsorption-Kinetics, Aqueous Solution, Araucaria-Angustifolia Wastes, Basic Dye Removal, Batch Conditions, Brazilian-Pine Fruit Shell, Capacity, Carbon, Carbonaceous Materials, Corynebacterium-Glutamicum, Data, Dye, Effluents, Enthalpy, Entropy, Equilibrium, Experimental, Experiments, Isotherm, Isotherm Model, Kinetic, Kinetic Model, Methylene-Blue Biosorption, Model, Models, Nonlinear Isotherms, Pecan Nutshell, pH, Reactive Orange 16, Removal, Rights, Solution, Statistical Design, Thermodynamic, Thermodynamic Studies, Uptake, Yellow Passion-Fruit

? Srinivasan, A. and Viraraghavan, T. (2010), Decolorization of dye wastewaters by biosorbents: A review. Journal of Environmental Management, 91 (10), 1915-1929.

Full Text: 2010\J Env Man91, 1915.pdf

Abstract: Dye wastewater is one of the most difficult to treat. There has been exhaustive research on biosorption of dye wastewater. It is evolving as an attractive option to supplement conventional treatment processes. This paper examines various biosorbents such as fungi, bacteria, algae, chitosan and peat, which are capable of decolorizing dye wastewaters; discusses various mechanism involved, the effects of various factors influencing dye wastewater decolorization and reviews pretreatment methods for increasing the biosorption capacity of the adsorbents. The paper examines the mismatch between strong scientific progress in the field of biosorption and lack of commercialization of research. (C) 2010 Elsevier Ltd. All rights reserved.

Keywords: Adsorbents, Algae, Bacteria, Biosorbents, Biosorption, Blue-R Decolorization, Capacity, Chitosan, Conventional, Decolorization, Dye, Dye Wastewater, Field, Fungi, Immobilized Phanerochaete-Chrysosporium, Kluyveromyces-Marxianus Imb3, Lignin-Modifying Enzymes, Linked Chitosan Beads, Low-Cost Adsorbents, Mechanism, Methods, Peat, Pretreatment, Progress, Reactive Azo Dyes, Research, Review, Reviews, Rights, Rotating Biological Contactor, Scientific Progress, Textile Waste-Water, Treatment, Wastewater, Wastewaters, White-Rot Fungi

? García-Rosales, G. and Colín-Cruz, A. (2010), Biosorption of lead by maize (Zea mays) stalk sponge. Journal of Environmental Management, 91 (11), 2079-2086.

Full Text: 2010\J Env Man91, 2079.pdf

Abstract: This study investigated the removal of Pb(II) from aqueous solutions by a maize (Zea mays) stalk sponge. Equilibrium and kinetic models for Pb(II) sorption were developed by considering the effect of the contact time and concentration at the optimum pH of 6±0.2. The Freundlich model was found to describe the sorption energetics of Pb(II) by Z. mays stalk sponge, and a maximum Pb(II) loading capacity of 80 mg g^-1 was determined. The kinetic parameters were obtained by fitting data from experiments measuring the effect of contact time on adsorption capacity into pseudo-first and second-order equations. The kinetics of Pb(II) sorption onto Z. mays biosorbent were well defined using linearity coefficients (R-2) by the pseudo-second-order equation (0.9998). The results obtained showed that Zea may stalk sponge was a useful biomaterial for Pb(II) sorption and that pH has an important effect on metal biosorption capacity. (C) 2010 Elsevier Ltd. All rights reserved.

Keywords: Adsorption, Adsorption Capacity, Aqueous Solutions, Aqueous-Solutions, Biomass, Biosorbent, Biosorption, Capacity, Cellulose, Concentration, Data, Equilibrium, Experiments, Freundlich, Freundlich Model, Heavy-Metals, Ions, Kinetic, Kinetic Models, Kinetic Parameters, Kinetics, Lead, Loading, Maize, Metal, Model, Models, NOV, Pb(II), pH, Pseudo Second Order, Pseudo-First and, Pseudo-Second-Order, Pseudo-Second-Order Equation, Removal, Rights, Second Order, Second-Order, Site Density, Solutions, Sorption, Surface Properties, Waste-Water, Zea Mays, Zero Charge

? Anirudhan, T.S. and Jalajamony, S. (2010), Cellulose-based anion exchanger with tertiary amine functionality for the extraction of arsenic(V) from aqueous media. Journal of Environmental Management, 91 (11), 2201-2207.

Full Text: 2010\J Env Man91, 2201.pdf

Abstract: A novel cellulose-based anion exchanger (Cell-AE) with tertiary amine functionality was synthesized by graft polymerization reaction of cellulose and glycidyl methacrylate using N,N’-methylene-bis-acrylamide as a crosslinker and benzoyl peroxide as an initiator, followed by dimethylamine (amination) and acid (HCl) treatment. The chemical modification was confirmed by infrared spectroscopy and CHN analysis. The anion exchanger was used in batch processes to study AS(V) adsorption in solutions. The operating variables studied were pH, contact time, initial As(V) concentration, sorbent mass, and ionic strength. The process was affected by solution pH with an optimum adsorption occurring at pH 6.0. Adsorption equilibrium was achieved within 1 h. Increasing ionic strength of solution negatively affected the arsenic uptake. The adsorption process performed more than 99.0% of As(V) removal from an initial concentration of 25.0 mg/L. The process of adsorption followed pseudo-second-order kinetics. The adsorption equilibrium isotherm data were analyzed using the Langmuir, Freundlich, Redlich-Peterson and Langmuir-Freundlich equations. The Langmuir-Freundlich isotherm described the adsorption data over the concentration range 25-400 mg/L the adsorption mechanism appears to be a ligand-exchange process. A simulated groundwater sample was treated with Cell-AE to demonstrate its efficiency in removing As(V). The adsorbed As(V) ions were desorbed effectively by a 0.1 M NaOH solution. (C) 2010 Elsevier Ltd. All rights reserved.

Keywords: Adsorption, Adsorption, Adsorption Equilibrium, Adsorption Mechanism, Amination, Analysis, Arsenate, Arsenic, Arsenic (V), Arsenic(V), As(V), As(V) Removal, Batch, Cellulose, Chemical, Chemical Modification, Concentration, Data, Desorption, Efficiency, Equilibrium, Equilibrium Isotherm, Extraction, Freundlich, Glycidyl Methacrylate, Graft, Graft Polymerization, Graft-Copolymers, Groundwater, Heavy, Infrared Spectroscopy, Ionic Strength, Ions, Isotherm, Kinetics, Langmuir, Langmuir-Freundlich, Langmuir-Freundlich Isotherm, Ligand Exchange, Mechanism, Media, Metal-Ions, Modification, Modified Cellulose, NaOH, NOV, pH, Polymerization, Pseudo Second Order, Pseudo Second Order Kinetics, Pseudo-Second-Order, Pseudo-Second-Order Kinetics, Redlich-Peterson, Removal, Rights, Solution, Solutions, Sorbent, Sorption, Spectroscopy, Strength, Treatment, Uptake, Water

? Tseng, R.L., Wu, K.T., Wu, F.C. and Juang, R.S. (2010), Kinetic studies on the adsorption of phenol, 4-chlorophenol, and 2,4-dichlorophenol from water using activated carbons. Journal of Environmental Management, 91 (11), 2208-2214.

Full Text: 2010\J Env Man91, 2208.pdf

Abstract: This study uses rate parameters in pseudo-first-order (PFO) and pseudo-second-order (PSO) equations (k(1) and k(2)q(e), respectively) to judge the extent for approaching equilibrium in an adsorption process. Out of fifty-six systems collected from the literature, the adsorption processes with a k(2)q(e) value between 0.1 and 0.8 min^-1 account for as much as 70% of the total. These are classified as fast processes. This work compares the validity of PFO and PSO equations for the adsorption of phenol, 4-chlorophenol (4-CP), and 2,4-dichlorophenol (2,4-DCP) on activated carbons prepared from pistachio shells at different NaOH/char ratios. The activated carbons, recognized as microporous materials, had a surface area ranging from 939 to 1936 m²/g. Findings show that the adsorption of phenol, 4-CP, and 2,4-DCP on activated carbons had a k(2)q(e) value of 0.15-0.58 min^-1, reflecting the fast process. Evaluating the operating time by rate parameters revealed that k²q_e was 1.6-1.8 times larger than k(1). These findings demonstrate the significance of using an appropriate kinetic equation for adsorption process design. (C) 2010 Elsevier Ltd. All rights reserved.

Keywords: 2,4-DCP, 2,4-Dichlorophenol, 4-Chlorophenol, Activated Carbons, Adsorption, Aqueous-Solutions, Design, Equilibrium, Fly-Ash, Kinetic, Kinetic Equation, Kinetic Studies, Kinetics, KOH, Literature, Microporous Materials, Nov, Phenol, Pistachio-Nut Shells, Plum Kernels, Pore Structure, Process Design, Pseudo First Order, Pseudo Second Order, Pseudo-First-Order, Pseudo-Second-Order, Pyrolysis Conditions, Removal, Rights, Significance, Sorption, Surface, Surface Area, Surface-Area, Systems, Validity, Value, Water, Work

? Chen, C.Y., Yang, C.Y. and Chen, A.H. (2011), Biosorption of Cu(II), Zn(II), Ni(II) and Pb(II) ions by cross-linked metal-imprinted chitosans with epichlorohydrin. Journal of Environmental Management, 92 (3), 796-802.

Full Text: 2011\J Env Man92, 796.pdf

Abstract: Cross-linked metal-imprinted chitosan microparticles were prepared from chitosan, using four metals (Cu(II), Zn(II), Ni(II), and Pb(II)) as templates, and epichlorohydrin as the cross-linker. The microparticles were characterized by Fourier transform infrared spectroscopy, solid state (13)C nuclear magnetic resonance spectroscopy, and energy-dispersive X-ray spectroscopy. They were used for comparative biosorption of Cu(ll). Zn(II), Ni(II) and Pb(II) ions in an aqueous solution. The results showed that the sorption capacities of Cu(II), Zn(II), Ni(II), and Pb(II) on the templated microparticles increased from 25 to 74%. 13 to 46%, 41 to 57%, and 12 to 43%, respectively, as compared to the microparticles without metal ion templates. The dynamic study showed that the sorption process followed the second-order kinetic equation. Three sorption models, Langmuir, Freundlich, and Dubinin-Radushkevich, were applied to the equilibrium isotherm data. The result showed that the Langmuir isotherm equation best fitted for monolayer sorption processes. Furthermore, the microparticles can be regenerated and reused for the metal removal. (c) 2010 Elsevier Ltd. All rights reserved.

Keywords: Adsorption Properties, Anion Sorption, Aqueous Solution, Aqueous-Solution, Biosorption, Carboxymethyl-Chitosan, Chitosan, Cross-Linked, Cross-Linked Metal-Complexed Chitosan, Cu(II), Equilibrium, Equilibrium Isotherm, Freundlich, Heavy-Metals, Ions, Isotherm, Kinetic, Kinetic Equation, Kinetics, Langmuir, Langmuir Isotherm, Lead, Metal, Metal Ion, Metal Removal, Metals, Ni(II), Pb(II), Pb(II) Ions, Removal, Resin, Sorption, Template Ions, Waste-Water, Zn(II)

? Cardoso, N.F., Lima, E.C., Pinto, I.S., Amavisca, C.V., Royer, B., Pinto, R.B., Alencar, W.S. and Pereira, S.F.P. (2011), Application of cupuassu shell as biosorbent for the removal of textile dyes from aqueous solution. Journal of Environmental Management, 92 (4), 1237-1247.

Full Text: 2011\J Env Man92, 1237.pdf

Abstract: The cupuassu shell (Theobroma grandiflorum) which is a food residue was used in its natural form as biosorbent for the removal of C.I. Reactive Red 194 and C.I. Direct Blue 53 dyes from aqueous solutions. This biosorbent was characterized by infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption/desorption curves. The effects of pH, biosorbent dosage and shaking time on biosorption capacities were studied. In acidic pH region (pH 2.0) the biosorption of the dyes were favorable. The contact time required to obtain the equilibrium was 8 and 18 h at 298 K, for Reactive Red 194 and Direct Blue 53, respectively. The Avrami fractionary-order kinetic model provided the best fit to experimental data compared with pseudo-first-order, pseudo-second-order and chemisorption kinetic adsorption models. The equilibrium data were fitted to Langmuir, Freundlich, Sips and Radke-Prausnitz isotherm models. For both dyes the equilibrium data were best fitted to the Sips isotherm model. (C) 2010 Elsevier Ltd. All rights reserved.

Keywords: Activated Carbon, Adsorption, Adsorption Kinetics, Biosorbent, Biosorption, Cupuassu Shell, Dyes, Equilibrium, Freundlich, Isotherm, Kinetic, Kinetic Model, Kinetic-Parameters, Langmuir, Low-Cost Adsorbents, Malachite Green, Methylene-Blue, Nonlinear Isotherm Fitting, pH, Pine-Fruit Shell, Reactive Dyes, Statistical Design, Textile Dyes, W-Rh

? Alexandre-Franco, M., Fernández-González, C., Alfaro-Domínguez, M. and Gómez-Serrano, V. (2011), Adsorption of cadmium on carbonaceous adsorbents developed from used tire rubber. Journal of Environmental Management, 92 (9), 2193-2200.

Full Text: 2011\J Env Man92, 2193.pdf

Abstract: Carbonaceous adsorbents (CAs) are developed from used tire rubber (UTR) and tested as adsorbents of Cd²⁺ in aqueous solution. In the preparation of the CAs, UTR was treated thermally at 400-900ºC for 2 h in N₂ and at 850 degrees C for 2 h in steam. Concentrated NaOH, HCl, H₂SO₄, HNO₃ and H₂O₂ solutions were also used. UTR and H900 (i.e. UTR pyrolyzed at 900 degrees C) were treated with O₃ at 25ºC for 1 h and with air at 250ºC for 1 and 24 h. CAs were characterized texturally by N₂ adsorption at -196ºC, mercury porosimetry, and density measurements. The surface groups were analyzed by FT-IR spectroscopy. Using the batch method, the adsorption process of Cd²⁺ was studied mainly from the kinetic standpoint at various pH values of the adsorptive solution. Significant porosity developments are achieved only when UTR is heat-treated, in particular in steam. However, the variety and concentration of surface groups are low in CAs. This is so even for CAs prepared using oxidizing agents as strong as O₃ and H₂O₂, which has been associated with a lack of available or accessible surface active sites for oxidation in UTR and H900, respectively. Thermal and thermal-chemical treatments are usually more effective than chemical treatments to increase the adsorption of Cd²⁺ in aqueous solution. The adsorption process of Cd²⁺ is first fast and then much slower. Adsorption-time data fit better to a pseudo-second order kinetic equation than to a pseudo-first order kinetic equation. The extent to which the adsorption process occurs is strongly dependent on the pH of the Cd²⁺ solution, being larger at pH 4.6 or 7.0 according to the adsorbent. (C) 2011 Elsevier Ltd. All rights reserved.

Keywords: Activation, Adsorption, Batch Method, Black, Carbonaceous Adsorbents, Cd²⁺ Adsorption, Mercury, pH, Preparation, Pseudo-First Order, Pseudo-First-Order, Pseudo-Second Order, Pseudo-Second-Order, Removal, Used Tire Rubber, Waste Tyre Rubber, Water

? Kamari, A., Pulford, I.D. and Hargreaves, J.S.J. (2011), Binding of heavy metal contaminants onto chitosans - An evaluation for remediation of metal contaminated soil and water. Journal of Environmental Management, 92 (10), 2675-2682.

Full Text: 2011\J Env Man92, 2675.pdf

Abstract: The binding efficiency of chitosan samples for Ag⁺, Cd²⁺, Cu²⁺, Pb²⁺ and Zn²⁺ has been evaluated in order to consider their application to remediate metal contaminated soil and water. The sorption behaviour of metal ions was assessed using a batch technique at different contact time and initial metal concentration with different background electrolytes. The kinetics followed a pseudo-second-order model, while the equilibrium data correlated well with the Freundlich and Langmuir isotherm models. For example, the maximum sorption capacity (Q) for chitosan was estimated as 1.93 mmol/g for Ag⁺, 1.61 mmol/g for Cu²⁺, 0.94 mmol/g for Zn²⁺, 0.72 mmol/g for Cd²⁺ and 0.64 mmol/g for Pb²⁺. Covalent interaction between metal ions and functional groups (amino and hydroxyl) of the chitosans was the main binding mechanism. Ion exchange is not an important process. Chitosan and cross-linked chitosans were able to bind metal ions in the presence of K⁺, Cl^- and NO₃⁺. The nature of Cl⁺ and NO₃^- ions did not affect Zn²⁺ binding by the chitosans. Even at 11x dilution, the chitosans were able to retain metal ions on their surfaces. (C) 2011 Elsevier Ltd. All rights reserved.

Keywords: Adsorption, Aqueous-Solutions, Batch Technique, Binding Efficiency, Biomass, Biosorption, Chemistry, Chitosan, Contaminated Soil, Contaminated Water, Cross-Linked Chitosans, Equilibrium, Freundlich, Ion Exchange, Ion-Exchange, Ions, Isotherm, Kinetics, Langmuir, Langmuir Isotherm, Low-Cost Adsorbent, Mechanism, Remediation, Removal, Soil, Sorption, Waste-Water, Water

? Fosso-Kankeu, E., Mulaba-Bafubiandi, A.F., Mamba, B.B. and Barnard, T.G. (2011), Prediction of metal-adsorption behaviour in the remediation of water contamination using indigenous microorganisms. Journal of Environmental Management, 92 (10), 2786-2793.

Full Text: 2011\J Env Man92, 2786.pdf

Abstract: In recent years, the adsorption of heavy metal cations onto bacterial surfaces has been studied extensively. This paper reports the findings of a study conducted on the heavy metal ions found in mine effluents from a mining plant where Co²⁺ and Ni²⁺ bearing minerals are processed. Heavy metal ions are reported to be occasionally present in these mine effluents, and the proposed microbial sorption technique offers an acceptable solution for the removal of these heavy metals. The sorption affinity of microorganisms for metal ions can be used to select a suitable microbial sorbent for any particular bioremediation process. Interactions of heavy metal ions (Co²⁺ and Ni²⁺) and light metal ions (Mg²⁺ and Ca²⁺) with indigenous microbial cells (Brevundimonas spp., Bacillaceae bacteria and Pseudomonas aeruginosa) were investigated using the Langmuir adsorption isotherm, pseudo second-order reaction kinetics model and a binary-metal system. Equilibrium constants and adsorption capacities derived from these models allowed delineation of the effect of binding affinity and metal concentration ratios on the overall adsorption behaviour of microbial sorbents, as well as prediction of performance in bioremediation systems. Although microbial sorbents used in this study preferentially bind to heavy metal ions, it was observed that higher concentrations (> 90 mg/l) of light metal ions in multi-metal solutions inhibit the adsorption of heavy metal ions to the bacterial cell wall. However, the microbial sorbents reduced Ni²⁺ levels in the mine-water used (93-100% Ni²⁺ removal) to below the maximum acceptable limit of 350 mu g/l, established by the South African Bureau of Standards. Competition among metal ions for binding sites on the biomaterial surface can occur during the bioremediation process, but microbial sorption affinity for heavy metal ions can enhance their remediation in dilute (<5 mg/l heavy metal) wastewaters. (C) 2011 Elsevier Ltd. All rights reserved.

Keywords: Adsorption, Adsorption Isotherm, Adsorption Kinetics, Bacteria, Binding Affinity, Biomass, Biosorbent Behaviour, Biosorption Equilibria, Cations, Cells, Contamination, Equilibrium, Heavy Metal, Heavy Metal Ions, Heavy Metals, Heavy-Metals, Isotherm, Kinetics, Langmuir, Langmuir Adsorption Isotherm, Light Metals, Mine Wastewater, Pb(II), Remediation, Removal, Saccharomyces-cerevisiae, Sorbent, Sorption, Water

? Ozdes, D., Duran, C. and Senturk, H.B. (2011), Adsorptive removal of Cd(II) and Pb(II) ions from aqueous solutions by using Turkish illitic clay. Journal of Environmental Management, 92 (12), 3082-3090.

Full Text: 2011\J Env Man92, 3082.pdf

Abstract: The ability of Turkish illitic clay (TIC) in removal of Cd(II) and Pb(II) ions from aqueous solutions has been examined in a batch adsorption process with respect to several experimental conditions including initial solution pH, contact time, initial metal ions concentration, temperature, ionic strength, and TIC concentration, etc. The characterization of TIC was performed by using FTIR, XRD and XRF techniques. The maximum uptake of Cd(II) (11.25 mg g^-1) and Pb(II) (238.98 mg g^-1) was observed when used 1.0 g L^-1 of TIC suspension, 50 mg L^-1 of initial Cd(II) and 250 mg L^-1 of initial Pb(II) concentration at initial pH 4.0 and contact time of 240 min at room temperature. The experimental data were analyzed by the Langmuir, Freundlich, Temkin and Dubinin Radushkevich (D-R) isotherm models. The monolayer adsorption capacity of TIC was found to be 13.09 mg g^-1 and 53.76 mg g^-1 for Cd(II) and Pb(II) ions, respectively. The kinetics of the adsorption was tested using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models. The results showed that the adsorption of Cd(II) and Pb(II) ions onto TIC proceeds according to the pseudo-second-order model. Thermodynamic parameters including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes indicated that the present adsorption process was feasible, spontaneous and endothermic in the temperature range of 5-40 degrees C. (C) 2011 Elsevier Ltd. All rights reserved.

Keywords: Adsorption, Biosorption, Cadmium, Cd(II), Copper(II), Dubinin-Radushkevich, Equilibrium, Freundlich, Ftir, Heavy-Metals, Illitic Clay Mineral, Isotherm, Kinetic, Kinetics, Langmuir, Lead, Minerals, Modified Kaolinite, Montmorillonite, pH, Retention, Sorption, Thermodynamic, Thermodynamic Parameters, Waste-Water

? Sdiri, A., Higashi, T., Jamoussi, F. and Bouaziz, S. (2012), Effects of impurities on the removal of heavy metals by natural limestones in aqueous systems. Journal of Environmental Management, 93 (1), 245-253.

Full Text: 2012\J Env Man93, 245.pdf

Abstract: Effects of impurities on the removal of heavy metals by natural limestones in aqueous solutions were studied by evaluating various factors including limestone concentration, pH, contact time and temperature. Solutions of Pb(II), Cd(II), Cu(II) and Zn(II), prepared from chloride reagents at a concentration of 10 mg/L, were studied in a batch method. Four natural limestone samples, collected from the Campanian-Maastrichtian limestone beds in Tunisia, were used as adsorbents. Sorption experiments indicated that high removal efficiencies could be achieved. Limestone samples containing impurities, such as silica, iron/aluminum oxides and different kinds of clay minerals, demonstrated enhanced sorption capacity, nearing 100% removal in some cases. Kinetic experiments showed that the sorption of metal ions occurred rapidly at a low coverage stage, and that solutions were nearly at equilibrium after 60 min. Data trends generally fit pseudo-second order kinetic, and intra-particle diffusion, models. The following conditions were found to promote optimum, or near-optimum, sorption of heavy metals: 1) contact time of more than 60 min, 2) pH = 5, 3) >3 g/L limestone concentration and 4) T = 35ºC. The results of this study suggest that the limestones from northern Tunisia, that contain higher amounts of silica and iron/aluminum oxides, are promising adsorbents for the effective removal of toxic heavy metals from wastewaters. (C) 2011 Elsevier Ltd. All rights reserved.

Keywords: Adsorbents, Adsorption, Cadmium, Calcite, Cd(II), Clay, Clay Minerals, Concentration, Cu(II), Dissolution Rates, Equilibrium, Heavy Metals, Ions, Kinetic, Limestone, Metal Ions, Metals, Pb(II), pH, Precipitation, Salaria-Basilisca, Silica, Solutions, Sorption, Sorption, Temperature, Wastewater Treatment, Water, Zn(II)