Personal Research Database

Full Text: 2006\J Haz Mat137, 638.pdf

Keywords: Adsorption Isotherm, Separatin Factor, Lagergren I Order Kinetics, Citation Accuracy

? Mohan, D. and Pittman, Jr., C.U. (2006), Activated carbons and low cost adsorbents for remediation of tri- and hexavalent chromium from water: A review. Journal of Hazardous Materials, 137 (2), 762-811.

Full Text: 2006\J Haz Mat137, 762.pdf

Abstract: Hexavalent chromium is a well-known highly toxic metal, considered a priority pollutant. Industrial sources of Cr(VI) include leather tanning, cooling tower blowdown, plating, electroplating, anodizing baths, rinse waters etc. The most common method applied for chromate control is reduction of Cr(VI) to its trivalent form in acid (pH ~2) and subsequent hydroxide precipitation of Cr(III) by increasing the pH to ~9-10 using lime. Existing overviews of chromium removal only cover selected technologies that have traditionally been used in chromium removal. Far less attention has been paid to adsorption. Herein, we provide the first review article that provides readers an overview of the sorption capacities of commercial developed carbons and other low cost sorbents for chromium remediation. After an overview of chromium contamination is provided, more than 250 papers on chromium remediation using adsorption are discussed to provide recent information about the most widely used adsorbents applied for chromium remediation. Efforts to establish the adsorption mechanisms of Cr(III) and Cr(VI) on various adsorbents are reviewed. Chromium’s impact environmental quality, sources of chromium pollution and toxicological/ health effects is also briefly introduced. Interpretations of the surface interactions are offered. Particular attention is paid to comparing the sorption efficiency and capacities of commercially available activated carbons to other low cost alternatives, including an extensive table.

Keywords: Adsorption, Chromium, Hexavalent Chromium Adsorption, Trivalent Chromium Adsorption, Chromium Removal, Chromium Adsorption, Adsorbents, Solid Waste Utilization, Activated Carbons, Low Cost Adsorbents

? Özer, A. and Pirinççi, H.B. (2006), The adsorption of Cd(II) ions on sulphuric acid-treated wheat bran. Journal of Hazardous Materials, 137 (2), 849-855.

Full Text: 2006\J Haz Mat137, 849.pdf

Abstract: The adsorption of Cd(II) ions which is one of the most important toxic metals by using sulphuric acid-treated wheat bran (STWB) was investigated. The effects of solution pH and temperature, contact time and initial Cd(II) concentration on the adsorption yield were studied. The equilibrium time for the adsorption process was determined as 4 h. The adsorbent used in this study gave the highest adsorption capacity at around pH 5.4. At this pH, adsorption capacity for an initial Cd(II) ions concentration of 100 mg/L was found to be 43.1 mg/g at 25 °C for contact time of 4 h. The equilibrium data were analysed using Langmuir and Freundlich isotherm models to calculate isotherm constants. The maximum adsorption capacity (q_max) which is a Langmuir constant decreased from 101.0 to 62.5 mg/g with increasing temperature from 25 to 70 °C. Langmuir isotherm data were evaluated to determine the thermodynamic parameters for the adsorption process. The enthalpy change (ΔH°) for the process was found to be exothermic. The free energy change (ΔG°) showed that the process was feasible. The kinetic results indicated that the adsorption process of Cd(II) ions by STWB followed first-order rate expression and adsorption rate constant was calculated as 0.0081 l/min at 25 °C. It was observed that the desorption yield of Cd(II) was highly pH dependent.

Keywords: Wheat Bran, Sulphuric Acid, Adsorption, Cd(II) Ions

? Gong, R.M., Jin, Y.B., Chen, F.Y., Chen, J. and Liu, Z.L. (2006), Enhanced malachite green removal from aqueous solution by citric acid modified rice straw. Journal of Hazardous Materials, 137 (2), 865-870.

Full Text: 2006\J Haz Mat137, 865.pdf

Abstract: In this paper, rice straw was thermochemically modified with citric acid (CA) as esterifying agent. Two introduced free carboxyl groups of esterified rice straw were further loaded with sodium ion to yield potentially biodegradable cationic sorbent. In order to investigate the effect of chemical modification on the cationic dye sorption of rice straw, the removal capacities of native and modified rice straw sorbing a cationic dye (malachite green) from aqueous solution were compared. The effects of various experimental parameters (e.g. initial pH, sorbent dose, dye concentration, contact time) were investigated. For modified rice straw (MRS), the malachite green (MG) removal percentage came up to the maximum value beyond pH 4. For the 250 mg, l of MG solution, the 1.5 g, l or up of MRS could almost completely remove the dye from aqueous solution. Under the condition of 2.0 g, l sorbent used, the percentage of MG sorbed on MRS kept above 93% over a range from 100 to 500 mg, l of MG concentration. The sorption isotherms fitted the Langmuir or Freundlich models. The sorption equilibriums were reached at about 10 h. The sorption processes followed the pseudo-first-order rate kinetics. After chemical modification, the intraparticle diffusion rate constant (kid) was obviously increased. The results in this study indicated that MRS was an excellent sorbent for removal of MG from aqueous solution.

Keywords: Aqueous Solution, Cationic Dye, Chemical, Chemical Modification, Citric Acid, Concentration, Diffusion, Dye, Experimental, Freundlich, Intraparticle Diffusion, Isotherms, Kinetics, Langmuir, Malachite Green, MG, Models, Modification, Modified, MR, pH, Pseudo First Order, Pseudo-First-Order, Rate Constant, Rate Kinetics, Removal, Rice, Rice Straw, Sodium, Solution, Sorbent, Sorbent Dose, Sorption, Sorption Isotherms, Straw, Value

? Malkoc, E. (2006), Ni(II) removal from aqueous solutions using cone biomass of Thuja orientalis. Journal of Hazardous Materials, 137 (2), 899-908.

Full Text: 2006\J Haz Mat137, 899.pdf

Abstract: The biomass of terrestrial-plant materials has high removal capacities for a number of heavy metal ions. The Ni(II) biosorption capacity of the cone biomass of Thuja orientalis was studied in the batch mode. The biosorption equilibrium level was determined as a function of contact time, pH, temperature, agitation speed at several initial metal ion and adsorbent concentrations. The removal of Ni(II) from aqueous solutions increased with adsorbent concentration, temperature and agitation speed of the solution were increased. The biosorption process was very fast; 90% of biosorption occurred within 3 min and equilibrium was reached at around 7 min. It is found that the biosorption of Ni(II) on the cone biomass was correlated well (R² > 0.99) with the Langmuir equation as compared to Freundlich, BET Temkin and D-R isotherm equation under the concentration range studied. According to Langmuir isoterm, the monolayer saturation capacity (Q_o) is 12.42 mg g^-1. The pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models were applied to test the experimental data for initial Ni(II) and cone biomass concentrations. The pseudo-second-order kinetic model provided the best correlation of the used experimental data compared to the pseudo-first-order and intraparticle diffusion kinetic models. The activation energy of biosorption (Ea) was determined as 36.85 kJ mol^-1 using the Arrhenius equation. This study indicated that the cone biomass of T orientalis can be used as an effective and environmentally friendly adsorbent for the treatment of Ni(II) containing aqueous solutions. (c) 2006 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Activation, Activation Energy, Adsorbent, Adsorption, Agitation, Aqueous Solutions, Batch, Batch Mode, BET, Biomass, Biosorption, Biosorption, Biosorption Equilibrium, Capacity, Concentration, Cone Biomass of Thuja Orientalis, Contact, Copper(II) Ions, Correlation, D-R Isotherm, Data, Diffusion, Energy, Environmentally Friendly, Equilibrium, Experimental, Fixed-Bed Column, Freundlich, Function, Heavy Metal, Heavy Metal Ions, Heavy-Metal Ions, Intraparticle, Intraparticle Diffusion, Ions, Isotherm, Kinetic, Kinetic Model, Kinetic Models, Kinetics, Langmuir, Langmuir Equation, Metal, Metal Ion, Metal Ions, Mode, Model, Models, Monolayer, Ni(II), Ni(II) Biosorption, Nickel, Nickel Removal, pH, Process, Pseudo First Order, Pseudo Second Order, Pseudo Second Order Kinetic, Pseudo-First-Order, Pseudo-Second-Order, Pseudo-Second-Order Kinetic Model, Removal, Rights, Saturation, Solution, Solutions, Speed, Temperature, Thermodynamic Parameters, Thuja, Thuja Orientalis, Time, Treatment, Waste-Water

? Acar, F.N. and Eren, Z. (2006), Removal of Cu(II) ions by activated poplar sawdust (Samsun Clone) from aqueous solutions. Journal of Hazardous Materials, 137 (2), 909-914.

Full Text: 2006\J Haz Mat137, 909.pdf

Abstract: In this work, adsorption of Cu(II) ions on sawdust (SD) and activated sawdust (ASD) has been studied by using batch adsorption techniques. The equilibrium adsorption level was determined to be a function of the pH, initial Cu(II) concentration, and adsorbent dosage. The equilibrium nature of Cu(II) adsorption has been described by the Freundlich and Langmuir isotherms. The experimental adsorption data were fitted to the Langmuir adsorption model both sawdust and activated sawdust. The equilibrium capacity of sawdust and activated sawdust were 5.432 and 13.495 mg copper per g adsorbent, respectively at room temperature and natural pH. The maximum adsorption capacity was obtained at the maximum zeta potential value that -74.5 mV (pH 5) for activated sawdust and at -48.4 mV (pH 4) for sawdust. It was observed that activated sawdust was a suitable adsorbent than sawdust for removal of Cu(II) from aqueous solutions. (c) 2006 Elsevier B.V. All rights reserved.

Keywords: Activated Sawdust, Adsorbent, Adsorbent Dosage, Adsorption, Adsorption Capacity, Adsorption Isotherm, Aqueous Solutions, Batch, Batch Adsorption, Capacity, Concentration, Copper, Copper(II), Cu(II), Cu(II) Ions, Data, Equilibrium, Experimental, Freundlich, Function, Ions, Isotherms, Langmuir, Langmuir Isotherms, Model, Natural, pH, Poplar Sawdust, Potential, Removal, Room Temperature, Sawdust, Solutions, Techniques, Temperature, Value, Work, Zeta Potential

? Agrawal, A. and Sahu, K.K. (2006), Kinetic and isotherm studies of cadmium adsorption on manganese nodule residue. Journal of Hazardous Materials, 137 (2), 915-924.

Full Text: 2006\J Haz Mat137, 915.pdf

Abstract: The adsorption equilibrium and kinetics studies of cadmium (Cd) ions from aqueous solutions on manganese nodule residue were carried out by considering the influence of various parameters, such as contact time, solution pH and initial metal concentration in solution, temperature and adsorbent quantity. The adsorption of Cd increased with an increase in the concentrations of this metal in solution. Presence of manganese and iron content in manganese nodule residue (MNR) played a significant role in Cd(II) ions removal. The linear forms of the Langmuir and Freundlich equations were utilized for experiments with metal concentrations of 200 mg/L for Cd(II) as functions of solution pH (2.0–6.0). First-order rate equation and pseudo second-order rate equations were applied to study adsorption kinetics. Mass transfer study was also done to know the reaction rate. Thermodynamic parameters, such as standard Gibb’s free energy (ΔG°), standard enthalpy (ΔH°) and standard entropy (ΔS°), were also evaluated by Van’t Hoff equation. Thus, adsorption of Cd on this adsorbent was found to be spontaneous and exothermic thermodynamically. The adsorption capacity for Cd was found to be 19.8 mg/g of MNR. Under the optimised conditions, cadmium level was brought down from 100 mg/L to Cd less than detection limits and from 200 to 2 mg/L. Thus, the wastewater after cadmium removal could be safely disposed off on to land or sewage. Finally, the metal loaded adsorbent was subjected to desorption using different mineral acids and leaching by using toxicity characteristic leaching procedure (TCLP), synthetic precipitation leaching procedure (SPLP) tests for its further treatment or its safe disposal.

Keywords: Adsorbent, Adsorption, Adsorption Capacity, Adsorption Equilibrium, Adsorption Kinetics, Aqueous Solutions, Cadmium, Capacity, Cd, Cd(II), Cd(II) Ions, Concentration, Desorption, Disposal, Energy, Enthalpy, Entropy, Equilibrium, Exothermic, Experiments, Freundlich, Freundlich Model, Functions, Iron, Isotherm, Kinetic, Kinetics, Langmuir, Langmuir Model, Leaching, Manganese, Manganese Nodule Residue, Mass Transfer, Metal, pH, Precipitation, Procedure, Pseudo Second Order, Pseudo Second-Order, Pseudo-Second-Order, Removal, Role, Second Order, Second-Order, Sewage, Solution, Solutions, Standard, TCLP, Temperature, Thermodynamic, Thermodynamic Parameters, Toxicity, Treatment, Wastewater

? Deepatana, A. and Valix, M. (2006), Recovery of nickel and cobalt from organic acid complexes: Adsorption mechanisms of metal-organic complexes onto aminophosphonate chelating resin. Journal of Hazardous Materials, 137 (2), 925-933.

Full Text: 2006\J Haz Mat137, 925.pdf

Abstract: This study examined the recovery of nickel and cobalt from organic acid complexes using a chelating aminophosphonate Purolite S950 resin. These metal complexes are generated by bioleaching nickel laterite ores, a commercial nickel and cobalt mineral oxide, with heterotrophic organism and their metabolites or organic acid products. Equilibrium adsorption tests were conducted as a function of Ni and Co concentrations (15-2000 mg/L), solution pH (0.01 and 0.1 M acids) and three metabolic complexing agents (citrate, malate and lactate). It was shown that the adsorption of the various Ni- and Co-complexes on Purolite were quite low, 16-18 and 5.4-9 mg/g of resin, respectively, in comparison to the smaller nickel ions and nickel sulfate. This was attributed to the bulky organic ligands which promoted crowding effect or steric hindrance. The adsorption of these complexes was further hampered by the strong affinity of the resin to H+ ions under acidic conditions. Mechanisms of adsorption, as inferred from the fitted empirical Langmuir and Freundlich models, were correlated to the proposed steric hindrance and competitive adsorption effects. Nickel and cobalt elution from the resin were found be effective and were independent of the type of metal complexes and metal concentrations. This study demonstrated the relative challenges involved in recovering nickel and cobalt from bioleaching solutions. (c) 2006 Elsevier B.V. All rights reserved.

Keywords: Acids, Adsorption, Bioleaching, Chelating Resins, Cobalt, Competitive Adsorption, Freundlich, Ion-Exchange, Langmuir, Laterite, Metal-Organic Complexes, Nickel, Resin, Separation, Sorption, Zinc

? Entezari, M.H. and Bastami, T.R. (2006), Sono-sorption as a new method for the removal of lead ion from aqueous solution. Journal of Hazardous Materials, 137 (2), 959-964.

Full Text: 2006\J Haz Mat137, 959.pdf

Abstract: Sorption of Pb(II) as a toxic heavy metal ion, onto styrene-divinylbenzene co-polymer resin in the presence of ultrasound (sono-sorption) and in its absence (classical method) is presented in this work. Batch experiments were conducted to study the effect of the main parameters such as the amount of sorbent, concentration of sorbate, contact time, intensity of ultrasound and temperature on this sorption process. The equilibrium between liquid and solid phase was described by Langmuir model better than the Freundlich model. The time to reach equilibrium especially in the presence of ultrasound was very fast. This indicates that the resin mentioned has a high potential for the sorption of this pollutant ion. The isotherm constants were obtained under several different conditions. These constants were used in the calculation of the thermodynamic parameters of sorption. According to the results, the kinetics of sorption was in agreement with both pseudo-first-order and first-order reversible models. (c) 2006 Elsevier B.V. All rights reserved.

Keywords: Adsorbent, Adsorption, Aqueous Solution, Batch, Biosorbent, Cadmium, Capacity, Chromium, Copper, Equilibrium, Exchange, First Order, Freundlich, Freundlich Model, Heavy Metal, Isotherm, Kinetics, Langmuir, Langmuir Model, Lead, Lead Ion, Metal, Metal Ion, Metals, Model, Pb(II), Pseudo-First-Order, Removal, Resin, Sono-Sorption, Sorbate, Sorbent, Sorption, Thermodynamic, Thermodynamic Parameters, Ultrasound, Waste-Water

? Zhang, X., Li, A.M., Jiang, Z.M. and Zhang, Q.X. (2006), Adsorption of dyes and phenol from water on resin adsorbents: Effect of adsorbate size and pore size distribution. Journal of Hazardous Materials, 137 (2), 1115-1122.

Full Text: 2006\J Haz Mat137, 1115.pdf

Abstract: Batch adsorption runs of two commercial reactive dyes (methylene blue and reactive orange X-GN) and phenol from water onto two resin adsorbents (Amberlite XAD-4, a macroreticular adsorbent and ZCH-101, a hyper-cross-linked adsorbent) were carried out in the present study. Effect of adsorbate size and pore structure of the resin adsorbents on adsorption was discussed and Langmuir and Freundlich models were tested for the relevant adsorption isotherms. In the kinetic section concentration–time profiles were obtained to further elucidate the effect of adsorbate size and porous structure on adsorption mechanism. A pseudo-second-order model was proved to give a satisfactory description of the related kinetic results. Two-stage kinetic curve of methylene blue onto ZCH-101 was observed at a specific experimental condition and modeled schematically according to its specific pore size distribution. Furthermore, other kinetic experiments were performed at different ambient temperature to validate the proposed schematic model.

Keywords: Adsorbate Size, Adsorbent, Adsorbents, Adsorption, Adsorption Isotherms, Adsorption Mechanism, Amberlite XAD-4, Batch Adsorption, Distribution, Dyes, Experimental, Experiments, Freundlich, Isotherms, Kinetic, Kinetics, Langmuir, Mechanism, Methylene Blue, Model, Models, Phenol, Pore Size Distribution, Profiles, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Model, Reactive Dyes, Resin, Resin Adsorbent, Size, Structure, Temperature, Water, XAD-4

? Liu, Y., Shen, X., Xian, Q.M., Chen, H.D., Zou, H.X. and Gao, S.X. (2006), Adsorption of copper and lead in aqueous solution onto bentonite modified by 4’-methylbenzo-15-crown-5. Journal of Hazardous Materials, 137 (2), 1149-1155.

Full Text: 2006\J Haz Mat137, 1149.pdf

Abstract: The adsorption of heavy metal ions (Cu²⁺ and Pb²⁺) onto organobentonite modified by 4’-methylbenzo-15-crown-5 (MB15C5) from bentonite compared with natural bentonite (N-Bentonite) is described in this paper. The kinetic parameters of the models are calculated and discussed, and closely fitted a pseudo-second-order model in all cases. For bentonite modified with MB15C5 (MB15C5-Bentonite) and N-Bentonite, the equilibrium data closely fitted the Langmuir model and showed the following affinity order: Pb²⁺ > Cu²⁺, and the adsorption capacity of MB15C5-Bentonite is higher than that of N-Bentonite for Pb²⁺ and Cu²⁺. The effect of pH is examined over the range 1.5–6. The adsorption of Cu²⁺ and Pb²⁺ increases with increasing pH and the adsorption of Cu²⁺ and Pb²⁺ reaches a maximum at pH 3.5–6.

Keywords: 4’-Methylbenzo-15-Crown-5, Adsorption, Adsorption Capacity, Aqueous Solution, Bentonite, Capacity, Copper, Cu²⁺, Data, Equilibrium, Heavy Metal, Heavy Metal Ions, Kinetic, Kinetic Parameters, Langmuir, Langmuir Model, Lead, Metal, Metal Ions, Model, Models, Modified, Organobentonite, Pb²⁺, pH, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Model, Solution

? Kumar, Y.P., King, P. and Prasad, V.S.R.K. (2006), Equilibrium and kinetic studies for the biosorption system of copper(II) ion from aqueous solution using Tectona grandis L.f. leaves powder. Journal of Hazardous Materials, 137 (2), 1211-1217.

Full Text: 2006\J Haz Mat137, 1211.pdf

Abstract: The biosorption of copper(II) ions from aqueous solution by Tectona grandis L.f. was studied in a batch adsorption system as a function of pH, metal ion concentration, adsorbent concentration and adsorbent size. The biosorption capacities and rates of copper(II) ions onto T. grandis L.f. were evaluated. The Langmuir, Freundlich, Redlich–Peterson and Temkin adsorption models were applied to describe the isotherms and isotherm constants. Biosorption isothermal data could be well interpreted by the Langmuir model with maximum adsorption capacity of 15.43 mg/g of copper(II) ion on T. grandis L.f. leaves powder. The kinetic experimental data properly correlated with the second-order kinetic model. Various thermodynamic parameters such as ΔG°, ΔH°, and ΔS° were calculated indicating that this system was a spontaneous and exothermic process.

Keywords: Activated Carbon, Adsorbent, Adsorption, Adsorption Capacity, Adsorption Isotherm, Aqueous Solution, Batch, Batch Adsorption, Biomass, Biosorption, Biosorption Capacities, Biosorption Rates, Capacity, Chitosan Beads, Concentration, Copper(II), Data, Equilibrium, Exothermic, Experimental, Freundlich, Function, Heavy-Metals, Ions, Isotherm, Isothermal, Isotherms, Kinetic, Kinetic Model, Kinetic Studies, Langmuir, Langmuir Model, Lead(II), Metal, Metal Ion, Metal-Ions, Model, Models, pH, Process, Rates, Redlich-Peterson, Removal, Rhizopus-Arrhizus, Rights, Second Order, Second-Order, Single-Component, Size, Solution, Spontaneous, Tectona Grandis L.F, Thermodynamic, Thermodynamic Parameters

? Kumar, K.V. (2006), Comments on “Equilibrium studies for the adsorption of acid dye onto modified hectorite”. Journal of Hazardous Materials, 137 (2), 1252-1253.

Full Text: 2006\J Haz Mat137, 1252.pdf

Abstract: The present letter discusses the significance of the dimensionless separation factor of solid/liquid adsorption systems. The present letter also explain citing the original paper for using the term separation factor ‘R’.

Keywords: Adsorption, Citation Accuracy, Dye, Langmuir Isotherm, Modified, Paper, Separation, Separation Factor

? Dali-Youcef, N., Ouddane, B. and Derriche, Z. (2006), Adsorption of zinc on natural sediment of Tafna River (Algeria). Journal of Hazardous Materials, 137 (3), 1263-1270.

Full Text: 2006\J Haz Mat137, 1263.pdf

Abstract: The environmental impact of metal additions to sediment depends on its sorption ability. The paper presents a study of zinc adsorption using the experiment data on natural sediment of Tafna River in northwest of Algeria. The effect of various operating variables, namely initial concentration, mass of sediment, and contact time, have been studied. The optimum contact time needed to reach equilibrium is of the order of 30 min and is independent of initial concentration and mass of zinc ions. The extent of adsorption increases with increase of concentration, and with decrease of adsorbent mass. The content of carbonate in sediment increases the adsorption indicating the active support material towards zinc ions.

A batch sorption model, which assumes the pseudo-second-order mechanism, is developed to predict the rate constant of the sorption, the equilibrium sorption capacity and the initial sorption rate with the effect of initial zinc ion concentration and sediment dose. Various thermodynamic parameters, such as ΔG°, ΔH° and ΔS°, have been calculated. The thermodynamics of zinc ion/sediment system indicates spontaneous, endothermic and randomness nature of the process.

Keywords: Adsorbent, Adsorption, Adsorption Mechanism, Batch, Capacity, Carbonate, Concentration, Data, Endothermic, Environmental, Environmental Impact, Equilibrium, Experiment, Impact, Mechanism, Metal, Model, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Sorption Kinetics, Randomness, Rate Constant, Sediment, Sorption, Sorption Capacity, Support, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Zinc

? Park, D., Yun, Y.S., Lee, D.S., Lim, S.R. and Park, J.M. (2006), Column study on Cr(VI)-reduction using the brown seaweed Ecklonia biomass. Journal of Hazardous Materials,