Personal Research Database

Full Text: 2008\J Haz Mat160, 301.pdf

Abstract: In this study, eucalyptus camaldulensis bark, a forest solid waste, is proposed as a novel material for the removal of mercury(II) from aqueous phase. The operating variables studied were sorbent dosage, ionic strength, stirring speed, temperature, solution pH, contact time, and initial metal concentration. Sorption experiments indicated that the sorption capacity was dependent on operating variables and the process was strongly pH-dependent. Kinetic measurements showed that the process was uniform and rapid. In order to investigate the mechanism of sorption, kinetic data were modeled using the pseudo-first-order and pseudo-second-order kinetic equations, and intraparticle diffusion model. Among the kinetic models studied, the pseudo-second-order equation was the best applicable model to describe the sorption process. Equilibrium isotherm data were analyzed using the Langmuir and the Freundlich isotherms. The Langmuir model yields a much better fit than the Freundlich model. Isotherms have also been used to obtain the thermodynamic parameters such as free energy, enthalpy, and entropy of sorption. The maximum sorption capacity was 33.11 mg g^-1 at 20C and the negative value of free energy change indicated the spontaneous nature of sorption. These results demonstrate that eucalyptus bark is very effective in the removal of Hg(II) from aqueous solutions.

Keywords: Activated Carbon, Adsorption, Aqueous Phase, Aqueous Solutions, Batch Study, Capacity, Concentration, Data, Diffusion, Diffusion Model, Energy, Enthalpy, Entropy, Equilibrium, Equilibrium Isotherm, Equilibrium Studies, Eucalyptus Bark, Experiments, Forest, Freundlich, Freundlich Model, Heavy-Metal Ions, Hg(II), Intraparticle Diffusion, Intraparticle Diffusion Model, Ionic Strength, Isotherm, Isotherms, Kinetic, Kinetic Equations, Kinetic Models, Langmuir, Langmuir Model, Mechanism, Media, Mercury, Mercury(II), Metal, Model, Models, pH, pH-Dependent, Pseudo First Order, Pseudo Second Order, Pseudo-First-Order, Pseudo-Second-Order, Pseudo-Second-Order Equation, Removal, Rights, Solid Waste, Solution, Solutions, Sorbent, Sorbent Dosage, Sorption, Sorption Capacity, Sorption Process, Spontaneous, Strength, Temperature, Thermodynamic, Thermodynamic Parameters, Value, Waste, Waste-Water

? Gürü, M., Venedik, D. and Murathan, A. (2008), Removal of trivalent chromium from water using low-cost natural diatomite. Journal of Hazardous Materials, 160 (2-3), 318-323.

Full Text: 2008\J Haz Mat160, 318.pdf

Abstract: Trivalent chromium was removed from the artificial wastewater using low-cost diatomite in batch and continuous systems. In batch system, four different sizes and five different amount of sorbent were used. The effect of the temperature on sorption was evaluated with using three different temperatures. As a result of the experiments, 85% of the trivalent chromium was removed from the wastewater in conditions of using 1.29 mm grain material at 30C temperature for 60 min in batch system but chromium removal was 82% at 30C temperature for 22 min and 97% from the wastewater at 30C temperature for 80 min in continuous system. Also, the equilibrium adsorption isotherms have been analyzed by Langmuir and Freundlich models. The Langmuir isotherms have the highest correlation coefficients. Langmuir adsorption isotherm constants corresponding to adsorption capacity, q(0), were found to be 28.1, 26.5 and 21.8 mg Cr³⁺/g diatomite at 15, 30 and 45C, respectively. Adsorption process was an exothermic process as a result of thermodynamic parameters calculations. The kinetic data of the sorption showed that the pseudo second-order equation was the more appropriate, which indicate that the intraparticle diffusion is the rate-limiting factor. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Carbons, Adsorption, Adsorption Capacity, Adsorption Isotherm, Adsorption Isotherms, Adsorption Process, Aqueous-Solutions, Batch, Batch System, Capacity, Chromium, Chromium Removal, Continuous System, Correlation, Data, Diatomite, Diffusion, Equilibrium, Equilibrium, Exothermic, Experiments, Freundlich, Hexavalent Chromium, Intraparticle Diffusion, Ions, Isotherm, Isotherms, Kinetic, Langmuir, Langmuir Adsorption Isotherm, Langmuir Isotherms, Low Cost, Mechanisms, Models, Natural, Pseudo Second Order, Pseudo Second-Order, Pseudo Second-Order Equation, Pseudo-Second-Order, Reduction, Removal, Rights, Second Order, Second-Order, Second-Order Equation, Sepiolite, Sorbent, Sorption, Systems, Temperature, Thermodynamic, Thermodynamic Parameters, Trivalent Chromium, Waste-Water, Wastewater, Water, Water Pollution

? Cestari, A.R., Vieira, E.F.S. and Mota, J.A. (2008), The removal of an anionic red dye from aqueous solutions using chitosan beads - The role of experimental factors on adsorption using a full factorial design. Journal of Hazardous Materials, 160 (2-3), 337-343.

Full Text: 2008\J Haz Mat160, 337.pdf

Abstract: A factorial design was employed to evaluate the quantitative removal of an anionic red dye from aqueous solutions on epichlorohydrin-cross-linked chitosan. The experimental factors and their respective levels studied were the initial dye concentration in solution (25 or 600 mg L^-1), the absence or the presence of the anionic surfactant sodium dodecylbenzenesulfonate (DBS) and the adsorption temperature (25 or 55C). The adsorption parameters were analyzed statistically using modeling polynomial equations. The results indicated that increasing the dye concentration from 25 to 600 mg L-1 increases the dye adsorption whereas the presence of DBS increases it. The principal effect of temperature did not show a high statistical significance. The factorial results also demonstrate the existence of statistically significant binary interactions of the experimental factors. The adsorption thermodynamic parameters, namely H, G and S, were determined for all the factorial design results. Exothermic and endothermic values were found in relation to the H. The positive S values indicate that entropy is a driving force for adsorption. The G values are significantly affected by an important synergistic effect of the factors and not by the temperature changes alone. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Chitosan, Dyes, Adsorption Thermodynamics, Factorial Designs, Indigo Carmine Dye, Waste-Water, Thermodynamic Parameters, Activated Bentonite, Thermochemical Data, Silica-Gel, Kinetics, Optimization, Equilibrium, Adsorbents

? Sarı, A. and Tüzen, M. (2008), Biosorption of total chromium from aqueous solution by red algae (Ceramium virgatum): Equilibrium, kinetic and thermodynamic studies. Journal of Hazardous Materials, 160 (2-3), 349-355.

Full Text: 2008\J Haz Mat160, 349.pdf

Abstract: This study focused on the biosorption of total chromium onto red algae (Ceramium virgatum) biomass from aqueous solution. Experimental parameters affecting biosorption process such as pH, contact time, biomass dosage and temperature were studied. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherms. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The biosorption capacity of C. virgatum biomass for total chromium was found to be 26.5 mg/g at pH 1.5 and 10 g/L biomass dosage, 90 min equilibrium time and 20C. From the D-R isotherm model, the mean free energy was calculated as 9.7 kJ/mol, indicating that the biosorption of total chromium was taken place by chemisorption. The calculated thermodynamic parameters (G, H and S) showed that the biosorption of total chromium onto C. virgatum biomass was feasiable, spontaneous and exothermic at 20-50C. Kinetic evaluation of experimental data showed that the biosorption processes of total chromium followed well pseudo-second-order kinetics. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Algae, Aqueous Solution, Biomass, Biosorption, Biosorption Isotherms, Brown Seaweed, Capacity, Ceramium Virgatum, Chemisorption, Chromium, D-R Isotherm, Data, Energy, Equilibrium, Equilibrium Time, Evaluation, Exothermic, Experimental, Freundlich, Freundlich Isotherm, Green-Algae, Heavy-Metals, Isotherm, Isotherm Model, Isotherms, Kinetic, Kinetics, Langmuir, Langmuir Model, Marine-Algae, Model, Models, pH, Pseudo Second Order, Pseudo Second Order Kinetics, Pseudo-Second-Order, Pseudo-Second-Order Kinetics, Removal, Rights, Sargassum sp, Solution, Spontaneous, Temperature, Thermodynamic, Thermodynamic Parameters, Thermodynamic Studies, Thermodynamics, Total Chromium, Ulva-Fasciata, Waste-Water

? Stasinakis, A.S., Elia, I., Petalas, A.V. and Halvadakis, C.P. (2008), Removal of total phenols from olive-mill wastewater using an agricultural by-product, olive pomace. Journal of Hazardous Materials, 160 (2-3), 408-413.

Full Text: 2008\J Haz Mat160, 408.pdf

Abstract: The purpose of this study was to investigate the sorption of total phenols, which are contained in olive-mill wastewater (OMWW), on solid by-products of olive pomace processing mills. Preliminary batch experiments were conducted using three different types of olive pomace, dried olive pomace (OP-1), dried and solvent extracted olive pomace (OP-2)and dried, solvent extracted and incompletely combusted olive pomace (OP-3). According to the results, OP-3 showed high performance for total phenols sorption and stability. For sorbent concentration of 10 g L^-1 and sorbate concentration of 50 mg L^-1, more than 40% of initial total phenols concentration was removed. Sorption kinetics was well described by the pseudo-second order rate model (R-2 > 0.99). Total phenols removal efficiency was improved by increasing sorbent concentration and solution’s pH or decreasing particle size of the sorbent material. The Langmuir and Freundlich isotherms sufficiently described OP-3 sorption capacity for the concentration range studied (50-500 mg L^-1). Fixed bed sorption experiments showed that lower flow rates and smaller particle size of sorbent resulted in longer column exhaustion time and higher initial removal efficiency. Experiments with thermally or chemically regenerated OP-3 showed that sorption capacity deteriorated after regeneration. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Agricultural, Agricultural By-Product, Anaerobic-Digestion, Aqueous-Solutions, Batch, Batch Experiments, Biological Treatment, Capacity, Chromium(VI), Clay, Column, Concentration, Efficiency, Exhaustion, Experiments, Flow, Freundlich, Isotherms, Kinetics, L1, Langmuir, Langmuir and Freundlich Isotherms, Model, Olive Pomace, Particle Size, Performance, pH, Phenolic Compounds, Phenols, Pseudo Second Order, Pseudo-Second Order, Pseudo-Second-Order, Purpose, Rates, Reagent, Regeneration, Removal, Removal Efficiency, Rights, Size, Sorbate, Sorbent, Sorption, Sorption, Sorption Capacity, Sorption Kinetics, Stability, Wastewater, Wastewaters

? Behnajady, M.A., Modirshahla, N., Mirzamohammady, M., Vahid, B. and Behnajady, B. (2008), Increasing photoactivity of titanium dioxide immobilized on glass plate with optimization of heat attachment method parameters. Journal of Hazardous Materials, 160 (2-3), 508-513.

Full Text: 2008\J Haz Mat160, 508.pdf

Abstract: In the present work the optimization of heat attachment method for increasing photoactivity of immobilized TiO₂ on glass plate was investigated. Results show that sonication time, TiO₂ suspension dosage, immobilization temperature, solvent type and immobilization replications are very effective on the photoactivity of immobilized TiO₂ on glass plate on the removal of C.I. Acid Red 88 (AR88) and optimizing these parameters increases the photoactivity of immobilized catalyst. In other step, the effect of operational parameters such as light intensity and initial concentration of AR88 on the removal of AR88 was investigated with four times immobilized TiO₂ on glass plate. Results show that removal rate decreases with increasing initial concentration of AR88 but increases with increasing UV-light intensity.

Keywords: C.I. Acid Red 88, Catalyst, Concentration, Glass, Heat Attachment Method, Heterogenous Photocatalysis, Immobilization, Immobilized, Immobilized Photocatalyst, Optimization, Removal, Sonication, Suspension, Temperature, TiO₂, Titanium, Titanium Dioxide, UV Light, Work

? Krishna, K.R. and Philip, L. (2008), Adsorption and desorption characteristics of lindane, carbofuran and methyl parathion on various Indian soils. Journal of Hazardous Materials, 160 (2-3), 559-567.

Full Text: 2008\J Haz Mat160, 559.pdf

Abstract: Adsorption and desorption characteristics of three insecticides on four Indian soils were studied. Insecticides used were representative of organochlorine, organo phosphate. and carbomate groups. The order of adsorption of pesticides on soils was: lindane > methyl parathion > carbofuran. Compost soil had shown the maximum adsorption capacity. The order of adsorption capacity of various soils were: compost soil > clayey soil > red soil > sandy soil. Adsorption isotherms were better fitted to Freundlich model and K-f values increased with increase in organic matter content of the soils. Thermodynamic parameters indicated favorable adsorption of all the three pesticides in four different soils. Adsorption was exothermic in nature. Distilled water desorbed 30-60% of adsorbed pesticides whereas; organic solvents were able to affect 50-80% of sorbed pesticides. Clay content and organic matter played a significant role in pesticide adsorption and desorption processes. Hysteresis effect was observed in red, clayey and compost soils. Hysteresis effect increased with increase in organic matter and clay content of the soils. (C) 2008 Published by Elsevier B.V.

Keywords: Lindane, Methyl Parathion, Carbofuran, Sorption, Soil, Clay, Organic Content, Equilibrium Assessments, Water Solubility, Pesticides, Sorption, Endosulfan, Movement, Sediment, Samples, pH

? Hameed, B.H. and Rahman, A.A. (2008), Removal of phenol from aqueous solutions by adsorption onto activated carbon prepared from biomass material. Journal of Hazardous Materials, 160 (2-3), 576-581.

Full Text: 2008\J Haz Mat160, 576.pdf

Abstract: Activated carbon derived from rattan sawdust (ACR) was evaluated for its ability to remove phenol from an aqueous solution in a batch process. Equilibrium studies were conducted in the range of 25-200 mg/L initial phenol concentrations, 3-10 solution pH and at temperature of 30C. The experimental data were analyzed by the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. Equilibrium data fitted well to the Langmuir model with a maximum adsorption capacity of 149.25 mg/g. The dimensionless separation factor R-L revealed the favorable nature of the isotherm of the phenol-activated carbon system. The pseudo-second-order kinetic model best described the adsorption process. The results proved that the prepared activated carbon was an effective adsorbent for removal of phenol from aqueous solution. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorbent, Adsorption, Adsorption Capacity, Adsorption Isotherm, Adsorption Process, Agricultural Waste, Aqueous Solution, Aqueous Solutions, Basic Dye, Batch, Batch Process, Biomass, Capacity, Carbon, Data, Equilibrium, Equilibrium Studies, Experimental, Fly-Ash, Freundlich, Isotherm, Isotherm Models, Kinetic, Kinetic Model, Kinetics, Kinetics, Langmuir, Langmuir Model, Liquid-Phase Adsorption, Methylene-Blue, Model, Models, pH, Phenol, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Kinetic Model, Rattan Sawdust, Removal, Rights, Sawdust, Seed Coat, Separation, Solution, Solutions, Sorption, Temperature, Water

? Epolito, W.J., Yang, H., Bottomley, L.A. and Pavlostathis, S.G. (2008), Kinetics of zero-valent iron reductive transformation of the anthraquinone dye Reactive Blue 4. Journal of Hazardous Materials, 160 (2-3), 594-600.

Full Text: 2008\J Haz Mat160, 594.pdf

Abstract: The effect of operational conditions and initial dye concentration on the reductive transformation (decolorization) of the textile dye Reactive Blue 4 (RB4) using zero-valent iron (ZVI) filings was evaluated in batch assays. The decolorization rate increased with decreasing pH and increasing temperature, mixing intensity, and addition of salt (100 g L(-1) NaCl) and base (3 g L(-1) Na(2)CO(3) and 1 g L(-1) NaOH), conditions typical of textile reactive dyebaths, ZVI RB4 decolorization kinetics at a single initial dye concentration were evaluated using a pseudo first-order model. Under dyebath conditions and at an initial RB4 concentration of 1000 mg L(-1), the pseudo first-order rate constant (k(obs)) was 0.029 +/- 0.006 h(-1), corresponding to a half-life of 24.2 h and a ZVI surface area-normalized rate constant (k(SA)) of 2.9 x 10(-4) L m(-2) h(-1). However, as the initial dye concentration increased, the k(obs) decreased, suggesting saturation of ZVI surface reactive sites. Non-linear regression of initial decolorization rate values as a function of initial dye concentration, based on a reactive sites saturation model, resulted in a maximum decolorization rate (V(m)) of 720 +/- 88 mg L(-1) h(-1) and a half-saturation constant (K) of 1299 +/- 273 mg L(-1). Decolorization of RB4 via a reductive transformation, which was essentially irreversible (2-5% re-oxidation), is believed to be the dominant decolorization mechanism. However, some degree of RB4 irreversible sorption cannot be completely discounted. The results of this study show that ZVI treatment is a promising technology for the decolorization of commercial, anthraquinone-bearing, spent reactive dyebaths. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Anthraquinone Dyes, Aqueous-Solution, Azo-Dye, Carbon-Tetrachloride, Decolorization, Decolorization, Degradation, First Order, Granular Iron, Iron, Kinetics, Mechanism, Metal, Methanogenic Conditions, Model, pH, Pseudo-First-Order, Rate Constant, Reactive Dyes, Sorption, Textile Dyes, Treatment, Waste-Water, Zero-Valent Iron, Zerovalent Iron

? Wang, L.Z., Zhao, Y.M. and Fu, J.F. (2008), The influence of TiO₂ and aeration on the kinetics of electrochemical oxidation of phenol in packed bed reactor. Journal of Hazardous Materials, 160 (2-3), 608-613.

Full Text: 2008\J Haz Mat160, 608.pdf

Abstract: The electrochemical oxidation of phenolic wastewater in a lab-scale reactor, packed into granular activated carbon (GAC) with Ti/SnO(2) anodes and stainless steel cathodes, was interpreted in this study. GAC saturated rapidly if it was only used as sorbent, but application of suitable electric energy for the system simultaneously could recover the adsorption ability of GAC and maintain the continuous running effectively. The titanium dioxide (TiO₂) as catalyst and airflow were also applied to the electrochemical reactor to examine the enhancement for phenol oxidation process. Results revealed that the electrochemical degradation of phenol could be reasonably described by first-order kinetics. In addition, it was illustrated that acid region, increased voltage, more dosage of TiO₂ and higher aeration intensity were all beneficial parameters for phenol oxidation rates. By inspecting the relationship between the rate constants (k) and influencing factors. respectively, an overall kinetic model for phenol oxidation was proposed. The kinetics obtained from the experiments under corresponding electrochemical conditions could provide an accurate estimation of phenol concentration effluent and better design of the packed bed reactor. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Aeration, Degradation, Design, Electrochemical Oxidation, Electrodes, Energy, Fenton Oxidation, First Order, GAC, Granular Activated Carbon, Hydrogen-Peroxide, Ion, Iron, Kinetic, Kinetic Model, Kinetics, Model, Nanoparticles, Oxidation, Packed Bed, Packed Bed Reactor (PBR), Phenol, Photocatalytic Oxidation, Rate Constants, Removal, Sorbent, TiO₂, Titanium Dioxide, Waste-Water, Wastewater

? Wang, T.H., Li, M.H., Yeh, W.C., Wei, Y.Y. and Teng, S.P. (2008), Removal of cesium ions from aqueous solution by adsorption onto local Taiwan laterite. Journal of Hazardous Materials, 160 (2-3), 638-642.

Full Text: 2008\J Haz Mat160, 638.pdf

Abstract: Utilization of local Taiwan laterite (LTL) to remove aqueous cesium was investigated in this work under the conditions of various contact time, cesium (Cs) loading and temperature. Experimental results show that adsorption is instantaneous. Freundlich and Langmuir simulation results demonstrate that local Taiwan laterite has high affinity and sorption capacity for Cs at low temperatures, which may be attributed to enhanced desorption as temperature increased. Thermodynamic parameters including Delta H, Delta G and Delta S were calculated and it is indicated that Cs adsorption on LTL is an exothermic, spontaneous and physical adsorption reaction. Moreover, the adsorbed Cs is distributed evenly on the LTL surface, which is confirmed by SEM/EDS mapping images. Furthermore, the absence of apparent shifting or broadening of the kaolinite signal in XRD patterns after Cs adsorption is an indication of the non-expanding characteristic of kaolinite structure. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Bentonite, Cs+ Sorption, Desorption, Freundlich, Goethite, Hanford Site, Immobilization, Indication, Isotherm, Kaolinite, Langmuir, Laterite, Minerals, Natural Kaolinite, Radionuclides, Safety Assessment, Sorption, Spontaneous, Subsurface Sediments, Surface Distribution, Temperature, Waste, Zeolite

? Fan, T., Liu, Y.G., Feng, B.Y., Zeng, G.M., Yang, C.P., Zhou, M., Zhou, H.Z., Tan, Z.F. and Wang, X. (2008), Biosorption of cadmium(II), zinc(II) and Lead(II) by Penicillium simplicissimum: Isotherms, kinetics and thermodynamics. Journal of Hazardous Materials, 160 (2-3), 655-661.

Full Text: 2008\J Haz Mat160, 665.pdf

Abstract: The isotherms, kinetics and thermodynamics of Cd(II), Zn(II) and Pb(II) biosorption by Penicillium simplicissimum were investigated in a batch system. The effects of pH, initial metal ions concentration, biomass dose, contact time, temperature and co-ions on the biosorption were studied. Adsorption data were well described by both the Redlich-Peterson and Langmuir model. Chemical ion-exchange was found to be an important process based on free energy value from Dubini-Radushkevich isotherm for all metal ions. The results of the kinetic studies of all metal ions at different temperature showed that the rate of adsorption followed the pseudo second-order kinetics well. The thermodynamics constants G, H, and S, of the adsorption process showed that biosorption of Cd(II), Zn(II) and Pb(H) ions on Penicillium simplicissimum were endothermic and spontaneous. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Process, Aqueous-Solutions, Aspergillus-Niger, Batch, Batch System, Biomass, Biosorption, Cadmium(II), Cd(II), Chromium(VI), Concentration, Copper(II), Data, Endothermic, Energy, Equilibrium, Ion Exchange, Ion-Exchange, Ionexchange, Ions, Isotherm, Isotherms, Kinetic, Kinetic Studies, Kinetics, Kinetics and Thermodynamics, Langmuir, Langmuir Model, Lead(II), Metal, Metal Ions, Metal-Ions, Model, Pb(II), Penicillium Simplicissimum, pH, Pseudo Second Order, Pseudo Second Order Kinetics, Pseudo Second-Order, Pseudo-Second-Order, Redlich-Peterson, Removal, Rights, Second Order, Second Order Kinetics, Second-Order, Second-Order Kinetics, Spontaneous, Temperature, Thermodynamics, Value, Zinc(II), Zn(II)

? Gerçel, Ö., Gerçel, H.F., Koparal, A.S. and Öğütveren, Ü.B. (2008), Removal of disperse dye from aqueous solution by novel adsorbent prepared from biomass plant material. Journal of Hazardous Materials,