Personal Research Database

Full Text: 2008\J Haz Mat157, 209.pdf

Abstract: Various methods to prepare and characterize TiO₂ photocatalyst loaded onto activated carbon (AC) support have been developed over the last decade. This photocatalyst has been used in a variety of investigations, i.e. from water decontamination to direct pollutant degradation in aqueous and gas phase systems using UV irradiation and lately with the assistance of ultrasonic sound waves. Chemical vapor deposition (CVD) method is one of the most promising and well-researched methods for deposition of catalysts onto supports. Given its advantage, from an engineering and fundamental aspect, CVD method also has commercial applications. A detailed search of published reports of these investigations was carried out and analyzed in this paper with focus on CVD techniques, activated carbon support and sonication.

Keywords: Activated Carbon, Carbon, Chemical, Chemical Vapor Deposition, Decontamination, Degradation, Deposition, Engineering, Investigations, Irradiation, Methods, Review, Sonication, Sonophotocatalysis, Support, Systems, Techniques, TiO₂, Titanium, Titanium Dioxide, Ultrasonic, UV, Water

? Demirbas, A. (2008), Heavy metal adsorption onto agro-based waste materials: A review. Journal of Hazardous Materials, 157 (2-3), 220-229.

Full Text: 2008\J Haz Mat157, 220.pdf

Abstract: Adsorption has been proved to be an excellent way to treat industrial waste effluents, offering significant advantages like the low-cost, availability, profitability, easy of operation and efficiency. Biosorption of heavy metals from aqueous solutions is a relatively new process that has proven very promising in the removal of contaminants from aqueous effluents. Biosorption is becoming a potential alternative to the existing technologies for the removal and/or recovery of toxic metals from wastewater. The major advantages of biosorption technology are its effectiveness in reducing the concentration of heavy metal ions to very low levels and the use of inexpensive biosorbent materials. Metal adsorption and biosorption onto agricultural wastes is a rather complex process affected by several factors. Mechanisms involved in the biosorption process include chemisorption, complexation, adsorption-complexation on surface and pores, ion exchange, microprecipitation, heavy metal hydroxide condensation onto the biosurface, and surface adsorption.

Keywords: Adsorption, Agricultural, Agricultural Wastes, Agro Waste Material, Alternative, Aqueous Solutions, Availability, Biosorbent, Biosorption, Chemisorption, Complexation, Concentration, Contaminants, Effectiveness, Efficiency, Effluents, Heavy Metal, Heavy Metal Ion, Heavy Metal Ions, Heavy Metals, Ion Exchange, Ion-Exchange, Ions, Low Cost, Mechanisms, Metal, Metal Adsorption, Metal Ions, Metals, Operation, Potential, Recovery, Removal, Review, Solutions, Surface, Technologies, Technology, Toxic, Toxic Metals, Waste, Waste Materials, Wastewater

? Şengil, İ.A. and Özacar, M. (2008), Biosorption of Cu(II) from aqueous solutions by mimosa tannin gel. Journal of Hazardous Materials, 157 (2-3), 277-285.

Full Text: 2008\J Haz Mat157, 277.pdf

Abstract: The biosorption of Cu(II) from aqueous solutions by mimosa tannin resin (MTR) was investigated as a function of particle size, initial pH, contact time and initial metal ion concentration. The aim of this study was to understand the mechanisms that govern copper removal and find a suitable equilibrium isotherm and kinetic model for the copper removal in a batch reactor. The experimental isotherm data were analysed using the Langmuir, Freundlich and Temkin equations. The equilibrium data fit well in the Langmiur isotherm. The experimental data were analysed using four sorption kinetic models - the pseudo-first- and second-order equations, and the Elovich and the intraparticle diffusion equation - to determine the best fit equation for the biosorption of copper ions onto mimosa tannin resin. Results show that the pseudo-second-order equation provides the best correlation for the biosorption process, whereas the Elovich equation also fits the experimental data well. Thermodynamic parameters such as the entropy change, enthalpy change and Gibb’s free energy change were found out to be 153.0 J mol^-1 K^-1, 42.09 kJ mol^-1 and -2.47 kJ mol^-1, respectively. (c) 2008 Elsevier B.V. All rights reserved.

Keywords: Aqueous Solutions, Batch, Batch Reactor, Biosorption, Concentration, Copper, Copper Removal, Copper(II), Correlation, Cu(II), Data, Diffusion, Elovich, Elovich Equation, Energy, Enthalpy, Entropy, Equilibrium, Equilibrium Isotherm, Experimental, Freundlich, Function, Gel, Intraparticle Diffusion, Isotherm, Kinetic, Kinetic Model, Kinetic Models, Langmuir, Mechanisms, Metal, Mimosa Tannin Gel, Model, Models, Particle Size, pH, Pseudo Second Order, Pseudo-Second-Order, Removal, Resin, Second Order, Second-Order, Size, Solutions, Sorption, Thermodynamic, Thermodynamic Parameters

? Pan, B.J., Pan, B.C., Zhang, W.M., Zhang, Q.R., Zhang, Q.X. and Zheng, S.R. (2008), Adsorptive removal of phenol from aqueous phase by using a porous acrylic ester polymer. Journal of Hazardous Materials, 157 (2-3), 293-299.

Full Text: 2008\J Haz Mat157, 293.pdf

Abstract: The removal of phenol from aqueous solution was examined by using a porous acrylic ester polymer (Amberlite XAD-7) as an adsorbent. Favorable phenol adsorption was observed at acidic solution pH and further increase of solution pH results in a marked decrease of adsorption capacity, and the coexisting inorganic salt NaCl exerts positive effect on the adsorption process. Adsorption isotherms of phenol were linearly correlated and found to be well represented by either the Langmuir or Freundlich isotherm model. Thermodynamic parameters such as changes in the enthalpy (H), entropy (S) and free energy (G) indicate that phenol adsorption onto XAD-7 is an exothermic and spontaneous process in nature, and lower ambient temperature results in more favorable adsorption. Kinetic experiments at different initial solute concentrations were investigated and the pseudo-second-order kinetic model was successfully represented the kinetic data. Additionally, the column adsorption result showed that a complete removal of phenol from aqueous phase can be achieved by XAD-7 beads and the exhausted adsorbent was amenable to an entire regeneration by using ethanol as the regenerant. More interestingly, relatively more volume of hot water in place of ethanol can also achieve a similar result for repeated use of the adsorbent. (c) 2008 Elsevier B.V. All rights reserved.

Keywords: Acrylic Ester Polymer, Adsorbent, Adsorption, Adsorption Capacity, Adsorption Isotherms, Aqueous Phase, Aqueous Solution, Beads, Capacity, Changes, Column, Data, Energy, Enthalpy, Entropy, Ethanol, Exothermic, Experiments, Freundlich, Freundlich Isotherm, Isotherm, Isotherm Model, Isotherms, Kinetic, Kinetic Model, Kinetics, Langmuir, Model, NaCl, pH, Phenol, Polymer, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Kinetic Model, Regeneration, Removal, Salt, Solution, Temperature, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Volume, Water

? Hameed, B.H. and El-Khaiary, M.I. (2008), Equilibrium, kinetics and mechanism of malachite green adsorption on activated carbon prepared from bamboo by K₂CO₃ activation and subsequent gasification with CO₂. Journal of Hazardous Materials, 157 (2-3), 344-351.

Full Text: 2008\J Haz Mat157, 344.pdf

Abstract: In this work, the adsorption of malachite green (MG) was studied on activated carbon prepared from bamboo by chemical activation with K₂CO₃ and physical activation with CO₂ (BAC). Adsorption studies were conducted in the range of 25-300 mg/L initial MG concentration and at temperature of 30C. The experimental data were analyzed by the Freundlich isotherm, the Langmuir isotherm, and the multilayer adsorption isotherm. Equilibrium data fitted well with the Langmuir model with maximum adsorption capacity of 263.58 mg/g. The rates of adsorption were found to confirm to pseudo-second-order kinetics with good correlation and the overall rate of dye uptake was found to be controlled by pore diffusion throughout the entire adsorption period. The results indicate that the BAC could be used to effectively adsorb MG from aqueous solutions. (c) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Activation, Adsorption, Adsorption Capacity, Adsorption Isotherm, Aqueous Solutions, Bamboo, Capacity, Carbon, Chemical, Chemical Activation, CO₂, Concentration, Correlation, Data, Diffusion, Dye, Equilibrium, Experimental, Freundlich, Freundlich Isotherm, Isotherm, Kinetics, Langmuir, Langmuir Isotherm, Langmuir Model, Malachite Green, Mechanism, Mg, Model, Multilayer, Physical, Physical Activation, Pore Diffusion, Pseudo Second Order, Pseudo Second Order Kinetics, Pseudo-Second-Order, Pseudo-Second-Order Kinetics, Rates, Solutions, Temperature, Uptake, Work

? Zhang, L., Huang, T., Zhang, M., Guo, X.J. and Yuan, Z. (2008), Studies on the capability and behavior of adsorption of thallium on nano-Al₂O₃. Journal of Hazardous Materials, 157 (2-3), 352-357.

Full Text: 2008\J Haz Mat157, 352.pdf

Abstract: A novel sorbent, nano-Al₂O₃ was employed for the removal of thallium from aqueous solution in batch equilibrium experiments, in order to investigate its adsorption properties. The removal percentage of thallium by the sorbent increased with increasing pH from 1 to 5. The adsorption capacities and removal percentage of Tl(III) onto nano-Al₂O₃ were evaluated as a function of the solution concentration and temperature. Results have been analyzed by the Langmuir, Freundlich adsorption isotherms. Adsorption isothermal data could be well interpreted by the Langmuir model. The mean energy of adsorption 9.32kJ mol^-1 was calculated from the Dubinin-Radushkevich (D-R) adsorption isotherm. The kinetic experimental data properly correlated with the second-order kinetic model. The thermodynamic parameters for the process of adsorption have been estimated. The H and G values of thallium(III) adsorption on nano-Al₂O₃ showed endothermic adsorption. (c) 2008 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Capacities, Adsorption Isotherm, Adsorption Isotherms, Adsorption Properties, Aqueous Solution, Aqueous-Solutions, Behavior, Concentration, Data, Endothermic, Energy, Equilibrium, Experimental, Experiments, Freundlich, Function, Isotherm, Isothermal, Isotherms, Kinetic, Kinetic Model, Kinetics, Langmuir, Langmuir Model, Metal-Ions, Model, Nano-Al₂O₃, pH, Removal, Rights, Second Order, Second-Order, Solution, Solvent-Extraction, Sorbent, Temperature, Thallium, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Tl(III)

? Wang, X.S., Zhou, Y., Jiang, Y. and Sun, C. (2008), The removal of basic dyes from aqueous solutions using agricultural by-products. Journal of Hazardous Materials, 157 (2-3), 374-385.

Full Text: 2008\J Haz Mat157, 374.pdf

Abstract: The adsorption of two basic dyes, namely, Malachite Green and Methylene Blue onto both agricultural by-products (i.e. rice bran and wheat bran) has been investigated in this study. The adsorption of both basic dyes was solution pH-dependent. The kinetic experimental data were analyzed using four kinetic equations including pseudo-first-order equation, pseudo-second-order equation, external diffusion model and intraparticle diffusion model to examine the mechanism of adsorption and potential rate-controlling step. The best-fit equation was identified using normalized standard deviation. The Langmuir and Freundich isotherms were used to fit the equilibrium data and the results showed that the Langmuir isotherm exhibited a little better fit to the Methylene Blue adsorption data by both adsorbents while the Freundlich isotherm seemed to agree better with the Malachite Green adsorption. The Gibbs free energy changes at 20C were calculated and the obtained values supported the conclusion that two dyes molecules adsorbed by physical processes. The effects of particle size, adsorbent concentration and solution ionic strength on the adsorption of the two basic dyes were also studied. (c) 2008 Elsevier B.V. All rights reserved.

Keywords: Adsorbent, Adsorbents, Adsorption, Agricultural, Agricultural By-Products, Aqueous Solutions, Basic Dyes, Biosorption, Changes, Concentration, Data, Diffusion, Diffusion Model, Dyes, Energy, Equilibrium, Experimental, Freundlich, Freundlich Isotherm, Gibbs Free Energy, Intraparticle Diffusion, Intraparticle Diffusion Model, Ionic Strength, Isotherm, Isotherms, Kinetic, Kinetic Equations, Kinetic Modeling, Langmuir, Langmuir Isotherm, Malachite Green, Malachite-Green, Mechanism, Mechanism of Adsorption, Methylene Blue, Model, Particle Size, pH-Dependent, Physical, Potential, Pseudo First Order, Pseudo Second Order, Pseudo-First-Order, Pseudo-First-Order Equation, Pseudo-Second-Order, Pseudo-Second-Order Equation, Removal, Rice, Rice Bran, Size, Solution, Solutions, Standard, Strength, Wheat Bran

? Unuabonah, E.I., Adebowale, K.O. and Dawodu, F.A. (2008), Equilibrium, kinetic and sorber design studies on the adsorption of Aniline blue dye by sodium tetraborate-modified Kaolinite clay adsorbent. Journal of Hazardous Materials, 157 (2-3), 397-409.

Full Text: 2008\J Haz Mat157, 397.pdf

Abstract: Raw Kaolinite clay obtained Ubulu-Ukwu, Delta State of Nigeria and its sodium tetraborate (NTB)-modified analogue was used to adsorb Aniline blue dye. Fourier transformed infrared spectra of NTB-modified Kaolinite suggests that modification was effective on the surface of the Kaolinite clay with the strong presence of inner-OH functional group. The modification of Kaolinite clay raised its adsorption capacity from 1666 to 2000 mg/kg. Modeling adsorption data obtained from both unmodified and NTB-modified Kaolinite clay reveals that the adsorption of Aniline blue dye on unmodified Kaolinite clay is on heterogeneous adsorption sites because it followed strongly the Freundlich isotherm equation model while adsorption data from NTB-modified Kaolinite clay followed strongly the Langmuir isotherm equation model which suggest that Aniline blue dye was adsorb homogeneous adsorption sites on the NTB-modified adsorbent surface. There was an observed increase in the amount of Aniline blue adsorbed as initial dye concentration was increased from 10 to 30 mg/L. It was observed that kinetic data obtained generally gave better robust fit to the second-order kinetic model (SOM). The initial sorption rate was found to increased with increasing initial dye concentration (from 10 to 20 mg/L) for data obtained from 909 to 1111 mg kg^-1 min^-1 for unmodified and 3325-5000 mg kg^-1 min^-1 for NTB-modified adsorbents. Thereafter there was a decrease in initial sorption rate with further increase in dye concentration. The linearity of the plots of the pseudo-second-order model with very high-correlation coefficients indicates that chemisorption is involved in the adsorption process. From the design of a single-batch adsorber it is predicted that the NTB-modified Kaolinite clay adsorbent will require 50% less of the adsorbent to treat certain volumes of wastewater containing 30 mg/L of Aniline blue dye when it is compared with the unmodified adsorbent. This will be cost effective in the use of NTB-modified adsorbent for the adsorption of Aniline blue dye from water and wastewater. (c) 2008 Elsevier B. V. All rights reserved.

Keywords: Adsorbent, Adsorbents, Adsorption, Adsorption Capacity, Adsorption Process, Aniline Blue, Capacity, Chemisorption, Clay, Concentration, Cost, Cost-Effective, Data, Design, Dye, Equilibrium, Freundlich, Freundlich Isotherm, Functional Group, Isotherm, Kaolinite, Kaolinite Clay, Kinetic, Kinetic Model, Langmuir, Langmuir Isotherm, Model, Modeling, Modification, Modified, Nigeria, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Model, Second Order, Second-Order, Sodium, Sorption, Surface, Wastewater, Water

? Sari, A. and Tüzen, M. (2008), Biosorption of cadmium(II) from aqueous solution by red algae (Ceramium virgatum): Equilibrium, kinetic and thermodynamic studies. Journal of Hazardous Materials, 157 (2-3), 448-454.

Full Text: 2008\J Haz Mat157, 448.pdf

Abstract: The biosorption characteristics of Cd(II) ions using the red alga (Ceramium virgatum) were investigated. Experimental parameters affecting the 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. The biosorption capacity of C. virgatum biomass for Cd(II) ions was found to be 39.7 mg/g. From the D-R isotherm model, the mean free energy was calculated as 12.7 kJ/mol, indicating that the biosorption of Cd(II) the metal ions was taken place by chemisorption. The calculated thermodynamic parameters (G, H and S) showed that the biosorption of Cd(II) ions onto C. virgatum was feasible, spontaneous and exothermic at 293-323 K. Evaluation of experimental data in terms of biosorption kinetics showed that the biosorption of Cd(II) C. virgatum followed well pseudo-second-order kinetics. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Algae, Aqueous Solution, Biomass, Biosorption, Biosorption Characteristics, Biosorption Isotherms, Biosorption Kinetics, Cadmium(II), Capacity, Cd(II), Cd(II) Ions, Ceramium Virgatum, Characteristics, Chemisorption, D-R Isotherm, Data, Energy, Equilibrium, Exothermic, Experimental, Freundlich, Isotherm, Isotherm Model, Isotherms, Kinetic, Kinetics, Langmuir, Metal, Metal Ions, Model, Models, pH, Pseudo Second Order, Pseudo Second Order Kinetics, Pseudo-Second-Order, Pseudo-Second-Order Kinetics, Solution, Temperature, Thermodynamic, Thermodynamic Parameters, Thermodynamic Studies, Thermodynamics

? Oguz, E., Tortum, A. and Keskinler, B. (2008), Determination of the apparent rate constants of the degradation of humic substances by ozonation and modeling of the removal of humic substances from the aqueous solutions with neural network. Journal of Hazardous Materials, 157 (2-3), 455-463.

Full Text: 2008\J Haz Mat157, 455.pdf

Abstract: In this study, the degradation rate constants of humic substances by ozonation under the different empirical conditions such as ozone-air flow rate, ozone generation potential, pH, temperature, powdered activated carbon (PAC) dosage and HCO3- ions concentration were determined. The ozonation of humic substances in the semi-batch reactor was found to fit pseudo-first-order reaction. The values of apparent rate constant of humic substances degradation increased with the increase of initial ozone-air flow rates, ozone generation potential, pH, temperatures and PAC dosage, but decreased with the increase of HCO3- concentration of the solution: Using Arrhenius equation, the activation energy (E) of the reaction was found as 1.96 kJ mol(-1). The reaction of ozonation of humic substances under the different temperatures was defined as diffusion control according to E.. The model based on artificial neural network (ANN) could predict the concentrations of humic substances removal from aqueous solution during ozonation. A relationship between the predicted results of the designed ANN model and experimental data was also conducted. The ANN model yielded determination coefficient of (R-2=0.995), standard deviation ratio (0.065), mean absolute error (4.057) and root mean square error (5.4967). (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Activation, Adsorption, Apparent Rate Constants, Coagulation, Control, Cr-L Dye, Diffusion, Drinking-Water, Energy, Experimental, Humic Substances, Ions, Model, Modeling, Neural Network, O-3, Ozonation, Ozone, PAC, Parameters, pH, Powdered Activated Carbon, Pseudo-First-Order, Rate Constant, Ratio, Removal

? Shedbalkar, U., Dhanve, R. and Jadhav, J. (2008), Biodegradation of triphenylmethane dye cotton blue by Penicillium ochrochloron MTCC 517. Journal of Hazardous Materials, 157 (2-3), 472-479.

Full Text: 2008\J Haz Mat157, 472.pdf

Abstract: Triphenylmethane dyes belong to the most important group of synthetic colorants and are used extensively in the textile industries for dying cotton, wool, silk, nylon, etc. They are generally considered as the xenobiotic compounds, which are very recalcitrant to biodegradation. Penicillium ochrochloron decolorizes cotton blue (50 mg g^-1) within 2.5 h under static condition at pH 6.5 and temperature 25C. TLC, FTIR and HPLC analysis confirms biodegradation of cotton blue. FTIR spectroscopy and GC-MS analysis indicated sulphonamide and triphenylmethane as the final products of cotton blue degradation. The pH, temperature and maturity of biomass affected the rate of decolorization. Presence of lignin peroxidase, tyrosinase and aminopyrine N-demethylase activities in the cell homogenate as well as increase in the extracellular activity of lignin peroxidase suggests the role of these enzymes in the decolorization process. The phytotoxicity and microbial toxicity studies of extracted metabolites suggest the less toxic nature of them.

Keywords: Aminopyrine N-Demethylase, Analysis, Biodegradation, Biomass, Cotton Blue, Decolorization, Degradation, Dye, Dyes, Dying, FTIR, FTIR Spectroscopy, GC-MS, GCMS, HPLC, Lignin, Lignin Peroxidase, Metabolites, Microbial, Penicillium Ochrochloron, pH, Role, Spectroscopy, Temperature, Toxic, Toxicity, Triphenylmethane, Triphenylmethane Dye, Tyrosinase

? Zheng, W., Li, X.M., Wang, F., Yang, Q., Deng, P. and Zeng, G.M. (2008), Adsorption removal of cadmium and copper from aqueous solution by areca - A food waste. Journal of Hazardous Materials, 157 (2-3), 490-495.

Full Text: 2008\J Haz Mat157, 490.pdf

Abstract: Areca waste (AW) has been investigated as metal biosorbent for cadmium and copper from aqueous solution for its availability as food waste and also for its cellulosic matrix rich of potential metal binding active sites. The effect of various parameters on adsorption process such as contact time, solution pH, amount of AW and initial concentration of metal ions was studied at room temperature to optimize the conditions for maximum adsorption. Maximum metal sorption was found to occur at pH 5.6. Adsorption process revealed that the initial uptake was rapid and equilibrium was established about in 1 h for cadmium and copper. The equilibrium sorption data for single metal systems at pH 5.6 were described by the Langmuir, Freundlich and D-R isotherm models. The adsorption isotherm studies clearly indicated that the adsorptive behaviour of metal ions on AW not only the Langmuir assumptions but also the Freundlich and the D-R assumptions. The highest value of Langmuir maximum uptake, (b), was found for cadmium (1.12 mg, g) and copper (2.84 mg, g). Similar Freundlich empirical constants, K, were obtained for cadmium (1.086) and copper (1.119). Ion-exchange and surface adsorption might be involved in the adsorption process of cadmium and copper. Desorption studies revealed that cadmium and copper can be easily removed from AW by altering the pH values of the solution using HNO₃, indicating that AW are a promising adsorbent for wastewater treatment. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorbent, Adsorption, Adsorption Isotherm, Adsorption Process, Aqueous Solution, Areca, Assumptions, Availability, Behaviour, Binding, Biosorbent, Cadmium, Concentration, Contact, Copper, Cu(II), D-R Isotherm, Data, Desorption, Empirical, Equilibrium, Food, Food Waste, Freundlich, HNO₃, Ion Exchange, Ion-Exchange, Ions, Isotherm, Isotherm Models, Kinetics, Langmuir, Lead, Matrix, Metal, Metal Ions, Metal Sorption, Metal-Ions, Models, Nickel, pH, Potential, Process, Rapid, Removal, Rights, Room Temperature, Sawdust, Single, Solution, Sorption, Surface, Systems, Temperature, Time, Treatment, Uptake, Value, Values, Waste, Wastewater, Wastewater Treatment, Water

? Lata, H., Garg, V.K. and Gupta, R.K. (2008), Sequestration of nickel from aqueous solution onto activated carbon prepared from Parthenium hysterophorus L. Journal of Hazardous Materials,