Personal Research Database

Full Text: 2007\J Haz Mat146, 214.pdf

Abstract: Batch experiments were carried out for the sorption of methylene blue onto Paspalum notatum. The operating variables studied were initial dye concentration, initial solution pH, adsorbent dosage and contact time. Experimental equilibrium data were fitted to Freundlich, Langmuir and Redlich–Peterson isotherms by non-linear regression method. Six error functions was used to determine the optimum isotherm by non-linear regression method. The present study shows r² as the best error function to determine the parameters involved in both two- and three-parameter isotherms. Langmuir isotherm was found to be the optimum isotherm for methylene blue onto P. notatum. The monolayer methylene blue sorption capacity of P. notatum was found to be 31 mg/g. The kinetics of methylene blue onto P. notatum was found to follow a pseudo second order kinetics. A Boyd plot confirms the external mass transfer as the rate-limiting step in the dye sorption process. The influence of initial dye concentration on the dye sorption process was represented in the form of dimensionless mass transfer numbers (Sh/Sc0.33) and was found to vary as C0-510^-6.

Keywords: Activated Carbon, Adsorbent, Adsorbent Dosage, Adsorption, Aqueous-Solution, Basic-Dyes, Biosorption, Capacity, Concentration, Contact Time, Dosage, Dye, Dye Sorption, Equilibrium, Equilibrium Data, Equilibrium Studies, Error Function, Experiments, External Mass Transfer, Fly-Ash, Freundlich, Function, Isotherm, Isotherm Analyses, Isotherms, Kinetics, Kinetics and Equilibrium, Langmuir, Langmuir Isotherm, Langmuir-Isotherm, Mass, Mass Transfer, Mass-Transfer, Mechanism, Method, Methylene Blue, Methylene Blue Sorption, Monolayer, Non-Linear, Non-Linear Regression, Nonlinear, Nonlinear Regression, Operating Variables, Order, P, Parameters, Paspalum Notatum, pH, Process, Pseudo Second Order, Pseudo Second Order Kinetics, Pseudo-Second-Order, Rate Limiting, Rate Limiting Step, Rate-Limiting Step, Redlich-Peterson, Redlich-Peterson Isotherms, Regression, Regression Method, Regression-Analysis, Removal, Second Order, Second Order Kinetics, Solution pH, Sorption, Sorption Capacity, Three-Parameter Isotherms, Time, Transfer, Water

? Wibowo, N., Setyadhi, L., Wibowo, D., Setiawan, J. and Ismadji, S. (2007), Adsorption of benzene and toluene from aqueous solutions onto activated carbon and its acid and heat treated forms: Influence of surface chemistry on adsorption. Journal of Hazardous Materials, 146 (1-2), 237-242.

Full Text: 2007\J Haz Mat146, 237.pdf

Abstract: The influence of surface chemistry and solution pH on the adsorption of benzene and toluene on activated carbon and its acid and heat treated forms were studied. A commercial coal-based activated carbon F-400 was chosen as carbon parent. The carbon samples were obtained by modification of F-400 by means of chemical treatment with HNO₃ and thermal treatment under nitrogen flow. The treatment with nitric acid caused the introduction of a significant number of oxygenated acidic surface groups onto the carbon surface, while the heat treatment increases the basicity of carbon. The pore characteristics were not significantly changed after these modifications. The dispersive interactions are the most important factor in this adsorption process. Activated carbon with low oxygenated acidic surface groups (F-400Tox) has the best adsorption capacity.

Keywords: Activated Carbon, Adsorption, Surface Chemistry, Benzene, Toluene

? Mittal, A., Kurup, L. and Mittal, J. (2007), Freundlich and Langmuir adsorption isotherms and kinetics for the removal of Tartrazine from aqueous solutions using hen feathers. Journal of Hazardous Materials, 146 (1-2), 243-248.

Full Text: 2007\J Haz Mat146, 243.pdf

Abstract: Tartrazine, a yellow menace, is widely being used in cosmetics, foodstuffs, medicines and textile. It is carcinogenic and also catalyzes allergic problems. In the present work the ability to remove Tartrazine from aqueous solutions has been studied using waste material—hen feathers, as adsorbent. Effects of pH, concentration of the dye, temperature and adsorbent dosage have been studied. Equilibrium isotherms for the adsorption of the dye were measured experimentally. Results were analyzed by the Freundlich and Langmuir equation at different temperatures and determined the characteristic parameters for each adsorption isotherm. The adsorption process has been found endothermic in nature and thermodynamic parameters, Gibb’s free energy (ΔG°), change in enthalpy (ΔH°) and change in entropy (ΔS°) have been calculated. The paper also includes results on the kinetic measurements of adsorption of the dye on hen feathers at different temperatures. By rate expression and treatment of data it has been established that the adsorption of Tartrazine over hen feathers follows a first-order kinetics and a film diffusion mechanism operates at all the temperatures.

Keywords: Adsorbent, Adsorbent Dosage, Adsorption, Adsorption Isotherm, Adsorption Isotherms, Adsorption Process, Aqueous Solutions, Concentration, Cosmetics, Data, Diffusion, Dye, Endothermic, Energy, Enthalpy, Entropy, Equilibrium, Equilibrium Isotherms, Expression, Film Diffusion, First Order, First-Order Kinetics, Freundlich, Hen Feathers, Isotherm, Isotherms, Kinetic, Kinetics, Langmuir, Langmuir Equation, Mechanism, pH, Removal, Solutions, Tartrazine, Temperature, Thermodynamic, Thermodynamic Parameters, Treatment, Waste, Work

? Özer, A. and Dursun, G. (2007), Removal of Methylene blue from aqueous solution by dehydrated wheat bran carbon. Journal of Hazardous Materials, 146 (1-2), 262-269.

Full Text: 2007\J Haz Mat146, 262.pdf

Abstract: Dyes are usually presents in the effluent water of many industries, such as textiles, leather, paper, printing and cosmetics. The effectiveness of dye adsorption from wastewater has made to get alternative different low cost adsorbent to other expensive treatment methods. The adsorption of methylene blue onto dehydrated wheat bran (DWB) was investigated at temperatures (25–45°C), initial methylene blue (MB) concentrations (100–500 mg L⁻¹) and adsorbent dosage at the given contact time for the removal of dye. The optimum adsorption conditions were found to be as medium pH of 2.5 and at the temperature of 45°C for the varying adsorbent dosage. Equilibrium isotherms were analysed by Freundlich, Langmuir and Redlich-Peterson isotherm equations using correlation coefficients. Adsorption data were well described by the Langmuir model, although they could be modelled by the Freundlich and Redlich-Peterson model as well. The pseudo-first order and pseudo-second order kinetic models were applied to test the experimental data. It was concluded that the pseudo-second order kinetic model provided better correlation of the experimental data rather than the pseudo-first order model. The mass transfer model as intraparticle diffusion was applied to the experimental data to examine the mechanisms of rate controlling step. It was found that at the higher initial MB concentration, intraparticle diffusion is becoming significant controlling step. The thermodynamic constants of the adsorption process were also evaluated by using the Langmuir constants related to the equilibrium of adsorption at temperatures varied in the range 25–55 °C.

Keywords: Activated Carbons, Adsorbent, Adsorbent Dosage, Adsorption, Adsorption, Adsorption Process, Aqueous Solution, Ash, Basic-Dyes, Batch, Carbon, Concentration, Concentrations, Constants, Contact Time, Correlation, Cost, Dehydrated Wheat Bran (DWB), Diffusion, Dosage, Dye, Dye Adsorption, Effectiveness, Effluent, Equations, Equilibrium, Equilibrium, Experimental, Experimental Data, Freundlich, Industries, Intraparticle Diffusion, Isotherm, Isotherms, Kinetic, Kinetic Model, Kinetic Models, Kinetics, Langmuir, Langmuir Constants, Langmuir Model, Leather, Low, Low Cost Adsorbent, Made, Mass Transfer, Mass Transfer Model, Mass-Transfer, Mb, Mechanism, Mechanisms, Methods, Methylene Blue, Model, Models, Order, Paper, Perlite, pH, Process, Pseudo Second Order, Pseudo Second Order Kinetic, Pseudo-First Order, Pseudo-First-Order, Pseudo-Second Order, Pseudo-Second Order Kinetic Model, Pseudo-Second-Order, Range, Rate, Redlich-Peterson, Redlich-Peterson Isotherm, Removal, Sorption, Temperature, Temperatures, Test, Textiles, Thermodynamic, Thermodynamic Parameters, Time, Transfer, Treatment, Wastewater, Water, Wheat, Wheat Bran

? Congeevaram, S., Dhanarani, S., Park, J., Dexilin, M. and Thamaraiselvi, K. (2007), Biosorption of chromium and nickel by heavy metal resistant fungal and bacterial isolates. Journal of Hazardous Materials, 146 (1-2), 270-277.

Full Text: 2007\J Haz Mat146, 270.pdf

Abstract: Microorganisms play a significant role in bioremediation of heavy metal contaminated soil and wastewater. In this study, heavy metal resistant fungi and bacteria were isolated from the soil samples of an electroplating industry, and the bioaccumulations of Cr(VI) and Ni(II) by these isolates were characterized to evaluate their applicability for heavy metal removal from industrial wastewaters. The optimum pH and temperature conditions for both the growth and heavy metal removal were determined for each isolate. The optimal pH for fungal isolates was lower (5–5.2) than that for bacterial isolates (7). The observed effect(s) of pH was attributable mainly to organism-specific physiology because in all the tested cases the cellular growth positively correlated with heavy metal removal. Batch and tolerance experiments provided information for solid retention time (SRT) design and the lethal tolerance limits for the isolated microorganisms. Experimental results indicated that expanded SRTs (stationary phase) can be recommended while using the fungal and bacterial Cr-resistant isolates for removing chromium. In the case of Ni-resistant bacterial isolate, a non-expanded SRT was recommended for designing continuous-flow completely stirred (CFCS) bioreactor so that a mid-log phase of cellular growth can be kept during the bioaccumulation process. The tolerance data with a high range of heavy metal concentrations revealed the Cr-resistant isolates, especially the fungal one, could tolerate chromium toxicity at up to 10,000 mg L⁻¹ chromium. Result indicates the applicability of the isolated Micrococcus sp. and Aspergillus sp. for the removal of chromium and nickel from industrial wastewater.

Keywords: Fungi, Bacteria, Bioaccumulation, Metal Bioremediation, pH, Temperature, Tolerance

? Mohan, S.V., Shailaja, S., Krishna, M.R. and Sarma, P.N. (2007), Adsorptive removal of phthalate ester (Di-ethyl phthalate) from aqueous phase by activated carbon: A kinetic study. Journal of Hazardous Materials, 146 (1-2), 278-282.

Full Text: 2007\J Haz Mat146, 278.pdf

Abstract: Adsorptive studies were carried out on Di-ethyl phthalate (DEP) removal from aqueous phase onto activated carbon. Batch sorption studies were performed and the results revealed that activated carbon demonstrated ability to adsorb DEP. Influence of varying experimental conditions such as DEP concentration, pH of aqueous solution, and dosage of adsorbent were investigated on the adsorption process. Sorption interaction of DEP onto activated carbon obeyed the pseudo second order rate equation. Experimental data showed good fit with both the Langmuir and Freundlich adsorption isotherm models. DEP sorption was found to be dependent on the aqueous phase pH and the uptake was observed to be greater at acidic pH.

Keywords: Activated Carbon, Adsorbent, Adsorption, Adsorption Isotherm, Adsorption Isotherm Models, Adsorption Process, Aqueous Phase, Aqueous Solution, Azo-Dye, Biosorption, Carbon, Color, Concentration, Di-Ethyl Phthalate, Dosage, Effluent, Experimental, Fluoride, Freundlich, Freundlich Adsorption Isotherm, HPLC, Interaction, Isotherm, Isotherm Models, Isothermal Models, Kinetic, Kinetic Models, Kinetic Study, Langmuir, Models, Order, pH, Phthalate, Process, Pseudo Second Order, Pseudo-Second-Order, Rate, Rate Equation, Removal, Second Order, Sorption, Sorption Studies, Uptake, Water

? Kandah, M.I. and Meunier, J.L. (2007), Removal of nickel ions from water by multi-walled carbon nanotubes. Journal of Hazardous Materials, 146 (1-2), 283-288.

Full Text: 2007\J Haz Mat146, 283.pdf

Abstract: Multi-walled carbon nanotubes (MWCNTs) were produced by chemical vapor decomposition using acetylene gas in the presence of Ferrocene catalyst at 800 °C, and then oxidized with concentrated nitric acid at 150 °C. Both (as-produced and oxidized) CNTs were characterized by TEM, Boehm titration, N₂-BET and cation exchange capacity techniques. The adsorption capacity for nickel ions from aqueous solutions increased significantly onto the surface of the oxidized CNTs compared to that on the as-produced CNTs. The effects of adsorption time, solution pH and initial nickel ions concentrations on the adsorption uptake of Ni²⁺ for both the as-produced and oxidized CNTs were investigated at room temperature. Both Langmuir and Freundlich isotherm models match the experimental data very well. According to the Langmuir model the maximum nickel ions adsorption uptake onto the as-produced and oxidized CNTs were determined as 18.083 and 49.261 mg/g, respectively. Our results showed that CNTs can be used as an effective Ni²⁺ adsorbent due to the high adsorption capacity as well as the short adsorption time needed to achieve equilibrium.

Keywords: Adsorption, Carbon Nanotubes, Nickel, Water Pollution

? Song, L.Y., Zhao, Y.C., Wang, G.J., Li, B., Niu, D.J. and Chai, X.L. (2007), Biomimetic fat cell (BFC) preparation and for lindane removal from aqueous solution. Journal of Hazardous Materials, 146 (1-2), 289-294.

Full Text: 2007\J Haz Mat146, 289.pdf

Abstract: Fat tissue of organism can accumulate hydrophobic chemicals efficiently and the accumulation level has a positive correlation with fat quantity. In this work, based on this characteristic, an innovative agent, that is, biomimetic fat cell (BFC) has been synthesized with interfacial polymerization. BFC has a hydrophobic nucleolus-triolein and hydrophilic membrane-polyamide, through which water, carrying hydrophobic organic contaminants (HOCs), can pass. This process is followed by the accumulation of HOCs. BFC has 97.39% lindane removal ability. This is close to 98.12% lindane removal by powder active carbon (PAC) in aqueous solution and 7 mg/L initial concentration of lindane. BFC can be regenerated easily by organic solvent dialysis in comparison with high temperature or pressure used for PAC regeneration. Lindane removal by BFC may occur through two mechanisms: bioaccumulation by BFC nucleolus-triolein; and adsorption by BFC membrane. Bioaccumulation is the prevailing mechanism.

Keywords: Biomimetic Fat Cell (BFC), Interface Polymerization, Bioaccumulation, Adsorption, Lindane

? Al-Ghouti, M.A., Khraisheh, M.A.M., Ahmad, M.N. and Allen, S.J. (2007), Microcolumn studies of dye adsorption onto manganese oxides modified diatomite. Journal of Hazardous Materials, 146 (1-2), 316-327.

Full Text: 2007\J Haz Mat146, 316.pdf

Abstract: The method described here cannot fully replace the analysis of large columns by small test columns (microcolumns). The procedure, however, is suitable for speeding up the determination of adsorption parameters of dye onto the adsorbent and for speeding up the initial screening of a large adsorbent collection that can be tedious if a several adsorbents and adsorption conditions must be tested. The performance of methylene blue (MB), a basic dye, Cibacron reactive black (RB) and Cibacron reactive yellow (RY) was predicted in this way and the influence of initial dye concentration and other adsorption conditions on the adsorption behaviour were demonstrated. On the basis of the experimental results, it can be concluded that the adsorption of RY onto manganese oxides modified diatomite (MOMD) exhibited a characteristic “S” shape and can be simulated effectively by the Thomas model. It is shown that the adsorption capacity increased as the initial dye concentration increased. The increase in the dye uptake capacity with the increase of the adsorbent mass in the column was due to the increase in the surface area of adsorbent, which provided more binding sites for the adsorption. It is shown that the use of high flow rates reduced the time that RY in the solution is in contact with the MOMD, thus allowing less time for adsorption to occur, leading to an early breakthrough of RY. A rapid decrease in the column adsorption capacity with an increase in particle size with an average 56% reduction in capacity resulting from an increase in the particle size from 106–250 μm to 250–500 μm. The experimental data correlated well with calculated data using the Thomas equation and the bed depth–service time (BDST) equation. Therefore, it might be concluded that the Thomas equation and the BDST equations can produce accurate predication for variation of dye concentration, mass of the adsorbent, flow rate and particle size. In general, the values of adsorption isotherm capacity obtained in a batch system show the maximum values and are considerably higher than those obtained in a fixed-bed.

Keywords: Diatomite, Modified Diatomite, Microcolumn, Reactive Dyes, Textile Effluent, Adsorption

? Günay, A., Arslankaya, E. and Tosun, İ. (2007), Lead removal from aqueous solution by natural and pretreated clinoptilolite: Adsorption equilibrium and kinetics. Journal of Hazardous Materials, 146 (1-2), 362-371.

Full Text: 2007\J Haz Mat146, 362.pdf

Abstract: Adsorption of Pb(II) ions from aqueous solution onto clinoptilolite has been investigated to evaluate the effects of contact time, initial concentration and pretreatment of clinoptilolite on the removal of Pb(II). Experimental data obtained from batch equilibrium tests have been analyzed by four two-parameter (Freundlich, Langmuir, Temkin and Dubinin–Radushkevich), four three-parameter (Redlich–Peterson, Sips, Toth and Khan) isotherm models, and kinetic models including the pseudo-first order, the pseudo-second order and Elovich equations using nonlinear regression technique. Of the two-parameter isotherms, Temkin isotherm was the best to describe the experimental data. Three-parameter isotherms have higher regression coefficients (>0.99) and lower relative errors (<5%) than two-parameter isotherms. The best fitting isotherm was the Sips followed by Toth and Redlich–Peterson isotherm equations. Maximum experimental adsorption capacity was found to be 80.933 and 122.400 mg/g for raw and pretreated clinoptilolite, respectively, for the initial concentration of 400 mg/L. Kinetic parameters; rate constants, equilibrium adsorption capacities and related coefficients for each kinetic model were evaluated according to relative errors and correlation coefficients. Results of the kinetic studies show that best fitted kinetic models are obtained to be in the order: the pseudo-first order, the pseudo-second order and Elovich equations. Using the thermodynamic equilibrium coefficients, Gibbs free energy of the Pb(II)–clinoptilolite system was evaluated. The negative value of change in Gibbs free energy (ΔG°) indicates that adsorption of Pb(II) on clinoptilolite is spontaneous.

Keywords: Activated Carbon, Adsorption, Adsorption Capacities, Adsorption Capacity, Ammonium Removal, Aqueous Solution, Batch, Batch Equilibrium, Batch-Equilibrium, Biosorption, Capacity, Clinoptilolite, Concentration, Constants, Contact Time, Correlation, Effects, Elovich, Energy, Equations, Equilibrium, Equilibrium Adsorption, Errors, Experimental, Experimental Data, Fitting, Free Energy, Freundlich, Gibbs Free Energy, Heavy-Metals, Ion-Exchange, Isotherm, Isotherm Models, Isotherms, Kinetic, Kinetic Model, Kinetic Models, Kinetic Studies, Kinetics, Langmuir, Lead, Model, Models, Natural, Nonlinear, Nonlinear Regression, Order, Packed-Bed, Parameters, Pb(II), Pb(II) Ions, Phanerochaete-Chrysosporium, Pretreated, Pretreatment, Pseudo Second Order, Pseudo-First Order, Pseudo-First-Order, Pseudo-Second Order, Pseudo-Second-Order, Rate, Rate Constants, Redlich-Peterson, Redlich-Peterson Isotherm, Regression, Removal, Sphagnum Moss Peat, Spontaneous, Temkin Isotherm, Tests, Thermodynamic, Thermodynamic Equilibrium, Time, Two-Parameter Isotherms, Waste-Water, Zeolite-Clinoptilolite

? Pamukoglu, M.Y. and Kargi, F. (2007), Mathematical modeling of copper(II) ion inhibition on COD removal in an activated sludge unit. Journal of Hazardous Materials, 146 (1-2), 372-377.

Full Text: 2007\J Haz Mat146, 372.pdf

Abstract: A mathematical model was developed to describe the Cu(II) ion inhibition on chemical oxygen demand (COD) removal from synthetic wastewater containing 15 mg l⁻¹ Cu(II) in an activated sludge unit. Experimental data obtained at different sludge ages (5–30 days) and hydraulic residence times (HRT) (5–25 h) were used to determine the kinetic, stoichiometric and inhibition constants for the COD removal rate in the presence and absence of Cu(II) ions. The inhibition pattern was identified as non-competitive, since Cu(II) ion inhibitions were observed both on maximum specific substrate removal rate (k) and on the saturation constant (K_s) with the inhibition constants of 97 and 18 mg l⁻¹, respectively, indicating more pronounced inhibition on K_s. The growth yield coefficient (Y) decreased and the death rate constant (b) increased in the presence of Cu(II) ions due to copper ion toxicity on microbial growth with inhibition constants of 29 and 200 mg l⁻¹, respectively indicating more effective inhibition on the growth yield coefficient or higher maintenance requirements. The mathematical model with the predetermined kinetic constants was able to predict the system performance reasonably well especially at high HRT operations.

Keywords: Activated Sludge, Biological Treatment, Copper(II) Ions, Inhibition, Mathematical Model

? Çiçek, F., Özer, D., Özer, A. and Özer, A. (2007), Low cost removal of reactive dyes using wheat bran. Journal of Hazardous Materials, 146 (1-2), 408-416.

Full Text: 2007\J Haz Mat146, 408.pdf

Abstract: In this study, the adsorption of Reactive Blue 19 (RB 19), Reactive Red 195 (RR 195) and Reactive Yellow 145 (RY 145) onto wheat bran, generated as a by-product material from flour factory, was studied with respect to initial pH, temperature, initial dye concentration, adsorbent concentration and adsorbent size. The adsorption of RB 19, RR 195 and RY 145 onto wheat bran increased with increasing temperature and initial dye concentration while the adsorbed RB 19, RR 195 and RY 145 amounts decreased with increasing initial pH and adsorbent concentration. The Langmuir and Freundlich isotherm models were applied to the experimental equilibrium data depending on temperature and the isotherm constants were determined by using linear regression analysis. The monolayer covarage capacities of wheat bran for RB 19, RR 195 and RY 145 dyes were obtained as 117.6, 119.1 and 196.1 mg/g at 60 °C, respectively. It was observed that the reactive dye adsorption capacity of wheat bran decreased in the order of RY 145 > RB 19 > RR 195. The pseudo-second order kinetic and Weber–Morris models were applied to the experimental data and it was found that both the surface adsorption as well as intraparticle diffusion contributed to the actual adsorption processes of RB 19, RR 195 and RY 145. Regression coefficients (R²) for the pseudo-second order kinetic model were higher than 0.99. Thermodynamic studies showed that the adsorption of RB 19, RR 195 and RY 145 dyes onto wheat bran was endothermic in nature.

Keywords: Activated Carbon, Adsorbent, Adsorbent Concentration, Adsorption, Adsorption, Adsorption Capacity, Analysis, Anionic Dyes, Aqueous-Solution, Bagasse-Fly-Ash, Biosorption, By-Product, Capacity, Concentration, Congo Red, Constants, Cost, Diffusion, Dye, Dye Adsorption, Dyes, Endothermic, Equilibrium, Equilibrium Data, Equilibrium Isotherm Analyses, Experimental, Experimental Data, Freundlich, Freundlich Isotherm, Intraparticle Diffusion, Isotherm, Isotherm Constants, Isotherm Models, Kinetic, Kinetic Model, Kinetic Models, Langmuir, Langmuir and Freundlich Isotherm, Linear, Linear Regression, Linked Chitosan Beads, Methylene-Blue, Model, Models, Monolayer, Order, pH, Pseudo Second Order, Pseudo Second Order Kinetic, Pseudo-Second Order, Pseudo-Second Order Kinetic Model, Pseudo-Second-Order, Reactive Blue 19 (RB 19), Reactive Dye, Reactive Dyes, Reactive Red 195 (RR 195) and Reactive Yellow 145 (RY 145), Regression, Regression Analysis, Removal, Size, Surface, Surface Adsorption, Temperature, Wheat, Wheat Bran

? Kumar, K.V., Porkodi, K. and Rocha, F. (2007), Comments on “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,