Personal Research Database

Full Text: 2007\J Haz Mat148, 387.pdf

Abstract: The adsorption characteristics of Cu(II) and Pb(II) onto expanded perlite (EP) from aqueous solution were investigated with respect to the changes in pH of solution. adsorbent dosage, contact time and temperature of solution. For the adsorption of both metal ions, the Langmuir isotherm model fitted to equilibrium data better than the Freundlich isotherm model. Using the Langmuir model equation, the monolayer adsorption capacity of EP was found to be 8.62 and 13.39 mg/g for Cu(II) and Pb(II) ions, respectively. Dubinin-Radushkevich (D-R) isotherm model was also applied to the equilibrium data and the mean free energies of adsorption were found as 10.82 kJ/mol for Cu(II) and 9.12 kJ/mol for Pb(II) indicating that the adsorption of both metal ions onto EP was taken place by chemical ion-exchange. Thermodynamic functions, the change of free energy (G). enthalpy (H) and entropy (S) of adsorption were also calculated for each metal ions. These parameters showed that the adsorption of Cu(II) and Pb(II) ions onto EP was feasible, spontaneous and exothermic at 20-50C. Experimental data were also evaluated in terms of kinetic characteristics of adsorption and it was found that adsorption process for both metal ions followed well pseudo-second-order kinetics. (c) 2007 Elsevier B.V. All rights reserved.

Keywords: Adsorbent, Adsorbent Dosage, Adsorption, Adsorption Capacity, Adsorption Characteristics, Adsorption Isotherm, Adsorption Process, Aqueous Solution, Bentonite, Capacity, Characteristics, Chemical, Contact Time, Copper(II), Cu(II), Dosage, Energy, Enthalpy, Entropy, Equilibrium, Equilibrium Data, Exothermic, Expanded Perlite, Free Energies, Free Energy, Freundlich, Freundlich Isotherm, G, Ion Exchange, Ion-Exchange, Isotherm, Isotherm Model, Kaolinite Clay, Kinetic, Kinetic Characteristics, Kinetics, Kinetics, Langmuir, Langmuir Isotherm, Langmuir Isotherm Model, Langmuir Model, Langmuir-Isotherm, Lead, Metal, Metal Ions, Metal-Ions, Model, Monolayer, Parameters, Pb(II), Pb(II) Ions, Perlite, pH, Process, Pseudo Second Order, Pseudo Second Order Kinetics, Pseudo-Second-Order, Pseudo-Second-Order Kinetics, Removal, Rice Husk Ash, Sorption, Spontaneous, Temperature, Thermodynamic Parameters, Thermodynamics, Time

? Yan, J.Y., Kirk, D.W., Jia, C.Q. and Liu, X.N. (2007), Sorption of aqueous phosphorus onto bituminous and lignitous coal ashes. Journal of Hazardous Materials, 148 (1-2), 395-401.

Full Text: 2007\J Haz Mat148, 395.pdf

Abstract: Aiming at the development of a phosphorus removal technology for waste water, phosphate (PO43-) retention behavior of bituminous and lignitous coal ashes was investigated using a batch reactor. Ash samples, including fresh and weathered fly and bottom ashes, were studied for their sorption isotherms and reversibility. Fly ashes had a much higher phosphate retention capacity (4000-30,000 mg P/kg) than bottom ashes (15-600 mg P/kg). Lignitous coal ashes were more capable of retaining phosphate than bituminous coal ashes. The retention process was largely irreversible. and the irreversibility increased with the increase in the retention capacity. Weathering enlarged the retention capacity of the bituminous bottom ash. but substantially lowered that of the fly ash, likely due to the difference in the weather-induced changes between the fly and bottom ashes. Sorption isotherms of fly ashes were found to be adequately represented by the Langmuir model while those of bottom ashes fitted better to the Freundlich model. Concentrations of Ca2+ and PO43- in the aqueous phase were measured at the end of sorption and desorption experiments, and were compared with solubilities of three calcium phosphate minerals. The aqueous solutions were saturated or super-saturated with respect to tricalcium phosphate (Ca-3(PO4)(3)) and hydroxyapatite (Ca-5 (PO4)(3)OH), and slightly under-saturated with respect to amorphous calcium phosphate. It is concluded that precipitation of calcium phosphate is the predominant mechanism for phosphate retention by coal ash under the conditions studied. There is a strong and positive correlation between alkalinity and phosphate sorption capacity. Consequently, acid neutralization capacity (ANC) can be used as an indicator of phosphate sorption capacity of coal ashes. (c) 2007 Elsevier B.V. All rights reserved.

Keywords: Bituminous and Lignitous Coal Ashes, Phosphorus Removal, Sorption Capacity and Mechanism, Speciation, Acid Neutralization Capacity, Combustion By-Products, Fly-Ash, Removal, Calcium, Water, Eutrophication, Solubility, Adsorption, Phosphate, Systems

? Farah, J.Y., El-Gendy, N.S. and Farahat, L.A. (2007), Biosorption of Astrazone Blue basic dye from an aqueous solution using dried biomass of Baker’s yeast. Journal of Hazardous Materials, 148 (1-2), 402-408.

Full Text: 2007\J Haz Mat148, 402.pdf

Abstract: In this study dried biomass of Baker’s yeast, Saccharomyces cerevisiae, is used as a sorbent for Astrazone Blue basic dye aqueous solution. Factors affecting the adsorption process: dye concentration, contact time, temperature and pH were investigated. The equilibrium concentration and the adsorption capacity at equilibrium were determined using three different sorption models namely: Langmuir, Freundlich and Temkin isotherms. It was found that increasing temperature and pH result in higher dye loadings per unit weight of the sorbent. The results gained from this study were described by Langmuir isotherm model better than Freundlich and Temkin isotherm models. The calculated heat of adsorption of the dye-yeast system indicates that the bio-sorption process is taking place by chemical adsorption and has an endothermic nature. The maximum adsorption capacity at 30C and pH 7 was calculated as 70mg/g for dried biomass of Baker’s yeast compared to 18.5 mg/g for commercial granular activated carbon, indicating that dried biomass of Baker’s yeast can be considered as a good sorbent material for Astrazone Blue solution. (c) 2007 Elsevier B.V. All rights reserved.

Keywords: Biosorption, Astrazone Blue, Basic Dye, Baker’s Yeast, Isotherm Models, Error Analysis, Saccharomyces-Cerevisiae, Fungal Biomass, Waste-Water, Removal, Adsorption, Ions, Sorption, Mechanism, Kinetics, Recovery

? Mounir, B., Pons, M.N., Zahraa, O., Yaacoubi, A. and Benhammou, A. (2007), Discoloration of a red cationic dye by supported TiO₂ photocatalysis. Journal of Hazardous Materials, 148 (3), 513-520.

Full Text: 2007\J Haz Mat148, 513.pdf

Abstract: The degradation under UV, visible and sunlight irradiation of C.I. Basic Red 46 (BR 46) dye used for acrylic fibers dyeing has been studied in a lab-scale continuous system with two different immobilized TiO₂ systems. Catalyst I was based on TiO₂ particles deposited on cellulose fibers; Catalyst 11 combined TiO₂ particles deposited on a layer of cellulose fibers (as in Catalyst 1) with a layer of carbon fibers and finally a layer of cellulose fibers. The treatment of aqueous dye solutions and industrial wastewater contaminated with the same dye has been evaluated in terms of color removal and chemical oxygen demand (COD) decrease. With UV light, aqueous solutions containing dye were decolorized slightly more rapidly with Catalyst II than with Catalyst I. Sunlight was also very effective and experiments involving sunlight irradiation showed Catalyst 11 to be the more efficient, giving more than 90% discoloration after 20 min of treatment. Comparing the discoloration yield by adsorption or under visible light for both catalysts, it was observed that the difference between them is below 5%. The adsorption kinetics was found to follow a second-order rate law for Catalyst I and a first-order bate law for Catalyst II. The kinetics of photocatalytic degradation under UV or sunlight were found to follow a first-order rate law for both catalytic systems. Under sunlight the COD removal yield for textile wastewater reaches 33% with Catalyst I against 93% with Catalyst II. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Acrylic Fibers, Activated Carbon, Activated-Sludge Process, Adsorbents, Adsorption, Adsorption Kinetics, Aqueous Solutions, Azo Dyes, Br, Carbon, Carbon Fibers, Catalysts, Catalytic, Cationic, Cationic Dye, Cellulose, Chemical, Chemical Oxygen Demand, COD, Cod Removal, Color, Color Removal, Continuous System, Degradation, Demand, Discoloration, Dye, Dye Solutions, Dyeing, Effective, Experiments, Fibers, First Order, Immobilized, Immobilized TiO₂, Industrial, Industrial Wastewater, Irradiation, Kinetics, Law, Light, Methylene-Blue, Oxygen, Oxygen Demand, Particles, Photocatalysis, Photocatalytic, Photocatalytic Degradation, Rate, Reactive Dyes, Removal, Second Order, Solutions, Sunlight, Supported TiO₂, Textile, Textile Effluents, Textile Wastewater, TiO₂, TiO₂ Photocatalysis, Titanium Dioxide, Treatment, UV, UV Light, UV Radiation, Visible Light, Visible-Light, Waste-Water, Wastewater, Yield

? Papandreou, A., Stournaras, C.J. and Panias, D. (2007), Copper and cadmium adsorption on pellets made from fired coal fly ash. Journal of Hazardous Materials, 148 (3), 538-547.

Full Text: 2007\J Haz Mat148, 538.pdf

Abstract: Studies on the utilization of low cost adsorbents for removal of heavy metals from wastewaters are gaining attention. Fired coal fly ash, a solid by-product that is produced in power plants worldwide in million of tonnes, has attracted researchers’ interest. In this work, fly ash was shaped into pellets that have diameter in-between 3-8 mm, high relative porosity and very good mechanical strength. The pellets were used in adsorption experiments for the removal of copper and cadmium ions from aqueous solutions. The effect of agitation rate, equilibration time, pH of solution and initial metal concentration were studied. The adsorption of both cations follows pseudo-second order kinetics reaching equilibrium after an equilibration time of 72 h. The experimental results for copper and cadmium adsorption fit well to a Langmuirian type isotherm. The calculated adsorption capacities of pellets for copper and cadmium were 20.92 and 18.98 mg/g, respectively. Desorption experiments were performed in several extraction media. The results showed that both metals were desorbed substantially from pellets under acidic solutions. For this reason, metal saturated pellets were encapsulated in concrete blocks synthesized from cement and raw pulverized fly ash in order to avoid metal desorption. The heavy metals immobilization after encapsulation in concrete blocks was tested through desorption tests in several aqueous media. The results showed that after 2 months in acidic media with pH 2.88 and 4.98 neither copper nor cadmium were desorbed thus indicating excellent stabilization of heavy metals in the concrete matrix. As a conclusion, the results showed that fly ash shaped into pellets could be considered as a potential adsorbent for the removal of copper and cadmium from wastewaters. Moreover, the paper proposes an efficient and simple stabilization process of the utilized adsorbents thus guarantying their safe disposal in industrial landfills and eliminating the risk of pollution for groundwater and other natural water receivers. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Acidic Media, Adsorbent, Adsorbents, Adsorption, Adsorption Capacities, Adsorption Isotherms, Agitation, Aqueous Solutions, Aqueous-Solutions, Ash, Attention, By-Product, Cadmium, Cadmium Adsorption, Cadmium Ions, Cations, Cement, Coal, Coal Fly Ash, Concentration, Concrete, Copper, Copper and Cadmium Removal Kinetics, Cost, Desorption, Diameter, Disposal, Encapsulated, Encapsulation, Equilibrium, Experimental, Experiments, Extraction, Fly Ash, Fly-Ash, Geopolymers, Groundwater, Heavy Metals, Heavy-Metals, Immobilization, Industrial, Ions, Isotherm, Kinetics, Landfills, Low, Low Cost Adsorbents, Low-Cost Adsorbents, Made, Matrix, Mechanical, Mechanical Strength, Media, Metal, Metal Desorption, Metals, Natural, Natural Water, Order, Paper, Pellets, pH, Plants, Pollution, Porosity, Potential, Power Plants, Process, Pseudo Second Order, Pseudo Second Order Kinetics, Pseudo-Second Order, Pseudo-Second Order Kinetics, Pseudo-Second-Order, Rate, Removal, Removal of Heavy Metals, Risk, Solutions, Sorbents, Sorption, Stabilization, Strength, Tests, Time, Utilization, Waste, Wastewaters, Water

? Mohapatra, M. and Anand, S. (2007), Studies on sorption of Cd(II) on Tata chromite mine overburden. Journal of Hazardous Materials, 148 (3), 553-559.

Full Text: 2007\J Haz Mat148, 553.pdf

Abstract: Chromite mine overburden containing iron as oxide/hydroxide, a waste material generated in chromite mines was used as sorbent for cadmium. The iron content of material was 43.75% with a specific surface area of 50.8 m²/g. Batch experiments were conducted to study the sorption behavior of Cd(II) on this material. The variable experimental parameters were: time, pH, temperature, Cd(II) and sample concentration. The point of zero charge (PZC) of the overburden sample was experimentally determined as 6.48 which shifted to a pH of 7.8 when the sample was equilibrated with 100 mg/L Cd(II) solution. Maximum loading capacity of the overburden sample was found to be similar to 19 mg Cd/g of material. It was observed that within 30 min the sorption attains equilibrium. Hence, the sorption data generated at 30 min with various initial Cd(II) concentrations and temperatures were taken to evaluate the thermodynamic parameters, i.e., G, H and S. The G values reflect the feasibility of the metal removal from aqueous solution. The negative values of H confirmed the exothermic sorption of cadmium and the positive S values suggested the increased randomness at the solid-solution interface. The sorption data fitted well to both the Langmuir and Freundlich isotherm models indicating a monolayer sorption. The value of Freundlich parameter V (n is indicative of sorption intensity) lying between 1.46 and 1.59 shows that the surface of the sorbent is heterogeneous in nature. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Chromite Mine Overburden, Cadmium, Thermodynamics, Langmuir Isotherm, Freundlich Isotherm, Aqueous-Solutions, Cadmium Ions, Fly-Ash, Adsorption, Removal, Biosorption, Goethite, Cr(VI), Copper, Water

? Gunay, A. (2007), Application of nonlinear regression analysis for ammonium exchange by natural (Bigadiç) clinoptilolite. Journal of Hazardous Materials, 148 (3), 708-713.

Full Text: 2007\J Haz Mat148, 708.pdf

Abstract: The experimental data of ammonium exchange by natural Bigadic clinoptilolite was evaluated using nonlinear regression analysis. Three two-parameters isotherm models (Langmuir, Freundlich and Temkin) and three three-parameters isotherm models (Redlich-Peterson, Sips and Khan) were used to analyse the equilibrium data. Fitting of isotherm models was determined using values of standard normalization error procedure (SNE) and coefficient of determination (R-2). HYBRID error function provided lowest sum of normalized error and Khan model had better performance for modeling the equilibrium data. Thermodynamic investigation indicated that ammonium removal by clinoptilolite was favorable at lower temperatures and exothermic in nature. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Ammonium, Ammonium Exchange, Ammonium Removal, Analysis, Aqueous-Solution, Clinoptilolite, Coefficient of Determination, Determination, Equilibrium, Equilibrium Data, Error Function, Exothermic, Experimental, Experimental Data, Freundlich, Function, Hybrid, Investigation, Ion Adsorption, Isotherm, Isotherm Models, Kinetics, Langmuir, Model, Modeling, Models, Natural, Nonlinear, Nonlinear Regression, Performance, Redlich-Peterson, Regression, Regression Analysis, Removal, Sepiolite, Sorption, Standard, Temperatures, Thermodynamic, Water, Zeolite

? Önal, Y., Akmil-Başar, Ç. and Sarıcı-Özdemir, C. (2007), Elucidation of the naproxen sodium adsorption onto activated carbon prepared from waste apricot: Kinetic, equilibrium and thermodynamic characterization. Journal of Hazardous Materials, 148 (3), 727-734.

Full Text: 2007\J Haz Mat148, 727.pdf

Abstract: In this study, activated carbon (WA11Zn5) was prepared from waste apricot, which is waste in apricot plants in Malatya, by chemical activation with ZnCl₂. BET surface area of activated carbon is determined as 1060 m²/g. The ability of WA11Zn5, to remove naproxen sodium from effluent solutions by adsorption has been studied. Equilibrium isotherms for the adsorption of naproxen sodium on activated carbon were measured experimentally. Results were analyzed by the Langmiur, Freundlich equation using linearized correlation coefficient at 298 K. The characteristic parameters for each isotherm have been determined. Langmiur equation is found to best represent the equilibrium data for naproxen sodium-WA11Zn5 systems. The monolayer adsorption capacity of WA11Zn5 for naproxen sodium was found to be 106.38 mg/g at 298 K. The process was favorable and spontaneous. The kinetics of adsorption of naproxen sodium have been discussed using three kinetic models, i.e., the pseudo first-order model, the pseudo second-order model, the intraparticle diffusion model. Kinetic parameters and correlation coefficients were determined. It was shown that the pseudo second-order kinetic equation could describe the adsorption kinetics for naproxen sodium onto WA11Zn5. The thermodynamic parameters, such as G, S and H, were calculated. The thermodynamics of naproxen sodium-WA11Zn5 system indicates endothermic process. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: 298 K, 298-K, Acid Dyes, Activated Carbon, Activation, Adsorbents, Adsorption, Adsorption Capacity, Adsorption Kinetics, Aqueous-Solution, Behavior, BET, BET Surface Area, Binding, Capacity, Carbon, Characteristic, Characterization, Chemical, Chemical Activation, Congo Red, Correlation, Diffusion, Diffusion Model, Effluent, Endothermic, Equilibrium, Equilibrium Data, First Order, Freundlich, Freundlich Equation, G, Intraparticle, Intraparticle Diffusion, Intraparticle Diffusion Model, Isotherm, Isotherms, Kinetic, Kinetic Equation, Kinetic Models, Kinetics, Kinetics of Adsorption, Model, Models, Monolayer, Monolayer Adsorption, Naproxen, Naproxen Sodium, Parameters, Plants, Process, Pseudo First-Order, Pseudo Second Order, Pseudo Second Order Kinetic, Pseudo Second-Order, Pseudo Second-Order Model, Pseudo-First-Order, Pseudo-Second-Order, Reaction Kinetics, Removal, Sawdust, Second Order, Sodium, Solutions, Sorption, Spontaneous, Surface, Surface Area, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Waste, Water, ZnCl₂

? Sayilkan, F., Asiltürk, M., Tatar, P., Kiraz, N., Arpat, E. and Sayilkan, H. (2007), Preparation of re-usable photocatalytic filter for degradation of Malachite Green dye under UV and vis-irradiation. Journal of Hazardous Materials, 148 (3), 735-744.

Full Text: 2007\J Haz Mat148, 735.pdf

Abstract: Sn⁴⁺ doped and undoped nano-TiO₂ particles easily dispersed in water were synthesized without using organic solvent by hydrothermal process. Nanostructure-TiO₂ based thin films were prepared on flyswatter substrate, made with stainless steel, by dip-coating technique. The structure, surface and optical properties of the particles and thin films were characterized by element analysis and XRD, BET, SEM and UV, vis, NIR techniques. The photocatalytic performance of the films were tested for degradation of Malachite Green dye in solution under UV and vis-lights. The results showed that the coated flyswatter has a very high photocatalytic performance for the photodegradation of Malachite Green irradiated with UV and vis-lights. The results also proved that the hydrothermally synthesized nano-TiO₂ particles are fully anatase crystalline form and are easily dispersed in water, the coated surfaces are hydrophilic, and the doping of transition metal ion efficiently improved the degradation performance of TiO₂-coated flyswatter. The photocatalytic performances determined at both irradiation conditions were very good and were almost similar to each other for Sn⁴⁺ doped TiO₂-coated flyswatter and it can be repeatedly used with increasing photocatalytic activity compared to undoped TiO₂-coated flyswatter.

Keywords: Analysis, Anatase, BET, Coated, Degradation, Dye, Hydrothermal Process, Irradiation, Malachite Green, Malachite-Green, Metal, Nano-TiO₂, Optical Properties, Organic, Particles, Performance, Photocatalysis, Photocatalytic, Photocatalytic Activity, Photodegradation, SEM, Sn-Doping, Solution, Structure, Surface, Surfaces, Techniques, Thin Film, UV, Water, XRD

? Lee, C.K., Liu, S.S., Juang, L.C., Wang, C.C., Lyu, M.D. and Hung, S.H. (2007), Application of titanate nanotubes for dyes adsorptive removal from aqueous solution. Journal of Hazardous Materials, 148 (3), 756-760.

Full Text: 2007\J Haz Mat148, 756.pdf

Abstract: The potential of adsorptive removal of basic dyes with titanate nanotubes (TNTs) and acid dyes with surfactant (hexadecyltrimethylammonium (HDTMA) chloride)-modified TNTs were investigated. TNTs were prepared via a hydrothermal method and subsequently washed with HCl aqueous solutions of different concentrations. The prepared TNTs were then mediated by the HDTMA ions through the cation exchange process. Effects of acid washing and HDTMA-modified process on the revolution of microstructure and surface chemistry characteristics of TNTs were characterized with XRD, nitrogen adsorption-desorption isotherms, and FTIR. The adsorption capacities of two basic dyes (two acid dyes) on TNTs (their HDTMA-modified version) at initial dye concentration of 2000 mg/L were measured. It was experimentally concluded that if the amount of Na+ in the TNTs was not very low, the TNTs and their HDTMA-modified version might be a good adsorbent for the removal of basic and acid dyes from aqueous solution through the cation and anion exchange mechanism, respectively. The adsorption capacity for basic and acid dyes could reach 380 and 400 mg/g, respectively. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Acid Washing, Adsorption, Basic Dyes, Cation Exchange, Dye, Dyes, Low-Cost Adsorbents, Surfactant, Titanate Nanotubes

? Çelebi, O., Üzüm, Ç., Shahwan, T. and Erten, H.N. (2007), A radiotracer study of the adsorption behavior of aqueous Ba²⁺ ions on nanoparticles of zero-valent iron. Journal of Hazardous Materials, 148 (3), 761-767.

Full Text: 2007\J Haz Mat148, 761.pdf

Abstract: Recently, iron nanoparticles are increasingly being tested as adsorbents for various types of organic and inorganic pollutants. In this study, nanoparticles of zero-valent iron (NZVI) synthesized under atmospheric conditions were employed for the removal of Ba²⁺ ions in a concentration range 10^-3 to 10^-6 M. Throughout the study, Ba-133 was used as a tracer to study the effects of time, concentration, and temperature. The obtained data was analyzed using various kinetic models and adsorption isotherms. Pseudo-second-order kinetics and Dubinin-Radushkevich isotherm model provided the best correlation with the obtained data. Observed thermodynamic parameters showed that the process is exothermic and hence enthalpy-driven. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Adsorbents, Adsorption, Adsorption Behavior, Adsorption Isotherms, Barium, Behavior, Concentration, Contaminants, Correlation, Dubinin-Radushkevich Isotherm, Effects, Electrochemistry, Exothermic, Groundwater, Inorganic, Ions, Iron, Isotherm, Isotherm Model, Isotherms, Kinetic, Kinetic Models, Kinetics, Model, Models, Nano-Zero-Valent Iron, Nanoparticles, Organic, Parameters, Pollutants, Process, Radiotracer, Range, Remediation, Removal, Sequestration, Sorption, Spectroscopy, Temperature, Thermodynamic, Thermodynamic Parameters, Time, Tracer, Zero-Valent, Zero-Valent Iron, Zerovalent Iron

? Fu, L., Huang, X.H. and Wang, H.Y. (2007), Comment on “Removal of supranol Yellow 4GL by adsorption onto Cr-intercalated montmorillonite”. Journal of Hazardous Materials,