Personal Research Database

Full Text: 2009\J Haz Mat165, 623.pdf

Abstract: The viability of some heavy ions removal from phosphoric acid solution by means of impregnated charcoal with triphenylphosphine sulphide extractant has been demonstrated in this work. Factors affecting removal of Cu²⁺, Cd²⁺, Zn²⁺ and Pb²⁺ include initial concentration of ions, Volume of the aqueous Solution to weight of adsorbent ratio (V/m), concentration of the extractant loaded onto charcoal and temperature. The removal percent of these ions is increased by decreasing values of V/m ratio and increasing temperature for all ions. The sorption isotherms data fit Langmuir, Freundlich and Dubinin-Radushkviech (D-R) models. The Values of the mean free energy, E, of sorption is in all cases in the range 9.1-25.6 KJ/mol, which are within the ranges of chemical sorption reaction. The sorption reaction was found to obey a pseudo second-order rate model. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Cd(II), Heavy Metals, Impregnated Charcoal, Langmuir, Models, Phosphoric Acid, Removal, Resins, Sorption, Triphenylphosphine Sulphide

? Ada, K., Ergene, A., Tan, S. and Yaçın, E. (2009), Adsorption of Remazol Brilliant Blue R using ZnO fine powder: Equilibrium, kinetic and thermodynamic modeling studies. Journal of Hazardous Materials, 165 (1-3), 637-644.

Full Text: 2009\J Haz Mat165, 637.pdf

Abstract: Zinc oxide powders with six-sided flake-like particles were prepared by homogeneous precipitation from boiling aqueous solutions that contained excess urea and 0.075 (Z075) and 0.300 (Z300) M Zn(2+). The average sizes of the particles are 37 and 46 mu m, while the average sizes of the crystals are similar to 45 for Z075 and Z300 at 1000 degrees C. Equilibrium, kinetic and thermodynamic studies were carried out for the adsorption of RBBR dye from aqueous solution using both types of ZnO in the form of fine powders. The effects of pH, initial dye concentration, contact time and temperature of solution on the adsorption were studied. Langmuir, Temkin and Dubinin-Radushkevich (D-R) isotherm models were used to describe the adsorption of RBBR onto ZnO powders. The Langmuir and D-R isotherm models fit the equilibrium data better than the Temkin isotherm model. The monomolecular adsorption capacity of Z075 and Z300 was determined to be 190 and 345 mg g(-1) for RBBR, respectively. The Lagergren first-order, Ritchie second-order kinetic and intra-particle diffusion models were used for the adsorption of the dye onto ZnO powders. The Ritchie second-order model was suitable for describing the adsorption kinetics for the removal of RBBR front aqueous solution onto Z075 and Z300. Thermodynamic parameters, such as the Gibbs free energy (Delta G(#)), enthalpy (Delta H(#)), entropy (Delta S(#)) and equilibrium constant of activation (K(#)) were calculated. These parameters showed that the adsorption process of RBBR onto Z075 and Z300 was an endothermic process of a chemical nature under the studied conditions. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Carbons, Activation, Adsorption, Adsorption Kinetics, Aqueous-Solutions, Biosorption, Capacity, Diffusion, DR Isotherm, Emulsion Evaporation, Energy, Equilibrium, First Order, Fly-Ash, G Reactive Dye, Gibbs Free Energy, Intraparticle Diffusion, Isotherm, Isotherm Models, Isotherms, Kinetic, Kinetics, Langmuir, Model, Modeling, pH, Precipitation, Remazol Brilliant Blue R, Removal, Sorption, Surface, Textile Effluent, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Zinc, Zinc Oxide Powders, Zinc-Oxide Powder, Zn²⁺

? Zhu, M.X., Ding, K.Y., Xu, S.H. and Jiang, X. (2009), Adsorption of phosphate on hydroxyaluminum- and hydroxyiron-montmorillonite complexes. Journal of Hazardous Materials, 165 (1-3), 645-651.

Full Text: 2009\J Haz Mat165, 645.pdf

Abstract: One hydroxyaluminum-montmorillonite complex (HyAl-Mt), two hydroxyiron-montmorillonite complexes (HyFe-Mts) with different iron contents, and three hydroxyiron/aluminum-montmorillonite complexes (HyFeAl-Mts) with various Fe:AI molar ratios were synthesized. Behavior and kinetics of phosphate (P) sorption on selected Mt-complexes mentioned above were investigated under acidic conditions. The results indicated that the intercalations of polymeric HyFe and/or HyAl ions in interlayers of Na- saturated montmorillonite (Na-Mt) caused significant changes in surface properties of the Na-Mt, Such as cation exchange capacity, specific surface area, pH at zero point of charge. In pH range tested (3.0-6.5), P adsorption on the Mt-complexes decreased with increasing pH, whereas the effect became weaker with increasing Fe contents in the Mt-complexes. The adsorption capacities of the HyFeAl-Mts were greater than those of the HyAl-Mt and HyFe-Mt, which could be attributed to decreasing crystallinity of Fe and Al oxides in the HyFeAl-Mts. The equilibrium adsorption of P on the Mt-complexes could be well described using the Langmuir isotherm, and the kinetics of P adsorption could be well described by both the pseudo-second-order and Elovich models. An increase in Fe contents in the Mt-complexes could enhance the initial kinetic rate of P adsorption, as suggested by the Elovich models. it is inferred that a great number of Fe-related active sorption sites have been located oil the outer surfaces of the HyFe-Mt, as indicated by extremely high alpha value in the Elovich model. Previous studies focusing mainly oil P sorption on HyAl-Mt complexes might have underestimated the contributions of Mt-complexes to P retention in acidic soils high in Fe contents. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Adsorbents, Adsorption, Al, Aluminum-Iron, Behavior, Binary Oxide Suspensions, Desorption, Fe, Ferrihydrite, Hydroxyaluminum, Hydroxyiron, Langmuir, Montmorillonite, pH, Phosphate, Soils, Surface

? Chang, Y.C. and Chen, D.H. (2009), Catalytic reduction of 4-nitrophenol by magnetically recoverable Au nanocatalyst. Journal of Hazardous Materials, 165 (1-3), 664-669.

Full Text: 2009\J Haz Mat165, 664.pdf

Abstract: A novel magnetically recoverable Au nanocatalyst was fabricated by the simple adsorption-reduction of Au(III) ions on chitosan-coated iron oxide magnetic nanocarrier. Au nanoparticles with a mean diameter of 3.14 non were well loaded on the surface of magnetic nanocarrier because chitosan layer provided an effective driving force in the formation and stabilization of Au nanoparticles. The resultant magnetically recoverable Au nanocatalyst exhibited excellent catalytic activity to the reduction of 4-nitrophenol (4-NP) with sodium borohydride. The rate constants evaluated in terms of pseudo-first-order kinetic model increased with increasing the amount of Au nanocatalyst, decreasing the initial 4-NP concentration, and increasing the temperature. Also, the kinetic data suggested that this catalytic reaction was diffusion controlled owing to the presence of chitosan layer. In addition, catalyst reuse showed no trace of deactivation or poisoning during the catalytic and separation processes, revealing the stable nature and good catalytic ability of this nanocatalyst. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: 4-Nitrophenol, Adsorption, Aqueous-Solution, Aromatic Nitro-Compounds, Catalytic Reduction, Chitosan, Chitosan Nanocomposites, Cu(II) Ions, Diffusion, Driving, Gold, Gold Nanoparticles, Ions, Iron, Iron Oxide, Kinetic, Kinetic Model, Magnetic Recoverable Catalyst, Metal-Ions, Model, Nano-Adsorbent, Nitrophenol, P-Nitrophenol, Pseudo-First-Order, Reduction, Reuse, Silver

? Bhainsa, K.C. and D’Souza, S.F. (2009), Thorium biosorption by Aspergillus fumigatus, a filamentous fungal biomass. Journal of Hazardous Materials, 165 (1-3), 670-676.

Full Text: 2009\J Haz Mat165, 670.pdf

Abstract: Thorium biosorption by Aspergillus fumigatus was carried out in a batch reactor to study the effect of initial pH and metal ion concentration, contact time, biomass dose and kinetics and equilibrium Th uptake. Thorium(IV) uptake by A. fumigatus was pH dependent (pH range, 2.0-6.0) and maximum sorption was observed at pH 4.0. The uptake was rapid and the biosorption process reached equilibrium within 2 h of contact times at pH 2-4 and initial Th concentration of 50 and 100 mg/L. The kinetics data fitted well to Lagergren’s pseudo-second-order rate equation (r(2) > 0.99). A maximum initial sorption rate of 71.94 (mg/g min) and second-order rate constant of 7.8210^-2 (g/mg min) were observed at pH 4.0,50 mg Th/L. The observed maximum uptake of thorium was 370 mg Th/g at equilibrium. Biosorption process could be well described by Langmuir isotherm in comparison to Freundlich and Temkin isotherms. Sodium bicarbonate was the most efficient desorbing reagent with desorption efficiency of more than 99%. Environmental scanning electron micrograph (ESEM) showed that the surface of the biomass after desorption was intact. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Aqueous-Solution, Aspergillus Fumigatus, Biosorbent, Biosorption, Copper Ions, Desorption, Esem, Heavy-Metals, Isotherm, Langmuir, Pb(II), pH, Removal, Thorium, Uranium(VI)

? You, S.J., Tsai, Y.P. and Huang, R.Y. (2009), Effect of heavy metals on nitrification performance in different activated sludge processes. Journal of Hazardous Materials, 165 (1-3), 987-994.

Full Text: 2009\J Haz Mat165, 987.pdf

Abstract: To understand the toxic effect of heavy metals on the nitrification mechanisms of activated Sludge, this study identified the specific ammonia utilization rate (SAUR) inhibited by Pb, Ni and/or Cd shock loadings. Seven different heavy metal combinations (Pb, Ni, Cd, Pb + Ni, Ni + Cd, Pb + Cd, and Pb + Ni + Cd) wit It seven different heavy metal concentrations (0, 2. 5, 10, 15, 25, and 40 ppm, respectively) were examined by batch experiments, where the activated sludge was taken from either sequencing batch reactor (SBR) or anaerobic-anoxic-oxic (A(2)O) processes. The experimental results showed the SAUR inhibition rate was Ni > Cd > Pb. No significant inhibition in the nitrification reaction of the activated sludge was observed even when as Much as 40 ppm Pb was added. In addition, no synergistic effect was found when different heavy metals were simultaneously added in different concentrations, and the overall inhibition effect depended on the heavy metal with the highest toxicity. Further, first order kinetic reaction could model the behavior of SAUR inhibition on activated sludge when adding heavy metals, and the SAUR inhibition formula was derived as SAUR = (SAUR(max) - SAUR(min)) x e(-ric) + SAUR(min). On the other hand, the heavy metal adsorption ability in both the activated sludge system was Pb = Cd > Ni. The specific adsorption capacity of activated sludge on heavy metal increased as the heavy metal concentration increased or the mixed liquid volatile Suspended solid (MLVSS) decreased. The batch experiments also showed the heavy metal adsorption capacity of the SBR sludge was larger than the A(2)O sludge. Finally, the most predominant bacteria in the phylogenetic trees of SBR and A(2)O activated sludges were proteobacteria, which contributed to 42.1% and 42.8% of the total clones. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Sludge, Adsorption, Bacteria, Batch, Behavior, Biomass, Cadmium, Cadmium Speciation, Capacity, Experimental, First Order, Hand, Heavy Metal, Heavy Metals, Inhibition, Kinetic, Lead, Mechanisms, Metal, Metals, Model, Nickel, Nitrification, Reactors, Sequencing Batch Reactor, Sludge, Toxicity, Utilization

? Altenor, S., Carene, B., Emmanuel, E., Lambert, J., Ehrhardt, J.J. and Gaspard, S. (2009), Adsorption studies of methylene blue and phenol onto vetiver roots activated carbon prepared by chemical activation. Journal of Hazardous Materials, 165 (1-3), 1029-1039.

Full Text: 2009\J Haz Mat165, 1029.pdf

Abstract: Vetiver roots have been utilized for the preparation of activated carbon (AC) by chemical activation with different impregnation ratios of phosphoric acid, X-p (gH₃PO₄/g precursor): 0.5:1; 1:1 and 1.5:1. Textural characterization, determined by nitrogen adsorption at 77 K shows that mixed microporous and mesoporous structures activated carbons (ACs) with high surface area (>1000 m²/g) and high pore volume (Lip to 1.19cm³/g) can be obtained. The surface chemical properties of these ACs were investigated by X-ray photoelectron spectroscopy (XPS) and Boehm titration. Their textural and chemical characteristics were compared to those of an AC sample obtained by steam activation of vetiver roots. Classical molecules used for characterizing liquid phase adsorption, phenol and methylene blue (MB), were used. Adsorption kinetics of MB and phenol have been studied using commonly used kinetic models, i.e., the pseudo-first-order model, the pseudo-second-order model, the intraparticle diffusion model and as well the fractal, BWS (Brouers, Weron and Sotolongo) kinetic equation. The correlation coefficients (RI) and the normalized standard deviation Delta q (%) were determined showing globally, that the recently derived fractal kinetic equation Could best describe the adsorption kinetics for the adsorbates tested here, indicating a complex adsorption mechanism. The experimental adsorption isotherms of these molecules on the activated carbon were as well analysed using four isotherms: the classical Freundlich, Langmuir, Redlich-Peterson equations, but as well the newly published deformed Weibull Brouers-Sotolongo isotherm. The results obtained from the application of the equations show that the best fits were achieved with the Brouers-Sotolongo equation and with the Redlich-Peterson equation. Influence of surface functional groups towards MB adsorption is as well Studied using various ACs prepared from vetiver roots and sugar cane bagasse. Opposite effects governing MB and phenol adsorption mechanism on ACs are demonstrated. The various effects involved in adsorption mechanisms of each molecule are demonstrated. (C) 2008 Published by Elsevier B.V.

Keywords: Activated Carbon, Adsorption, Adsorption Properties, Aqueous-Solutions, Bagasse, Characterization, Coffee Grounds, Equilibrium, Fractal Kinetic, Functional Groups, H₃PO₄, Isotherm, Langmuir, Methylene Blue, Optimization, Parameters, Phenol, Phosphoric-Acid Activation, Stones, Surface-Area, Texture, Vetiver Roots, Water-Treatment

? Lu, Y., Yan, L.H., Wang, Y., Zhou, S.F., Fu, J.J. and Zhang, J.F. (2009), Biodegradation of phenolic compounds from coking wastewater by immobilized white rot fungus Phanerochaete chrysosporium. Journal of Hazardous Materials, 165 (1-3), 1091-1097.

Full Text: 2009\J Haz Mat165, 1091.pdf

Abstract: A white rot fungus Phanerochaete chrysosporium, immobilized with the wood chips of Italian poplar, was employed for biodegradation of phenolic compounds in coking wastewater. The immobilized fungus, dried by vacuum freeze desiccator. was kept high activity after a 9-month preservation and easy to be activated and domesticated. The removal rates of phenolic compounds and COD by immobilized fungus were 87.05% and 72.09% in 6 days, which were obviously higher than that by free fungus. For phenolic compounds biodegradation, a pH ranging from 4.0 to 6.0 and a temperature ranging from 28 C to 37 degrees C create suitable conditions, and optimum 5.0 and 35 degrees C. respectively. The optimum removal rate of phenolic compounds was over 84% and COD was 80% in 3 days. And the biodegradation of phenolic compounds followed the first-order kinetics. It is an efficient and convenient method for coking wastewater treatment. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Biodegradation, Biosorption, Chlorophenols, COD, Coking Wastewater, Decolorization, Degradation, First Order, Immobilized, Kinetics, Laccase Production, Pentachlorophenol, Peroxidase, pH, Phanerochaete Chrysosporium, Phenolic Compounds, Removal, Synthetic Dyes, Trametes-Versicolor, Treatment, Wastewater, Wastewater Treatment, White Rot Fungus, Wood Chip

? Doğan, M., Karaoğlu, M.H. and Alkan, M. (2009), Adsorption kinetics of maxilon yellow 4GL and maxilon red GRL dyes on kaolinite. Journal of Hazardous Materials, 165 (1-3), 1142-1151.

Full Text: 2009\J Haz Mat165, 1142.pdf

Abstract: Kaolinite, a low-costly material, is the most abundant phyllosilicate mineral in highly weathered soils. in this work, the adsorption kinetics of maxilon yellow 4GL (MY 4GL) and maxilon red GRL (MR GRL) dyes on kaolinite from aqueous solutions was investigated using the parameters such as contact time. stirring speed, initial dye concentration, initial pH, ionic strength, acid-activation, calcination and solution temperature. The equilibrium time was 150 min for both dyes. The results showed that alkaline pH was favorable for the adsorption of MY 4GL and MR GRL dyes and physisorption seemed to play a major role in the adsorption process. It was found that the rate of adsorption decreases with increasing temperature and the process is exothermic. The adsorption kinetics followed the pseudo-second-order equation for both dyes investigated in this work with the k(2) values lying in the region of 1.7910⁴ to 107.8710⁴ g/mol min for MY 4GL and 3.4410⁴ to 72.0910⁴ g/mol min for MR GRL. The diffusion coefficient values calculated for the dyes were in the range of 3.7610^-9 to 62.5010^-9 cm²/s for MY 4GL and 1.9810^-9 to 44.0010^-9 cm²/s for MR GRL, and are compatible with other studies reported in the literature. The thermodynamic activation parameters such as the enthalpy, entropy and free energy were determined. The obtained results confirmed the applicability of this clay as an efficient adsorbent for cationic dyes. (c) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Activation Parameters, Adsorption, Agricultural Waste, Aqueous-Solutions, Dyes, Electrokinetic Properties, Fly-Ash, Kaolinite, Kinetics, Linked Chitosan Beads, Malachite-Green, Methylene-Blue, pH, Reactive Dyes, Waste-Water

? Tajar, A.F., Kaghazchi, T. and Soleimani, M. (2009), Adsorption of cadmium from aqueous solutions on sulfurized activated carbon prepared from nut shells. Journal of Hazardous Materials, 165 (1-3), 1159-1164.

Full Text: 2009\J Haz Mat165, 1159.pdf

Abstract: Low-cost activated carbon, derived from nut shells, and its modified sample have been used as replacements for the current expensive methods of removing cadmium from aqueous solutions and waste waters. Adsorption of cadmium onto four kinds of activated carbons has been studied; prepared activated carbon (PAC), commercial activated carbon (CAC), and the sulfurized ones (SPAC & SCAC). The activated carbon has been derived, characterized, treated with sulfur and then utilized for the removal of Cd²⁺. Sulfurizing agent (SO2 gas) was successfully used in adsorbents’ modification process at the ambient temperature. Samples were then characterized and tested as adsorbents of cadmium. Effect of some parameters such as contact time, initial concentration and pH were examined. With increasing pH, the adsorption of cadmium ions was increased and maximum removal, 92.4% for SPAC, was observed in pH > 8.0 (C-0 = 100 mg/L). The H-type adsorption isotherms, obtained for the adsorbents, indicated a favorable process. Adsorption data on both prepared and commercial activated carbon, before and after sulfurization, followed both the Frendlich and Langmuir models. They were better fitted by Frendlich isotherm as compared to Langmuir. The maximum adsorption capacities were 90.09, 104.17, 126.58 and 142.86 mg/g for CAC, PAC, SCAC and SPAC, respectively. Accordingly, surface modification of activated carbons using SO2 greatly enhanced cadmium removal. The reversibility of the process has been studied in a qualitative manner and it shows that the spent SPAC can be effectively regenerated for further use easily. (c) 2008 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Activated Carbon, Cadmium Removal, Modification, Sulfur, Langmuir & Frendlich Isotherms, Low-Cost Adsorbents, Heavy-Metals, Zinc, Removal, Mercury, Copper, Waste, Water, Cloth, pH

? Xu, H.Y., Prasad, M. and Liu, Y. (2009), Schorl: A novel catalyst in mineral-catalyzed Fenton-like system for dyeing wastewater discoloration. Journal of Hazardous Materials, 165 (1-3), 1186-1192.

Full Text: 2009\J Haz Mat165, 1186.pdf

Abstract: Mineral-catalyzed Fenton-like system has been found to be effective for the discoloration of dyeing wastewater. In our present study, schorl has been successfully developed as a novel heterogeneous catalyst for discoloration of an active commercial dye, Argazol blue (BF-BR), in an aqueous solution. Through a number of batch discoloration experiments under various conditions, it was found that the reactivity of the system increased by, respectively, increasing schorl dosage, temperature, hydrogen peroxide starting concentration and by decreasing the pH. At the condition of pH 2, T=55 degrees C, [BF-BR](0) = 200 mg/L, [H(2)O(2)](0) = 48.5 mmol/L and schorl dosage = 10g/L. 100% of discoloration ratio can be achieved in less than 4 min, and 72% of total organic carbon (TOC) can be removed in less than 200 min. The reaction kinetics analysis shows that the discoloration of BF-BR follows the first-order kinetics. The schorl samples after BF-BR discoloration was tested by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Scanning electron microscope (SEM) and the results rule out the possibility of formation of new solid phases during BF-BR discoloration. The content of Fe ion leaching in the Solution was also measured using inductively coupling plasma-atomic emission spectra (ICP-AES). A mechanism proposed herein indicates adsorption and Fenton-like reaction (heterogeneous and homogeneous) are responsible for the discoloration of BF-BR. (c) 2008 Elsevier B,V. All rights reserved.

Keywords: 2-Chlorophenol, Adsorption, Analysis, Argazol Blue, Decomposition, Discoloration, First Order, FTIR, Goethite, Hydrogen-Peroxide, Iron, Kinetics, Mechanism, Mineral-Catalyzed Fenton-Like System, Optimization, Organic-Compounds, Oxidation, Peroxide, Ph, Piezoelectric Properties, Ratio, Schorl, SEM, TOC, Tourmaline, Wastewater, X-Ray Diffraction, XRD

? Eren, E. (2009), Investigation of a basic dye removal from aqueous solution onto chemically modified Unye bentonite. 166 (1), 88-93.

Full Text: 2009\J Haz Mat166, 88.pdf

Abstract: The adsorption behavior of crystal violet (CV+) from aqueous solution onto magnesium-oxide coated bentonite (MCB) sample was investigated as a function of parameters such as initial CV+ concentration, contact time and temperature. The Langmuir, and Freundlich adsorption models were applied to describe the equilibrium isotherms. The Langmuir monolayer adsorption capacity of MCB were estimated as 496 mg/g. The pseudo-first-order, pseudo-second-order kinetic and the intra-particle diffusion models were used to describe the kinetic data and rate constants were evaluated. The values of the energy (E-a), enthalpy (Delta H-not equal) and entropy of activation (Delta S-not equal) were 56.45 kJ/mol, 53.90 kJ/mol and -117.26 J/mol K, respectively, at pH 6.5. (C) 2008 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Activation, Adsorption, Adsorption Behavior, Adsorption Capacity, Adsorption-Kinetics, Agricultural Waste, Aqueous Solution, Basic Dye, Basic Dye Removal, Behavior, Bentonite, Capacity, Cationic Dye, Clay, Coated, Component Systems, Concentration, Crystal Violet, Data, Diffusion, Diffusion Models, Dye, Dye Adsorption, Dye Removal, Energy, Enthalpy, Entropy, Equilibrium, Equilibrium Isotherms, Fly-Ash, Freundlich, Function, Intra-Particle Diffusion, Intraparticle Diffusion, Isotherms, Kinetic, Kinetic Data, Kinetics, Langmuir, Models, Modified, Modified Diatomite, Monolayer, Organic Cation, pH, Pseudo First Order, Pseudo Second Order, Pseudo Second Order Kinetic, Pseudo-First-Order, Pseudo-Second-Order, Rate Constants, Removal, Rights, Solution, Temperature, X-Ray Diffraction, Zinc Sorption

? Eren, E. (2009), Investigation of a basic dye removal from aqueous solution onto chemically modified Unye bentonite. Journal of Hazardous Materials,