Personal Research Database

Full Text: 2007\J Haz Mat139, 116.pdf

Abstract:The ability of sawdust (treated and untreated) waste, a waste material derived from the commercial processing of cedrus deodar wood for furniture production, to remove/preconcentrate Cd(II) ions from aqueous solution was determined. Sorption was found to be rapid (~ 97 % within 8 minutes). The binding of metal ions was found to be pH dependent, optimal sorption accruing at around pH 4-8. Potentiometeric titrations of sawdust revealed two distinct pKa values, the first having the value similar to carboxylic groups (3.3-4.8) and second comparable with that of amines (8.53-10.2) with the densities 1.99×10^-4 and 7.94×10^-5 respectively. Retained Cd(II) ions were eluted with 5 ml 0.1 mol l^–1 HCl. Detection limit of 0.016 μg ml^–1 was achieved with enrichment factors of 120. Recovery was quantitative using sample volume of 600 ml. The Langmuir and D-R isotherm equations were used to describe partitioning behavior for the system at different temperatures. Kinetic and thermodynamic behavior of sawdust for Cd(II) ions removal was also studied.

Keywords: Adsorption, Amines, Behavior, Binding, Biosorption, Cadmium, Cd(II), Cd(II) Ions, Densities, Enrichment, Enrichment Factors, Groups, Hcl, Isotherm, Kinetics, Langmuir, Metal, Metal Ions, Partitioning, pH, Preconcentration, Processing, Production, Removal, Sawdust, Sorption, Thermodynamic, Thermodynamics, Waste, Wood

? Pérez-Marín, A.B., Meseguer, V., Ortuño, J.F., Aguilar, M., Sáez, J. and Lloréns, M. (2007), Removal of cadmium from aqueous solutions by adsorption onto orange waste. Journal of Hazardous Materials, 139 (1), 122-131.

Full Text: 2007\J Haz Mat139, 122.pdf

Abstract: The use of orange wastes, generated in the orange juice industry, for removing cadmium from aqueous solutions has been investigated. The material was characterized by Fourier Transform Infrared Spectroscopy and batch experiments were conducted to determine the adsorption capacity of the biomass. A strong dependence of the adsorption capacity on pH was observed, the capacity increasing as pH value rose. Kinetics and adsorption equilibrium were studied at different pH values (4, 5 and 6). The adsorption process was quick and the equilibrium was attained within 3h. The maximum adsorption capacity of orange waste was found to be 0.40, 0.41 and 0.43 mmol/g at pH 4, 5 and 6, respectively. The kinetic data were analysed using various kinetic models – pseudo-first order equation, pseudo-second order equation, Elovich equation and intraparticle diffusion equation – and the equilibrium data were tested using four isotherm models – Langmuir, Freundlich, Sips and Redlich-Peterson. The data were fitted by non-linear regression and five error analysis methods were used to evaluate the goodness of the fit. The Elovich equation provides the greatest accuracy for the kinetic data and the Sips model the closest fit for the equilibrium data.

Keywords: Accuracy, Adsorption, Adsorption Capacity, Adsorption Equilibrium, Adsorption Process, Analysis, Batch Experiments, Biomass, Biosorption, Bone Char, Cadmium, Capacity, Copper(II), Dependence, Diffusion, Divalent Metal-Ions, Elovich Equation, Equilibrium, Error Analysis, Fourier Transform Infrared Spectroscopy, Freundlich, Heavy-Metals, Infrared Spectroscopy, Isotherm, Isotherm Models, Isothermal, Kinetic, Kinetic Models, Kinetics, Langmuir, Methods, Model, Models, Orange Waste, pH, pH Values, Pseudo-First Order, Pseudo-Second Order, Pseudo-Second-Order, Single, Sorption, Spectroscopy, Waste, Wastes, Water

? Noroozi, B., Sorial, G.A., Bahrami, H. and Arami, M. (2006), Equilibrium and kinetic adsorption study of a cationic dye by a natural adsorbent - Silkworm Pupa. Journal of Hazardous Materials, 139 (1), 167-174.

Full Text: 2007\J Haz Mat139, 167.pdf

Abstract: In this work the use of silkworm pupa, which is the waste of silk spinning industries has been investigated as an adsorbent for the removal of C. I. Basic Blue 41. The amino acid nature of the pupa provided a reasonable capability for dye removal. Equilibrium adsorption isotherms and kinetics were investigated. The adsorption equilibrium data were analyzed by using various adsorption isotherm models and the results have shown that adsorption behavior of the dye could be described reasonably well by either Langmuir or Freundlich models. The characteristic parameters for each isotherm have been determined. The monolayer adsorption capacity was determined to be 555 mg/g. Kinetic studies indicated that the adsorption follows pseudo second-order kinetics with a rate constant of 0.0434 and 0.0572 g/min mg for initial dye concentration of 200 mg/l at 20C and 40C, respectively. Kinetic studies showed that film diffusion and intra-particle diffusion were simultaneously operating during the adsorption process. The rate constant for intra-particle diffusion was estimated to be 1.985 mg/g min^0.5.

Keywords: Adsorbent, Adsorption, Adsorption Behavior, Adsorption Capacity, Adsorption Equilibrium, Adsorption Isotherm, Adsorption Isotherm Models, Adsorption Isotherms, Adsorption Kinetics, Adsorption Process, Amino Acid, Basic Blue 41, Behavior, Capacity, Cationic Dye, Concentration, Data, Diffusion, Dye, Dye Removal, Equilibrium, Film Diffusion, Freundlich, Intra-Particle Diffusion, Intraparticle Diffusion, Isotherm, Isotherms, Kinetic, Kinetic Adsorption, Kinetic Studies, Kinetics, Langmuir, Models, Monolayer, Natural, Pseudo Second Order, Pseudo Second Order Kinetics, Pseudo-Second-Order, Pseudo-Second-Order Kinetics, Rate Constant, Removal, Silkworm Pupa, Waste, Work

? Velpandian, T., Saha, K., Ravi, A.K., Kumari, S.S., Biswas, N.R. and Ghose, S. (2007), Ocular hazards of the colors used during the festival-of-colors (Holi) in India--Malachite green toxicity. Journal of Hazardous Materials, 139 (2), 204-208.

Full Text: 2007\J Haz Mat139, 204.pdf

Abstract: The objective of this study was to evaluate the nature of the colors used and their toxicity to the eye upon exposure to them during celebration of Holi (our festival-of-colors). Color powders and formulations were procured at random in and around Delhi during the festival. The green, bluish-green colors reported with the higher incidence of ocular toxicity were subjected for further evaluation. Eyewash fluid collected from the patients exposed to the colors was also subjected for analysis. This study was further extended to evaluate the corneal penetration of malachite green using goat cornea in perfusion chamber. In 16, 18 color samples collected, malachite green or 4-[(4-dimethylaminophenyl)-phenyl-methyl]-N,N-dimethyl-aniline was detected at different concentrations. In the eyewash fluid of four patients, HPLC estimation confirmed the presence of malachite green at concentrations of 1.3, 0.18, 3.5 and 5.4 g in 250 ml which was responsible for its reported toxicity. The in vitro trans-corneal penetration studies did not show any detectable amount of malachite green in effluent fluid--in vitro tissue retention studies revealed that increasing the contact time increases tissue concentration. After 2 min of exposure, the tissue concentration was significantly higher. To conclude, malachite green was extensively used in our festival of Holi and has caused severe ocular irritation with epithelial defect upon exposure, though it did not penetrate through the cornea--further in vitro and in vivo studies are required on colors used in Holi.

Keywords: Analysis, Concentration, Evaluation, Exposure, Eye Toxicity, Goat, Holi Festival, HPLC, Incidence, Malachite Green, Patients, Retention, Synthetic Colors, Toxicity

? Wang, S.B., Li, L. and Zhu, Z.H. (2007), Solid-state conversion of fly ash to effective adsorbents for Cu removal from wastewater. Journal of Hazardous Materials, 139 (2), 254-259.

Full Text: 2007\J Haz Mat139, 254.pdf

Abstract: Solid-state conversion of fly ash to an amorphous aluminosilicate adsorbent (geopolymer) has been investigated under different conditions and the synthesised material has been tested for Cu²⁺ removal from aqueous solution. It has been found that higher reaction temperature and Na:FA ratio will make the adsorbents achieving higher removal efficiency. The adsorbent loading and Cu²⁺ initial concentration will also affect the removal efficiency while the adsorption capacity exhibits similarly at 30–40 °C. The adsorption capacity of the synthesised adsorbent shows much higher value than fly ash and natural zeolite. The capacity is 0.1, 3.5 and 92 mg/g, for fly ash, natural zeolite, and FA derived adsorbent, respectively. The kinetic studies indicate that the adsorption can be fitted by the second-order kinetic model. Langmuir and Freundlich isotherms also can fit to the adsorption isotherm.

Keywords: Adsorbent, Adsorbents, Adsorption, Adsorption Capacity, Adsorption Isotherm, Affect, Aluminosilicate, Amorphous, Ash, Capacity, Concentration, Conversion, Copper(II), Cu, Cu²⁺, Cu²⁺ Removal, Efficiency, Fly Ash, Freundlich, Geopolymer, Geopolymers, Isotherm, Isotherms, Kinetic, Kinetic Model, Langmuir, Loading, Metals, Model, Natural, Natural Zeolite, Reaction, Removal, Removal Efficiency, Solid-State Reaction, Temperature, Wastewater, Wastewater Treatment, Zeolite, Zeolites

? Ncibi, M.C., Mahjoub, B. and Seffen, M. (2007), Kinetic and equilibrium studies of methylene blue biosorption by Posidonia oceanica (L.) fibres. Journal of Hazardous Materials, 139 (2), 280-285.

Full Text: 2007\J Haz Mat139, 280.pdf

Abstract: Batch biosorption experiments were carried out for the removal of methylene blue, a basic dye, from aqueous solution using raw Posidonia oceanica (L.) fibres, a marine lignocellulosic biomass. A series of assays were undertaken to assess the effect of the system variables, i.e. contact time, solution pH, biosorbent dosage and initial dye concentration. The results had showed that biosorption capacity was optimal using 6–9 solution pH range and by increasing the biosorbent concentration up to 1 g/L. The biosorption kinetics were analyzed using irreversible-first-order, reversible-first-order and pseudo-second-order and the sorption data were very well described by the pseudo-second-order model for the entire adsorption time with squared correlation coefficients equal to unity for all experimented initial dye concentrations. Besides, equilibrium data were very well represented by both Langmuir and Redlich–Peterson isotherm models followed by Freundlich, which confirm the monolayer coverage of methylene blue molecules onto P. oceanica fibres.

Keywords: Adsorption, Aqueous Solution, Basic Dye, Biofibres, Biomass, Biosorbent, Biosorption, Biosorption Kinetics, Capacity, Concentration, Correlation, Coverage, Data, Dye, Equilibrium, Equilibrium Studies, Experiments, Freundlich, Isotherm, Isotherms, Kinetic, Kinetics, Langmuir, Methylene Blue, Model, Modelling, Models, Monolayer, P, pH, Posidonia Oceanica, Pseudo Second Order, Pseudo-Second-Order, Pseudo-Second-Order Model, Redlich-Peterson, Removal, Solution, Sorption

? Bhakat, P.B., Gupta, A.K. and Ayoob, S. (2007), Feasibility analysis of As(III) removal in a continuous flow fixed bed system by modified calcined bauxite (MCB). Journal of Hazardous Materials, 139 (2), 286-292.

Full Text: 2007\J Haz Mat139, 286.pdf

Abstract: This study examine the feasibility of As(III) removal from aqueous environment by an adsorbent, modified calcined bauxite (MCB) in a continuous flow fixed bed system. MCB exhibited excellent adsorption capacity of 520.2 mg/L (0.39 mg/g) with an adsorption rate constant 0.7658 L/mg h for an influent As(III) concentration of 1 mg/L. In a 2 cm diameter continuous flow fixed MCB bed, a depth of only 1.765 cm was found necessary to produce effluent As(III) concentration of 0.01 mg/L, from an influent of 1 mg/L at a flow rate of 8 mL/min. Also, bed heights of 10, 20, and 30 cm could treat 427.85, 473.88 and 489.17 bed volumes of water, respectively, to breakthrough. A reduction in adsorption capacity of MCB was observed with increase in flow rates. The theoretical service times evaluated from bed depth service time (BDST) approach for different flow rates and influent As(III) concentrations had shown good correlation with the corresponding experimental values. The theoretical breakthrough curve developed from constantly mixed batch reactor (CMBR) isotherm data also correlated well with experimental breakthrough curve.

Keywords: Adsorbent, Adsorption, Adsorption, Adsorption Capacity, Adsorption Rate, Analysis, Arsenic Removal, Arsenite, BDST Model, Behavior, Breakthrough Curve, Capacity, Column Studies, Concentration, Concentrations, Contaminated Water, Correlation, Effluent, Environment, Equilibrium, Fixed Bed, Flow, Groundwater, Iron, Isotherm, Kinetics, Modified, Oxide-Coated Cement, Rate Constant, Reactor, Reduction, Removal, Sorption, Water

? Liang, C.H. and Chiang, P.C. (2007), Mathematical model of the non-steady-state adsorption and biodegradation capacities of BAC filters. Journal of Hazardous Materials, 139 (2), 316-322.

Full Text: 2007\J Haz Mat139, 316.pdf

Abstract: This research was focused on developing a non-steady-state numerical model to differentiate the adsorption and biodegradation quantities of a biological activated carbon (BAC) column. The mechanisms considered in this model included adsorption, biodegradation, convection and diffusion. Simulations were performed to evaluate the effects of some parameters such as specific biodegradation rates and diffusivities on adsorption and biodegradation performances for the removal of dissolved organic matter from water. The results show that the developed model can predict the experimental data well.

The biofilm developed around the BAC granules can hinder the mass transfer of the substrate onto the GAC surface, and the adsorption process will be restricted by the biofilm thickness. Although increasing the specific biodegradation rate can increase the performance of biodegradation, the adsorption efficiency will be decreased by lowering the boundary concentration in the interface of GAC. On the contrary, increasing the diffusivity can increase both the adsorption and biodegradation efficiencies simultaneously; so that the overall removal efficiency can be promoted through the improvement of mass transfer.

Keywords: Activated Carbon, Adsorption, Adsorption Process, Biodegradation, Biofilm, Biological Activated Carbon, Biological Activated Carbon (BAC), BOM Removal, Carbon, Concentration, Convection, Detachment, Diffusion, Dissolved, Dissolved Organic Matter, Drinking-Water Biofilters, Effects, Efficiency, GAC, Granular Activated Carbon (GAC), Growth, Interface, Mass Transfer, Matter, Mechanisms, Model, Non-Steady-State, Numerical, Numerical Model, Organic, Organic Matter, Parameters, Performance, Predict, Removal, Removal Efficiency, Research, Simulation, Substrate, Surface, Transfer, Water

? Zhong, J.B., Wang, J.L., Tao, L., Gong, M.C., Liu, Z.L. and Chen, Y.Q. (2007), Photocatalytic degradation of gaseous benzene over TiO₂/Sr₂CeO₄: Kinetic model and degradation mechanisms. Journal of Hazardous Materials, 139 (2), 323-331.

Full Text: 2007\J Haz Mat139, 323.pdf

Abstract: Photocatalytic oxidation of benzene in air was carried out over TiO₂/Sr₂CeO₄ catalysts. The prepared photocatalyst was characterized by S-BET, UV-vis diffuse reflectance and XPS. TiO₂/Sr₂CeO₄ absorbs much more visible light than TiO₂ in the visible light region. The XPS spectrum shows that the binding energy value of Ti 2p(3/2) transfers to a lower value. The main purpose was to investigate the kinetic model and degradation mechanisms. The kinetic data matched well with the Langmuir-Hinshelwood (L-H) kinetic model with the limiting rate constant and the adsorption constant in this case were 0.0064 mg l^-1 min^-1 and 9.2078 l mg^-1, respectively. No gas-phase intermediates were detected by direct GC/FID analysis under the conditions despite the high benzene concentration. Ethyl acetate and (3-methyl-oxiran-2-yl)-methanol were two major identified intermediates which were accompanied by butylated hydroxytoluene, 2,6-bis(1,1-dimethylethyl)-4,4-dimethylycyclohe, 2,5-cyclohexadiene- 1,4,dione,2,6-bis(1, 1-dim). It is plausible that at least one of these less-reactive intermediates caused the deactivation of the photocatalyst. Finally, the photocatalytic oxidation mechanisms were speculated. (c) 2006 Elsevier B.V. All rights reserved.

Keywords: Acetate, Adsorption, Air, Analysis, Benzene, Binding, Catalysts, Concentration, Decomposition, Degradation, Degradation Mechanisms, Energy, Gas Phase, Gas-Phase, GC, FID, Humidified Air, Indoor Air, Kinetic, Kinetic Model, LH, Light, Mechanisms, Model, Oxidation, Photocatalytic Degradation, Photocatalytic Oxidation, Rate Constant, Reflectance, TiO₂, Titanium-Dioxide, Toluene, Vapor, Volatile Organic-Compounds, XPS

? Deng, X., Yi, X.E. and Liu, G. (2007), Cadmium removal from aqueous solution by gene-modified Escherichia coli JM109. Journal of Hazardous Materials, 139 (2), 340-344.

Full Text: 2007\J Haz Mat139, 340.pdf

Abstract: The article extended the study on the bioaccumulation of cadmium by genetically engineered bacterium Escherichia coli (namely M4) simultaneously expressing a cadmium transport system and metallothionein (MT). The growth of M4 showed resistance to the presence of cadmium. Compared with Cd²⁺ uptake capacity by original host bacterial cells, The Cd²⁺ accumulation of M4 was enhanced more than one-fold. M4 could effectively bind Cd²⁺ over a range of pH from 4 to 8. The presence of Ni²⁺ and Mn²⁺ did not influence Cd²⁺ uptake remarkably, but Cu²⁺, Pb²⁺ and Zn²⁺ posed serious adverse effects. EDTA could drastically decrease Cd²⁺ bioaccumulation by M4, whereas the effect of citrate was relatively slight.

Keywords: Accumulation, Adverse Effects, Bioaccumulation, Bioaccumulation, Bioremediation, Biosorption, Cadmium, Capacity, Cells, Citrate, Cu²⁺, EDTA, Effects, Equilibrium, Escherichia Coli, Expression, Genetically Engineered Escherichia Coli, Growth, Heavy Metal Wastewater, Lactobacillus-Plantarum, Metallothionein, Metals, Nickel, Pb²⁺ and Zn²⁺, pH, Pretreated Biomass, Range, Removal, Resistance, Transport, Uptake, Zn²⁺

? Hanif, M.A., Nadeem, R., Bhatti, H.N., Ahmad, N.R. and Ansari, T.M. (2007), Ni(II) biosorption by Cassia fistula (Golden Shower) biomass. Journal of Hazardous Materials, 139 (2), 345-355.

Full Text: 2007\J Haz Mat139, 345.pdf

Abstract: Cassia fistula is a fast-growing, medium-sized, deciduous tree which is now widely cultivated worldwide as an ornamental tree for its beautiful showy yellow flowers. Methods are required to reuse fallen leaves, branches, stem bark and pods when they start getting all over lawn. This investigation studies the use of these non-useful parts of C. fistula as naturally occurring biosorbent for the batch removal of Ni(II) in a well stirred system under different experimental conditions. The data showed that the maximum pH (pH_max) for efficient sorption of Ni(II) was 6 at which evaluated biosorbent dosage, biosorbent particle size, initial concentrations of Ni(II) and sorption time were 0.1 g/100 mL, <0.255 mm, up to 200 mg/L and 720 min, respectively. The experimental results were analyzed in terms of Langmuir and Freundlich isotherms. The Langmuir isotherm model fitted well to data of Ni(II) biosorption by C. fistula biomass as compared to the model of Freundlich. The kinetic studies showed that the sorption rates could be described better by a second order expression than by a more commonly applied Lagergren equation. The magnitude of the Gibbs free energy values indicates spontaneous nature of the sorption process. The sorption ability of C. fistula biomass for Ni(II) removal tends to be in the order: leaves < stem bark < pods bark. One hundred percent Ni(II) removal was achieved when the initial Ni(II) concentration was 25 mg/L. Due to its outstanding Ni(II) uptake capacity, C. fistula biomass proved to be an excellent biomaterial for accumulating Ni(II) from aqueous solutions.

Keywords: Aqueous-Solutions, Arthrobacter-Sp, Basic Dye, Biomass, Biosorbent, Biosorption, Capacity, Cassia Fistula, Concentration, Concentrations, Copper, Deciduous, Dosage, Energy, Equilibrium, Equilibrium, Freundlich, Heavy-Metals, Ions, Isotherm, Isotherms, Kinetic, Kinetics, Langmuir, Leaves, Model, Ni(II), Particle, Particle Size, pH, Removal, Reuse, Sorption, Sorption, Toxic Metals, Tree, Uptake

? Ofomaja, A.E. and Ho, Y.S. (2007), Effect of pH on cadmium biosorption by coconut copra meal. Journal of Hazardous Materials, 139 (2), 356-362.

Full Text: 2007\J Haz Mat139, 356.pdf; 2006\J Haz Mat-Ofomaja.pdf

Abstract: Biosorption of cadmium ion by coconut copra meal, an agricultural waste product was investigated as a function of initial solution pH and initial cadmium concentration. Pseudo-second-order kinetic analyses were performed to determine the rate constant of biosorption, the equilibrium capacity, and initial biosorption rate. Cadmium biosorption by copra meal was found to be dependent on the initial solution pH and initial cadmium concentration. Ion exchange occurred in the initial biosorption period. In addition, mathematical relationships were drawn to relate the change in the solution hydrogen ion concentration with equilibrium biosorption capacity, initial cadmium concentration, and equilibrium biosorption capacity.

Keywords: Agricultural, Agricultural Waste, Analyses, Biosorption, Cadmium, Cadmium Biosorption, Cadmium Ions, Capacity, Concentration, Copra Meal, Equilibrium, Function, Hydrogen, Hydrogen Ion Concentration, Ion Exchange, Ion-Exchange, Kinetic, pH, Pseudo-Second-Order, Pseudo-Second-Order Kinetics, Rate Constant, Solution, Sorption, Waste

? Baillez, S., Nzihou, A., Bernache-Assolant, D., Champion, E. and Sharrock, P. (2007), Removal of aqueous lead ions by hydroxyapatites: Equilibria and kinetic processes. Journal of Hazardous Materials, 139 (3), 443-446.

Full Text: 2007\J Haz Mat139, 443.pdf

Abstract: The capacity of hydroxyapatite (HAp) to remove lead from aqueous solution was investigated under different conditions, namely initial metal ion concentration and reaction time. The sorption of lead from solutions containing initial concentrations from 0 to 8000 mg/L was studied for three different HAp powders. Soluble Pb and Ca monitoring during the experiment allows characterizing the mechanism of lead uptake. Dissolution of calcium is followed by the formation of a solid solution, Pb_xCa_10−x(PO₄)₆(OH)₂, with a Ca/P ratio decreasing continuously. Langmuir–Freundlich classical adsorption isotherms modeled adsorption data. The adsorption capacities calculated from this equation vary from 330 to 450 mg Pb/g HAp for the different solids. Modeling of the sorption process allows to determine theoretical saturation times and residual lead concentrations at equilibrium.

Keywords: Adsorption, Adsorption Isotherms, Apatite, Calcium, Capacity, Co(II), Concentration, Concentrations, Equilibrium, Experiment, Hydroxyapatite, Immobilization, Ion, Isotherms, Kinetic, Langmuir-Freundlich, Lead, Lead Ions, Mechanism, Metal, Monitoring, Pb, Reaction, Saturation, Sorption, Uptake, Waste-Water

? Karageorgiou, K., Paschalis, M. and Anastassakis, G.N. (2007), Removal of phosphate species from solution by adsorption onto calcite used as natural adsorbent. Journal of Hazardous Materials,