Personal Research Database

Full Text: 2007\J Haz Mat147, 513.pdf

Abstract: Important pumice quarries are located on the island of Lipari (Italy) where an intense activity of extraction, transformation and trade of pumice takes place. Nevertheless, the finest fraction amounting to about 60% of mined pumice is discarded and disposed off in open-sky pits. This implies economic losses for mining industries and environmental problems for neighbouring villages. In order to find a sustainable use of this waste, we resumed and improved an old extractive process with aqueous sodium alkali, where a sodium silicate concentrated solution was produced together with an unextracted residue partially converted into zeolite P in Na+ form and now we are searching for suitable applications of this residue.

In this paper, we relate about its use as a low cost water softening agent on the basis of results obtained from several tests both in batch systems and column. They show that, at room temperature, the residue works well with calcium and badly with magnesium, whereas, at 60 degrees C, also the affinity toward Mg ions increases to acceptable levels.

Repeated regenerations of the residue with concentrated NaCl solutions do not appreciably compromise the performance. The limits for the possible use as water softening agent are defined. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Ion Exchange, Zeolite, Water Softening, Pumice Mine Wastes, Ion-Exchange, Map

? Ozturk, A. (2007), Removal of nickel from aqueous solution by the bacterium Bacillus thuringiensis. Journal of Hazardous Materials, 147 (1-2), 518-523.

Full Text: 2007\J Haz Mat147, 518.pdf

Abstract: The biosorption of the toxic metal (nickel) from aqueous solutions on dried vegetative cell and spore-crystal mixture of Bacillus thuringiensis var. thuringiensis was tested under laboratory conditions as a function of pH, initial metal ion concentration and temperature. The characteristics of the adsorption process were investigated using Scatchard analysis. Scatchard analysis of the equilibrium binding data for metal ions on vegetative cell and spore-crystal mixture of B. thuringiensis gave rise to a linear plot, indicating that the Langmuir model could be applied successfully. Adsorption behaviour of nickel(H) ion on B. thuringiensis is expressed by both Langmuir and Freundlich isotherms. The adsorption data with respect to the metal provided an excellent fit to both isotherms. Ni(II) ion uptake of B. thuringiensis’s spore-crystal mixture at 250 mg l^-1 was 15.7%, whereas its vegetative cell metal uptake was 10%. The best temperature for ion uptake was found to be at 35C. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: B. Thuringiensis, Biosorption, Nickel Ions, Toxic Metal Removal, Heavy-Metal Biosorption, Ions, Biosorbents, Adsorption, Binding, Biomass, Algae, Cells

? El-Shafey, E.I. (2007), Sorption of Cd(II) and Se(IV) from aqueous solution using modified rice husk. Journal of Hazardous Materials, 147 (1-2), 546-555.

Full Text: 2007\J Haz Mat147, 546.pdf

Abstract: A carbonaceous sorbent was prepared from rice husk via sulfuric acid treatment. Removal of Cd(II) and Se(IV) from aqueous solution was studied varying time, pH, metal concentration, temperature and sorbent status (wet and dry). Cd(II) sorption was found fast reaching equilibrium within similar to 2 h while Se(IV) sorption was slow reaching equilibrium within similar to 200 h with better performance for the wet sorbent than for the dry. Kinetics data for both metals were found to follow pseudo-second order model. Cd(II) sorption was low at low pH values and increased with pH increase, however, Se(IV) sorption was high at low pH values, and decreased with the rise in initial pH until pH 7. A fall in the final pH was noticed with Cd(II) sorption due to the release of protons indicating an ion exchange mechanism. However, for Se(IV) sorption, a rise in the final pH was observed due to protons consumption in the process. For both metals, sorption fit well the Langmuir equation with higher uptake by rising the temperature. Analysis by scanning electron microscope and X-ray powder diffraction for the sorbent after the reaction with acidified Se(IV) confirmed the availability of elemental selenium, Se(0), as particles on the sorbent surface. The reduction process of acidified Se(IV) to Se(O) is accompanied by surface oxidation. Physicochemical tests showed an increase in sorbent acidity, cation exchange capacity and surface functionality after the reaction with acidified Se(W) indicating that oxidation processes took place on the sorbent surface. On the other hand, no changes in physicochemical tests were found after Cd(II) sorption indicating the absence of redox processes between Cd(II) and the sorbent. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Acid, Acid Treatment, Acid-Treatment, Acidity, Aqueous Solution, Availability, Cadmium, Capacity, Carbon, Carbonaceous, Carbonaceous Sorbent, Cation, Cation Exchange, Cation Exchange Capacity, Cd(II), Cd(II) Sorption, Coated Sand, Concentration, Consumption, Equilibrium, Fall, Flax Shive, Hand, Ion, Ion Exchange, Ion-Exchange, Langmuir, Langmuir Equation, Low, Mechanism, Metal, Metal-Ions, Metals, Model, Modified, Modified Rice Husk, Order, Oxidation, Particles, Performance, pH, pH Values, Powder, Preconcentration, Process, Pseudo Second Order, Pseudo-Second Order, Pseudo-Second Order Model, Pseudo-Second-Order, Reaction, Redox, Reduction, Release, Removal, Rice, Rice Husk, Se(IV), Selenium, Selenium Adsorption, Sorbent, Sorption, Sulfuric Acid, Surface, Surface Functionality, Temperature, Tests, Time, Treatment, Uptake, Waste-Water

? Álvarez-Ayuso, E. and García-Sánchez, A. (2007), Removal of cadmium from aqueous solutions by palygorskite. Journal of Hazardous Materials, 147 (1-2), 594-600.

Full Text: 2007\J Haz Mat147, 594.pdf

Abstract: The sorption characteristics of palygorskite with respect to cadmium were studied with the aim of assessing its use in water purification systems. Using a batch method the influence of time (0.5-48h), initial Cd concentration (5-150mg/l or 0.044-1.34mmol/1), ionic strength ([Ca(H)]: 0-0.1 mol/l), pH (3-7) and mineral dose (1-20 g/l) on Cd removal was evaluated. The sorption of Cd on palygorskite appeared as a fast process, with equilibrium being attained within the first half an hour of interaction. This process could be described by the Langmuir model and gave a maximum Cd sorption of 4.54 mg/g. This sorption capacity value was greatly affected by both pH and ionic strength. Thus, Cd sorption decreased as initial pH lessened, especially at proton concentrations similar to those of Cd, at which competition for variable charge sites (silanol groups on palygorskite surface) appeared to be important. High competing electrolyte concentrations also decreased significantly (close to 60%) the amount of sorbed Cd, suggesting a great contribution of replacement of exchange cations in this metal removal by palygorskite. The increase of mineral dose provoked a Cd removal raise; removal values in the range 85-45% were attained for Cd initial concentrations of 10-150 mg/l (0.089-1.34 mmol/l) when a palygorskite dose of 20 g/l was employed. Column studies were also performed in order to estimate the potential of palygorskite to be used in continuous flow purification systems, showing the effectiveriess of this mineral to purify down to the legal limit of waste moderate volumes of Cd-containing solutions with a similar concentration (50 mg/l or 0.445 mmol/l) to those mostly found in the upper range of concentrations usually present in industrial wastewaters. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Palygorskite, Cadmium, Sorption, Water Purification, Waste-Waters, Transcarpathian Clinoptilolite, Pretreated Biomass, Heavy-Metals, Rice Husk, Adsorption, Biosorption, Sepiolite, Sorption, Acid

? Daifullah, A.A.M., Yakout, S.M. and Elreefy, S.A. (2007), Adsorption of fluoride in aqueous solutions using KMnO₄-modified activated carbon derived from steam pyrolysis of rice straw. Journal of Hazardous Materials, 147 (1-2), 633-643.

Full Text: 2007\J Haz Mat147, 633.pdf

Abstract: Fluoride in drinking water above permissible levels is responsible for human and skeletal fluorosis. In this study, activated carbons (AC) prepared by one-step steam pyrolysis of rice straw at 550, 650, 750C, respectively, were modified by liquid-phase oxidation using HNO₃, H₂O₂ and KMnO₄. Characterization of these 12 carbons was made by their surface area, porosity, acidity, basicity, pH(pzc), pH and ability to remove fluoride anion. Based on the data of the latter factor, the RS2/KMnO₄ Carbon was selected. Along with batch adsorption studies, which involve effect of pH, adsorbate concentration, adsorbent dosage, contact time, temperature, and Co-ions (SO₄^2-, Cl^-, Br^-). The effects of natural organic matter (NOM) were also made to remove the fluoride from natural water. On the basis of kinetic studies, specific rate constants involved in the adsorption process using RS2/KMnO₄ carbon was calculated and second-order adsorption kinetics was observed. Equation isotherms such as Langmuir (L), Freundlich (F), Langmuir-Freundlich (LF) and Dubinin-Radushkevich (DR) were successfully used to model the experimental data. From the DR isotherm parameters, it was considered that the uptake of F^- by RS2/KMnO₄ carbon proceeds by an ion-exchange mechanism (E= 10.46 kJ mol^-1). The thermodynamic parameters of fluoride sorption were calculated and the sorption process was chemical in nature. The ability of RS2/KMnO₄ to remove F^- from Egyptian crude phosphoric acid (P₂O₅ = 48.42%) was tested and the adsorption capacity of F^- in H₃PO₄ was greater than that in distilled water. This is may be due to fluoride adsorption enhanced at lower pH of crude acid. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Acid, Acidity, Activated Carbon, Activated Carbons, Adsorbent, Adsorbent Dosage, Adsorption, Adsorption Capacity, Adsorption Kinetics, Adsorption Process, Anion, Aqueous Solutions, Basicity, Batch, Batch Adsorption, Capacity, Carbon, Chemical, Concentration, Constants, Contact Time, Crude Phosphoric Acid, Defluoridation, Dosage, Drinking Water, Drinking-Water, Effect of pH, Effects, Equilibrium, Experimental, Experimental Data, Fluoride, Fluoride Adsorption, Freundlich, H₂O₂, H₃PO₄, HNO₃, Human, Ion Exchange, Ion-Exchange, Isotherm, Isotherm Parameters, Isotherms, Kinetic, Kinetic Studies, Kinetics, Langmuir, Langmuir-Freundlich, Levels, Liquid Phase, Liquid-Phase Oxidation, Low-Cost Materials, Made, Matter, Mechanism, Metal-Ions, Model, Modified, Nanotubes, Natural, Natural Organic Matter, Natural Water, Nom, Organic, Organic Matter, Oxidation, Parameters, pH, pH(Pzc), Phosphoric Acid, Porosity, Process, Pyrolysis, Rate, Rate Constants, Removal, Rice, Rice Straw, Sawdust, Second Order, SO₄^2-, SO₄^2-, Solutions, Sorption, Steam Activation, Steam Pyrolysis, Surface, Surface Area, Surface Modification, Temperature, Thermodynamic, Thermodynamic Parameters, Time, Uptake, Water

? Kumar, K.V., Porkodi, K. and Rocha, F. (2007), Comments on “Removal of lead from aqueous solution using Syzygium cumini L.: Equilibrium and kinetic studies”. Journal of Hazardous Materials, 147 (1-2), 677-678.

Full Text: 2007\J Haz Mat147, 677.pdf

Abstract: This letter reports the importance and advantages of the constraints in the Redlich–Peterson isotherm exponent.

Keywords: Isotherm, Redlich–Peterson, Langmuir, Theory, Constraints

? Kumar, K.V. and Porkodi, K. (2007), Comments on “Biosorption of nickel from protonated rice bran”. Journal of Hazardous Materials, 147 (1-2), 679.

Full Text: 2007\J Haz Mat147, 679.pdf

Abstract: This letter explains the appropriate way to calculate the parameters in pseudo first and second order kinetics, Langmuir and Freundlich isotherm.

Keywords: First, Freundlich, Freundlich Isotherm, Isotherm, Kinetics, Langmuir, Nickel, Rice, Second Order, Second Order Kinetics, Second-Order, Sorption

? Banerjee, S.S. and Chen, D.H. (2007), Fast removal of copper ions by gum Arabic modified magnetic nano-adsorbent. Journal of Hazardous Materials, 147 (3), 792-799.

Full Text: 2007\J Haz Mat147, 792.pdf

Abstract: A novel magnetic nano-adsorbent was developed by treating Fe₃O₄ nanoparticles with gum arabic to remove copper ions from aqueous solutions. Gum arabic was attached to Fe₃O₄ via the interaction between the carboxylic groups of gum arabic and the surface hydroxyl groups of Fe₃O₄. The surface modification did not result in the phase change of Fe₃O₄, while led to the formation of secondary particles with diameter in the range of 13–67 nm and the shift of isoelectric point from 6.78 to 3.6. The amount of gum arabic in the final product was about 5.1 wt%. Both the naked magnetic nanoparticles (MNP) and gum arabic modified magnetic nanoparticles (GA-MNP) could be used for the adsorption of copper ions via the complexation with the surface hydroxyl groups of Fe₃O₄ and the complexation with the amine groups of gum arabic, respectively. The adsorption rate was so fast that the equilibrium was achieved within 2 min due to the absence of internal diffusion resistance and the adsorption capacities for both MNP and GA-MNP increased with increasing the solution pH. However, the latter was significantly higher than the former. Also, both the adsorption data obeyed the Langmuir isotherm equation. The maximum adsorption capacities were 17.6 and 38.5 mg/g for MNP and GA-MNP, respectively, and the Langmuir adsorption constants were 0.013 and 0.012 L/mg for MNP and GA-MNP, respectively. Furthermore, both the adsorption processes were endothermic due to the dehydration of hydrated metal ions. The enthalpy changes were 11.5 and 9.1 kJ/mol for MNP and GA-MNP, respectively. In addition, the copper ions could desorb from GA-MNP by using acid solution and the GA-MNP exhibited good reusability.

Keywords: Nanoparticle, Magnetic, Gum arabic, Adsorption, Copper ions

? Thornton, A., Pearce, P. and Parsons, S.A. (2007), Ammonium removal from solution using ion exchange on to MesoLite, an equilibrium study. Journal of Hazardous Materials, 147 (3), 883-889.

Full Text: 2007\J Haz Mat147, 883.pdf

Abstract: This paper investigates the potential of MesoLite ion exchange media for ammonium (NH₄⁺) removal from solution in the presence of competing cations. Batch tests were performed under a range of conditions to assess the effect of contact time, solution pH and solution concentration on the performance and capacity of the media for this application. The data obtained was fitted to the Langmuir and Freundlich isotherm models with the Langmuir model providing the better description of the process. Results indicate a maximum equilibrium capacity of 49 g NH₄⁺-N kg^-1 of media is achievable under the experimental conditions studied. A detailed examination of the data shows that increasing solution concentration and increased contact time provide the best performance at an optimum pH of between 6 and 7. (c) 2007 Elsevier B.V. All rights reserved.

Keywords: Ammonium, Ion Exchange, Nutrient Removal, Wastewater, Zeolite, Natural Chinese Clinoptilolite, Aqueous-Solution, Biological Regeneration, Nitrogen Removal, Zeolite, Wastewaters, Nitrification, Sorption

? Osma, J.F., Saravia, V., Toca-Herrera, J.L. and Couto, S.R. (2007), Sunflower seed shells: A novel and effective low-cost adsorbent for the removal of the diazo dye reactive black 5 from aqueous solutions. Journal of Hazardous Materials, 147 (3), 900-905.

Full Text: 2007\J Haz Mat147, 900.pdf

Abstract: In this paper, the potential of two low-cost adsorbents such as sunflower seed shells (SS) and mandarin peelings (MP) in the removal of the synthetic anionic dye Reactive Black 5 (RB5) from aqueous solutions was investigated. SS led to a percentage of dye removal higher than MP (85% and 71% after 210 min, respectively, for an initial RB5 concentration of 50 mgL^-1 and an initial pH of 2.0). The rate of adsorption followed a pseudo-second-order kinetic model and the intra-particle diffusion was found to be the rate-controlling stage. In addition, the equilibrium data fitted well both the Freundlich and multilayer adsorption isotherm equations indicating the heterogeneity of the adsorbent surface. This was also corroborated by the SEM photographs. On the whole, the results in this study indicated that SS were very attractive materials for removing anionic dyes from dyed effluents. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Acid Dye, Activated Carbon, Adsorbent, Adsorbents, Adsorption, Adsorption Isotherm, Adsorption Isotherms, Adsorption Kinetics, Anionic, Anionic Dye, Anionic Dyes, Aqueous Solutions, Beads, Color, Concentration, Diazo Dye, Diffusion, Dye, Dye Removal, Dyes, Effective, Effluents, Equations, Equilibrium, Equilibrium Data, Freundlich, Heterogeneity, Intra Particle Diffusion, Intra-Particle Diffusion, Intraparticle Diffusion, Isotherm, Kinetic, Kinetic Model, Laccase, Low Cost Adsorbent, Low Cost Adsorbents, Low-Cost Adsorbent, Low-Cost Adsorbents, Mandarin Peelings, Materials, Model, Multilayer, Multilayer Adsorption, Natural Adsorbents, Paper, pH, Potential, Pseudo Second Order, Pseudo Second Order Kinetic, Pseudo-Second-Order, Pseudo-Second-Order Kinetic Model, Pseudo-Second-Order Kinetics, Rate, Reactive Black 5, Removal, Removing, Seed, Sem, Shells, Solutions, Sunflower Seed Shells, Surface, Synthetic, Textile Dyes

? Nigussie, W., Zewge, F. and Chandravanshi, B.S. (2007), Removal of excess fluoride from water using waste residue from alum manufacturing process. Journal of Hazardous Materials, 147 (3), 954-963.

Full Text: 2007\J Haz Mat147, 954.pdf

Abstract: The ability of waste residue, generated from alum manufacturing process, to remove fluoride ion from water has been investigated. Series of batch adsorption experiments were carried out to assess parameters that influence the adsorption process. The factors investigated include the effect of contact time, adsorbent dose, thermal pretreatment of the adsorbent, neutralization of the adsorbent, initial fluoride concentration, pH of the solution and effect of co-existing anions. Results showed that Adsorption of fluoride is fairly rapid in first 5 min and thereafter increases slowly to reach the equilibrium in about 1 h. The removal efficiency of fluoride was increased with adsorbent dosage. About 85% removal efficiency was obtained within I h at an optimum adsorbent dose of 16 g/L for initial fluoride concentration of 10 mg/L. Heat treatment and surface neutralization of the adsorbent did not improve the fluoride removal capacity and efficiency. The amount of fluoride adsorbed increased with increasing initial fluoride concentration. The percentage of fluoride removal remains nearly constant within the pH range of 3-8. The adsorption data at ambient pH were well fitted to the Dubinin-Radushkevick (D-R) isotherm model with a capacity of 332.5 mg/g of the adsorbent. The adsorption kinetic was found to follow a pseudo-second-order rate equation with an average rate constant of 2.25 g min^-1 mg^-1. The presence of bicarbonate at higher concentrations (100-500mg/L) decreased the fluoride removal efficiency while other anions (chloride, sulfate, phosphate and nitrate) have no significant effect within the concentration range tested. The overall result shows that the waste residue is efficient defluoridating material. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Adsorbent, Adsorbent Dosage, Adsorption, Adsorption Kinetic, Adsorption Process, Alum, Ambient, Anions, Aqueous-Solution, Batch, Batch Adsorption, Bentonite, Bicarbonate, Capacity, Chloride, Co-Existing Anions, Concentration, Concentrations, Contact Time, Defluoridation, Defluoridation, Dosage, Drinking-Water, Efficiency, Equilibrium, Experiments, Fluoride, Fluoride Removal, Hydroxide, Ion, Isotherm, Isotherm Model, Kinetic, Low-Cost Materials, Manufacturing, Model, Neutralization, Nitrate, Orange Peel, Parameters, pH, Phosphate, Pretreatment, Process, Pseudo Second Order, Pseudo-Second-Order, Range, Rate, Rate Constant, Rate Equation, Removal, Removal Efficiency, Residue, Sulfate, Surface, Thermal, Time, Treatment, Waste, Waste Residue, Water

? Weerasooriya, R., Tobschall, H.J., Seneviratne, W. and Bandara, A. (2007), Transition state kinetics of Hg(II) adsorption at gibbsite-water interface. Journal of Hazardous Materials, 147 (3), 971-978.

Full Text: 2007\J Haz Mat147, 971.pdf

Abstract: Kinetics of adsorption plays a pivotal factor in determining the bio-availability and mobility of Hg(II) in the environment. The kinetics of Hg(II) adsorption on gibbsite was examined as a function of pH, temperature and electrolyte type. Adsorption of Hg(II) was highly non-linear where the rate of Hg(II) retention was rapid initially and was followed by gradual or somewhat slow retention behavior with increasing contact time. The respective rate constants designated as k(1) (S-1: fast step) and k(2) (S-2: slow step). Always k(1) follows the order: k(1)(ClO4) >= k(1)((NO3)4) >> K(1)(cl). Such a relationship was not observed for the S-2 route. A two-step reaction model with pseudo-first order kinetics successfully described the adsorption rates of Hg(II) on gibbsite. Arrhemus and Frying models determined the thermodynamic parameters at activation states, which correspond to S-1 and S-2 routes. In a given system, always the activation energies showed a decrease with the pH. Gibbs free energy (Delta G(#)), enthalpy (Delta H(#)), and entropy (Delta S(#)) values of activation states were almost similar both in NaClO(4) and NaNO(3) which signal a similar Hg(II) adsorptive mechanism on gibbsite. The configurations of different Hg(II)-surface complexes were elucidated by transmission vibration spectroscopy. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Activation, Adsorption, Adsorption Kinetics, Areas, Arrhenius Model, Behavior, Bioavailability, Desorption, Energy, Environment, ERYING Model, EXAFS, Gibbs Free Energy, Hg(II), Kinetics, Mechanism, Mercury(II), Mercury(II) Sorption, Model, Pb(II), pH, Pseudo-First Order, Pseudo-First-Order, Retention, Thermodynamic, Thermodynamic Parameters, Vibration

? Wang, L. and Wang, A.Q. (2007), Adsorption characteristics of Congo Red onto the chitelsan/montmorillonite nanocomposite. Journal of Hazardous Materials, 147 (3), 979-985.

Full Text: 2007\J Haz Mat147, 979.pdf

Abstract: A series of biopolymer chitosan/montmorillonite (CTS/MMT) nanocomposites were prepared by controlling the molar ratio of chitosan (CTS) and montmorillonite (MMT). The nanocomposites were characterized by FTIR and XRD. The effects of different molar ratios of CTS and MMT, initial pH value of the dye solution and temperature on adsorption capacities of samples for Congo Red (CR) dye have been investigated. The adsorption capacities of CTS, MMT and CTS/MMT nanocomposite with CTS to MMT molar ratio of 5:1 for CR were compared. The results indicated that the adsorption capacity of CTS/MMT nanocomposite was higher than the mean values of those of CTS and MMT. The adsorption kinetics and isotherms were also studied. It was shown that all the sorption processes were better fitted by pseudo-second-order equation and the Langmuir equation. (C) 2007 Elsevier B.V. All rights reserved.

Keywords: Acid, Adsorbent, Adsorption, Adsorption Capacities, Adsorption Capacity, Adsorption Kinetics, Aqueous-Solutions, Biopolymer, Capacity, Characteristics, Chitosan, Chitosan, Clay Nanocomposites, Congo Red, Cr, CT, Dye, Dye Removal, Effects, FTIR, Isotherms, Kinetics, Langmuir, Langmuir Equation, Montmorillonite, Montmorillonite, Nanocomposite, Nanocomposites, pH, Pith, Pseudo Second Order, Pseudo-Second-Order, Sorption, Temperature, Value, Waste-Water, XRD

? Lee, C.K., Liu, S.S., Juang, L.C., Wang, C.C., Lin, K.S. and Lyu, M.D. (2007), Application of MCM-41 for dyes removal from wastewater. Journal of Hazardous Materials,