Personal Research Database

Full Text: 2010\J Haz Mat173, 487.pdf

Abstract: This study deals with the use of activated carbon prepared from bamboo waste (BMAC), as an adsorbent for the removal of chemical oxygen demand (COD) and color of cotton textile mill wastewater. Bamboo waste was used to prepare activated carbon by chemical activation using phosphoric acid (H3PO4) as chemical agent. The effects of three preparation variables activation temperature, activation time and H3PO4:precursor (wt%) impregnation ratio on the color and COD removal were investigated. Based on the central composite design (CCD) and quadratic models were developed to correlate the preparation variables to the color and COD. From the analysis of variance (ANOVA), the most influential factor on each experimental design response was identified. The optimum condition was obtained by using temperature of 556 degrees C, activation time of 2.33 h and chemical impregnation ratio of 5.24, which resulted in 93.08% of color and 73.98% of COD. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Adsorption, Analysis, Bamboo, Bamboo Waste, Chemical Activation, Chemical Oxygen Demand, COD, COD Removal, Color, Design, H₃PO₄, Methylene-Blue, Optimization, Removal, Response-Surface Methodology, Shell, Textile Wastewater, Wastewater

? Chakravarty, S., Mohanty, A., Sudha, T.N., Upadhyay, A.K., Konar, J., Sircar, J.K., Madhukar, A. and Gupta, K.K. (2010), Removal of Pb(II) ions from aqueous solution by adsorption using bael leaves (Aegle marmelos). Journal of Hazardous Materials, 173 (1-3), 502-509.

Full Text: 2010\J Haz Mat173, 502.pdf

Abstract: Biosorption of Pb(II) on bael leaves (Aegle marmelos) was investigated for the removal of Pb(II) from aqueous solution using different doses of adsorbent. initial pH, and contact time. The maximum Pb loading capacity of the bael leaves was 104 mg g^-1 at 50 mg L^-1 initial Pb(II) concentration at pH 5.1. SEM and FT-IR studies indicated that the adsorption of Pb(II) occurs inside the wall of the hollow tubes present in the bael leaves and carboxylic acid, thioester and sulphonamide groups are involved in the process. The sorption process was best described by pseudo second order kinetics. Among Freundlich and Langmuir isotherms, the latter had a better fit with the experimental data. The activation energy E-a confirmed that the nature of adsorption was physisorption. Bael leaves can selectively remove Pb(II) in the presence of other metal ions. This was demonstrated by removing Pb from the effluent of exhausted batteries. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Activation, Activation Energy, Adsorbent, Adsorption, Aegle Marmelos, Aqueous Solution, Biosorption, Biosorption, Capacity, Carboxylic, Concentration, Data, Energy, Equilibrium, Experimental, Fly-Ash, Freundlich, FT-IR, FTIR, FTIR Studies, Heavy-Metals, Ions, Isotherms, Kinetics, L1, Langmuir, Langmuir Isotherms, Lead Removal, Loading, Metal, Metal Ions, Pb, Pb(II), Pb(II) Ions, pH, Pseudo Second Order, Pseudo Second Order Kinetics, Pseudo-Second-Order, Removal, Rights, Sawdust, Second Order, Second Order Kinetics, Second-Order, SEM, Solution, Sorption, Sorption Process, Thermodynamics, Waste

? El-Menshawy, A.M., Kenawy, I.M. and El-Asmy, A.A. (2010), Modification of chloromethylated polystyrene with 2-mercabtobenzothiazole for application as a new sorbent for preconcentration and determination of Ag⁺ from different matrices. Journal of Hazardous Materials, 173 (1-3), 523-527.

Full Text: 2010\J Haz Mat173, 523.pdf

Abstract: Chloromethylated polystyrene polymer (CMSP) modified with 2-mercabtobenzothiazole (MBT) has been developed for the selective separation and/or preconcentration of silver. The modified polymer (CMS-MBT) was characterized by elemental analysis and IR spectra. Batch and column modes were applied. The newly designed polymer quantitatively sorbed Ag+ at pH 2 when the flow rate is 5 ml min(-1). The maximum sorption capacity was 0.493 mmol g(-1) while the preconcentration factor was 250 for Ag+. The detection limit was 8 ng ml(-1). The desorption was effective with 5 ml of 2 mol l(-1) HNO3 prior to detection using AAS. The modified polymer was highly ion-selective in nature even in the presence of large concentrations of electrolytes or organic media, with a preconcentrating ability for Ag+. The utility of the modified polymer to synthetic and drugs samples showed RSD values of <3% reflecting its accuracy and reproducibility. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: 2-Mercabtobenzothiazole, Absorption Spectrometric Determinations, Activated Carbon Column, Analysis, Atomic Emission-Spectrometry, Chelating Resin, Chloromethylated Polystyrene Polymer, Desorption, Environmental-Samples, Metal Ions, Modification, pH, Preconcentration, Separation, Solid-Phase Extraction, Sorbent, Sorption, Trace Amounts, Water Samples

? Lv, K.L., Yu, J.G., Deng, K.J., Sun, J., Zhao, Y.X., Du, D.Y. and Li, M. (2010), Synergistic effects of hollow structure and surface fluorination on the photocatalytic activity of titania. Journal of Hazardous Materials, 173 (1-3), 539-543.

Full Text: 2010\J Haz Mat173, 539.pdf

Abstract: To study the synergistic effects of hollow structure and surface fluorination on the photoactivity of TiO₂, TiO₂ hollow microspheres were synthesized by a hydrolysis-precipitate method using sulfonated polystyrene (PS) as templates and tetrabutylorthotitanate (TBOT) as precursor, and then calcined at 500 degrees C for 2 h. The calcined samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and N-2 sorption. Photocatalytic activity was evaluated using reactive brilliant red X3B, an anionic organic dye, as a model pollutant in water. The results show that the photocatalytic activity of TiO₂ hollow microspheres is significantly higher than that of TiO₂ nanoparticles prepared in the same experimental conditions. At pH 7 and 3, the apparent rate constants of the former exceed that of the latter by a factor of 3.38 and 3.15, respectively. After surface fluorination at pH 3, the photoactivity of hollow microspheres and nanoparticles further increases for another 1.61 and 2.19 times, respectively. The synergistic effect of surface fluorination and hollow structure can also be used to prepare other highly efficient photocatalyst. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Anatase, Degradation, Dye, Fluoride, Hollow Microsphere, Microspheres, Microstructures, Nanoparticles, Oxidation, pH, Phenol, Photocatalytic, Photocatalytic Activity, Photocatalytic Degradation, Rutile TiO₂, Sorption, Spheres, Surface Fluorination, TiO₂, TiO₂ Powders, Titania, Water, X-Ray, X-Ray Diffraction

? Venditti, F., Cuomo, F., Ceglie, A., Ambrosone, L. and Lopez, F. (2010), Effects of sulfate ions and slightly acidic pH conditions on Cr(VI) adsorption onto silica gelatin composite. Journal of Hazardous Materials, 173 (1-3), 552-557.

Full Text: 2010\J Haz Mat173, 552.pdf

Abstract: The feasibility of utilizing CTAB-silica gelatin composite (C-SGC) to remove hexavalent chromium from aqueous solutions under different conditions was investigated. Removal of chromate was assessed through evaluation of the adsorption kinetics of chromate ions on the composite under equilibrium conditions in the presence of sulfate ions and at a slightly acidic pH condition (pH 5.8). Adsorption competition tests in the presence of sulfate ions showed that Cr(VI) was still effectively adsorbed from aqueous solution regardless of the presence of the competing anions. In fact, the adsorption kinetics performed at different initial chromate concentrations were unaffected by the presence of 100 mg L-1 sulfate ions (pH 7.5). The equilibrium adsorption data were fitted by Freundlich adsorption isotherms which confirmed that the adsorption efficiency of chromium on the CTAB-silica gelatin composite was unchanged in the presence of sulfate ions. Further, the adsorption process was shown to be pH dependent and more efficient at slightly acidic pH (5.8). These findings demonstrated a high specificity of the CTAB-silica gelatin composite for chromium, and highlight the possibility of using this matrix for efficient removal of chromium from industrial wastewater without the need to eliminate contaminant sulfate ions. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Isotherms, Adsorption Kinetics, Aqueous Solutions, Aqueous-Solution, Chromate, Chromate, Chromium, Cr(VI), Cr(VI) Adsorption, CTAB, Equilibrium, Evaluation, Freundlich, Heavy-Metals, Hexavalent Chromium, Industrial Wastewater, Isotherm, Isotherms, Kinetics, Mechanism, Microemulsion, Microemulsion, Organogel, pH, Recovery, Removal, Silica, Sorption, Waste-Water, Wastewater

? Liu, S.Y., Gao, J., Yang, Y.J., Yang, Y.C. and Ye, Z.X. (2010), Adsorption intrinsic kinetics and isotherms of lead ions on steel slag. Journal of Hazardous Materials, 173 (1-3), 558-562.

Full Text: 2010\J Haz Mat173, 558.pdf

Abstract: Batch experiments were carried out to investigate the kinetics of adsorption of lead ions by steel slag on the basis of the external diffusion, intra-particle diffusion and adsorption reaction model (pseudo-first-order, pseudo-second-order). The results showed that the controlling step for the adsorption kinetics changed with the varying experimental parameters. When the particle size of steel slag was larger than 120 mesh, intra-particle diffusion of Pb(2+) was the controlling step, and when the initial concentration of Pb(2+) was less than 150 mg L(-1) or the shaking rate was lower than 150 rpm, external diffusion of Pb(2+) was promoted. Contrary to the former experimental conditions the adsorption reaction was the controlling step, and the adsorption followed second-order kinetics, with an adsorption rate constant of 13.26 g mg(-1) min(-1). The adsorption isotherm of Pb(2+) with steel slag followed the Langmuir model, with a correlation coefficient of 0.99. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Kinetics, Aqueous-Solution, Basic Dye, Biomass, Biosorption, Diffusion, Diffusion-Model, Heavy Metal, Ions, Isotherm, Isotherms, Kinetics, Langmuir Model, Lead, Metals, Model, Pseudo-First-Order, Pseudo-Second-Order, Rate Constant, Removal, Silica, Sorption, Sphagnum Moss Peat, Steel Slag

? Yuan, P., Liu, D., Fan, M.D., Yang, D., Zhu, R.L., Ge, F., Zhu, J.X. and He, H.P. (2010), Removal of hexavalent chromium [Cr(VI)] from aqueous solutions by the diatomite-supported/unsupported magnetite nanoparticles. Journal of Hazardous Materials, 173 (1-3), 614-621.

Full Text: 2010\J Haz Mat173, 614.pdf

Abstract: Diatomite-supported/unsupported magnetite nanoparticles were prepared by co-precipitation and hydrosol methods, and characterized by X-ray diffraction, nitrogen adsorption, elemental analysis, differential scanning calorimetry, transmission electron microscopy and X-ray photoelectron spectroscopy. The average sizes of the unsupported and supported magnetite nanoparticles are around 25 and 15 nm, respectively. The supported magnetite nanoparticles exist on the surface or inside the pores of diatom shells, with better dispersing and less coaggregation than the unsupported ones. The uptake of hexavalent chromium [Cr(VI)] on the synthesized magnetite nanoparticles was mainly governed by a physico-chemical process, which included an electrostatic attraction followed by a redox process in which Cr(VI) was reduced into trivalent chromium [Cr(III)]. The adsorption of Cr(VI) was highly pH-dependent and the kinetics of the adsorption followed a pseudo-second-order model. The adsorption data of diatomite-supported/unsupported magnetite fit well with the Langmuir isotherm equation. The supported magnetite showed a better adsorption capacity per unit mass of magnetite than unsupported magnetite, and was more thermally stable than their unsupported counterparts. These results indicate that the diatomite-supported/unsupported magnetite nanoparticles are readily prepared, enabling promising applications for the removal of Cr(VI) from aqueous solution. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Activated Carbons, Adsorption, Adsorption, Analysis, Capacity, Chromium, Co-Precipitation, Coprecipitation, Cr(VI), Diatom, Diatomite, Fly-Ash, Hexavalent, Hexavalent Chromium, Isotherm, Kinetics, Langmuir Isotherm, Magnetite, Metal Removal, Microscopy, Model, Nitrogen, Particles, Pseudo-Second-Order, Redox, Reduction, Removal, Shells, Sorption, Transmission Electron Microscopy, Trivalent Chromium, Uptake, Waste-Water, Zero-Valent Iron

? Safavi, A., Maleki, N. and Doroodmand, M.M. (2010), Fabrication of a selective mercury sensor based on the adsorption of cold vapor of mercury on carbon nanotubes: Determination of mercury in industrial wastewater. Journal of Hazardous Materials, 173 (1-3), 622-629.

Full Text: 2010\J Haz Mat173, 622.pdf

Abstract: A new sensor for the determination of mercury at mu g ml(-1) levels is proposed based on the adsorption of mercury vapor on single-walled carbon nanotubes (SWCNTs). The changes in the impedance of SWCNTs were monitored upon adsorption of mercury vapor. The adsorption behaviour of mercury on SWCNTs was compared with that on multi-walled carbon nanotubes (MWCNTs) and carbon nanofibers (CNFs). Cold vapor of mercury was generated at 65 degrees C using Sn(II) solution as a reducing agent. The limit of detection was 0.64 mu g ml(-1) for Hg(II) species. The calibration curve for Hg(II) was linear from 1.0 to 30.0 mu g ml(-1). The relative standard deviation (RSD) of eight replicate analyses of 15 mu g ml(-1) of Hg(II) was 2.7%. The results showed no interfering effects from many foreign species and hydride forming elements. The system was successfully applied to the determination of the mercury content of different types of wastewater samples. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Atomic-Absorption-Spectrometry, Capillary-Electrophoresis, Carbon Nanotubes, Cold Vapor, Determination, Flow-Injection System, Hg(II), High-Performance, Impedance, Industrial Wastewater, Inorganic Mercury, Marine Samples, Mercury Sensor, Methylmercury, Mwcnts, Sequential Injection, Solid-Phase Extraction, System, Trace Mercury, Wastewater

? Rodrigues, L.A., Maschio, L.J., da Silva, R.E. and da Silva, M.L.C.P. (2010), Adsorption of Cr(VI) from aqueous solution by hydrous zirconium oxide. Journal of Hazardous Materials, 173 (1-3), 630-636.

Full Text: 2010\J Haz Mat173, 630.pdf

Abstract: A type of ZrO(2)center dot nH(2)O Was synthesized and its Cr(VI) removal potential was investigated in this study. The kinetic study, adsorption isotherm, pH effect, thermodynamic study and desorption were examined in batch experiments. The kinetic process was described by a pseudo-second-order rate model very well. The Cr(VI) adsorption tended to increase with a decrease of pH. The adsorption data fitted well to the Langmuir model. The adsorption capacity increased from 61 to 66 mg g(-1) when the temperature was increased from 298 to 338 K. The positive values of both Delta H degrees and Delta S degrees suggest an endothermic reaction and increase in randomness at the solid-liquid interface during the adsorption. Delta G degrees values obtained were negative indicating a spontaneous adsorption process. The effective desorption of Cr(VI) on ZrO(2)center dot nH(2)O could be achieved using distilled water at pH 12. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Acid, Activated Carbon, Adsorption, Adsorption Isotherm, Capacity, Chromium, Chromium VI, Cr(VI), Cr(VI) Removal, Desorption, Hydrous Zirconium Oxide, Industrial Waste-Water, Ions, Isotherm, Kinetic, Langmuir Model, Model, pH, Phosphate, Precipitation, Pseudo-Second-Order, Removal, Thermodynamics, Titanium-Oxide

? Nibou, D., Mekatel, H., Amokrane, S., Barkat, M. and Trari, M. (2010), Adsorption of Zn²⁺ ions onto NaA and NaX zeolites: Kinetic, equilibrium and thermodynamic studies. Journal of Hazardous Materials, 173 (1-3), 637-646.

Full Text: 2010\J Haz Mat173, 637.pdf

Abstract: The adsorption of Zn(2+) onto NaA and NaX zeolites was investigated. The samples were synthesized according to a hydrothermal crystallization using aluminium isopropoxide (Al[OCH(CH(3))(2)](3)) as a new alumina source. The effects of pH, initial concentration, solid, liquid ratio and temperature were studied in batch experiments. The Freundlich and the Langmuir models were applied and the adsorption equilibrium followed Langmuir adsorption isotherm. The uptake distribution coefficient (K(d)) indicated that the Zn(2+) removal was the highest at minimum concentration. Thermodynamic parameters were calculated. The negative values of standard enthalpy of adsorption revealed the exothermic nature of the adsorption process whereas the negative activation entropies reflected that no significant change occurs in the internal structure of the zeolites solid matrix during the sorption of Zn(2+). The negative values of Gibbs free energy were indicative of the spontaneity of the adsorption process. Analysis of the kinetic and rate data revealed that the pseudo second-order sorption mechanism is predominant and the intra particle diffusion was the determining step for the sorption of zinc ions. The obtained optimal parameters have been applied to wastewater from the industrial zone (Algeria) in order to remove the contained zinc effluents. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Activation, Adsorption, Adsorption Equilibrium, Adsorption Isotherm, Aqueous-Solutions, Clinoptilolite, Diffusion, Energy, Equilibrium, Exchange, Gibbs Free Energy, Ions, Isotherm, Kinetic, Mechanism, Microporous Zeolite, Natural Zeolites, pH, Pseudo-Second-Order, Ratio, Removal, Selectivity, Sorption, Systems, Thermodynamic, Thermodynamic Parameters, Toluene, Uptake, Uranium, Wastewater, Zinc, Zinc (II) Ions, Zn²⁺

? Zhao, G.X., Zhang, H.X., Fan, Q.H., Ren, X.M., Li, J.X., Chen, Y.X. and Wang, X.K. (2010), Sorption of copper(II) onto super-adsorbent of bentonite-polyacrylamide composites. Journal of Hazardous Materials, 173 (1-3), 661-668.

Full Text: 2010\J Haz Mat173, 661.pdf

Abstract: In this work, bentonite embedded in the polyacrylamide (PAAm) gels was used as a novel adsorbent for the removal of Cu(II) from aqueous solution. The sorption and desorption of Cu(II) on bentonite-polyacrylamide (BENT-PAAm) was investigated as the function of pH, ionic strength, adsorbent content, Cu(II) concentrations and temperature. The results indicated that the sorption of Cu(II) on BENT-PAAm was strongly dependent on pH, ionic strength and temperature. The sorption increased from about 9% to 97% at pH ranging from 2.4 to 7. The sorption of Cu(II) on BENT-PAAm increased with increasing temperature and decreasing ionic strength. The sorption of Cu(II) on BENT and on BENT-PAAm was an endothermic and irreversible process. The results of desorption indicated that the adsorbed Cu(II) ions on solid particles were difficult to be desorbed from solid to liquid phase. From the comparison with BENT, BENT-PAAm showed higher sorption capacity with C-smax increasing from 29 to 33 mg/g at pH 6.2 and from 11 to 20 mg/g at pH 5.0 for the sorption of Cu(II) from BENT to BENT-PAAm composites. The average standard enthalpy change (Delta H degrees) and the entropy change (Delta S degrees) of Cu(II) sorption on BENT-PAAm are higher than those of Cu(II) sorption on BENT. The BENT-PAAm composites can be used as a super-adsorbent for the removal of Cu(II) from aqueous solution. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Aqueous-Solutions, Bentonite-Polyacrylamide, Chelating Resin, Copper(II), Cu(II), Desorption, Fulvic-Acid, Heavy-Metal Ions, MX-80 Bentonite, pH, Red Mud, Removal, Sorption, Super-Adsorbent, Thermodynamic Data

? Li, X.J., Liu, C.S., Li, F.B., Li, Y.T., Zhang, L.J., Liu, C.P. and Zhou, Y.Z. (2010), The oxidative transformation of sodium arsenite at the interface of alpha-MnO₂ and water. Journal of Hazardous Materials, 173 (1-3), 675-681.

Full Text: 2010\J Haz Mat173, 675.pdf

Abstract: Arsenite is acute contaminant to human health in soil and water environment. In this study, Pyrolusite (alpha-MnO2)was used to investigate the oxidative transformation of arsenite into arsenate with batch experiments under different reaction conditions. The results showed that arsenite transformation occurred and was accompanied by the adsorption and fixation of both As(III) and As(V) on alpha-MnO2. About 90% of sodium arsenite (10 mg/L) were transformed by alpha-MnO2 under the conditions of 25 degrees C and pH 6.0, 36.6% of which was adsorbed and 28.9% fixed by alpha-MnO2. Increased alpha-MnO2 dosages promoted As (III) transformation rate and adsorption of arsenic species. The transformation rate and adsorption of arsenic species raised with increasing pH values of reaction solution from 4.7 to 8.0. The oxidation rate decreased and adsorbed As(III) and As(V) increased with increasing initial arsenite concentration. The enhancement on oxidative transformation of sodium arsenite may result from abundant active sites of alpha-MnO2. Along with adsorption and fixation of arsenic species during the reaction, the crystal structure of alpha-MnO2 did not change, but the surface turned petty and loosen. Our results demonstrated that alpha-MnO2 has important potential in arsenic transformation and removal as the environmentally friendly natural oxidant in soil and surface water. (C) 2009 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Arsenate, Arsenate, Arsenic(III) Oxidation, Arsenite, As(V), Atomic Fluorescence Spectrometry, Batch, Kinetics, Manganese, Manganese Oxide, Nonchromatographic Speciation, Oxidation, Oxides, pH, Pyrolusite, Reductive Dissolution, Removal, Soil, Water

? Khokhotva, O. and Waara, S. (2010), The influence of dissolved organic carbon on sorption of heavy metals on urea-treated pine bark. Journal of Hazardous Materials, 173 (1-3), 689-696.

Full Text: 2010\J Haz Mat173, 689.pdf

Abstract: A previous study showed considerably higher metal adsorption by urea-treated pine bark (UTB) compared to non-treated bark (NTB) at metal adsorption from their individual relatively concentrated solutions. Comparison of the sorption characteristics of the two pine barks at low but environmentally relevant metal concentrations, and investigation of the influence of pH and dissolved organic carbon (DOC) on the sorption process are the aims of the present study. Sorption of Cu2+, Ni2+, Zn2+ and Pb2+ on pine bark of the species Pinus sylvestris was measured in multi-metal solutions in the presence and absence of DOC. In the absence of DOC, UTB gave lower residual metal concentrations (2-7 mu g/l for copper, 1-5 mu g/l for nickel, <0.05 mu g/l for zinc and lead) in the range of initial concentrations up to 0.7 mg/l, compared to NTB (6-15 mu g/l for copper, 2-24 mu g/l for nickel, 2-9 mu g/l for zinc, 2-3 mu g/l for lead). In the presence of DOC, sorption of Zn, Ni and Pb decreased by up to 75% depending on the DOC concentration. Metal sorption on UTB is less sensitive to pH and more adsorbed metal ions are retained compared to NTB. The potential use of urea-treated bark for treatment of waste water containing DOC and low concentrations of metals is discussed. (C) 2009 Published by Elsevier B.V.

Keywords: Adsorption, Cadmium, Copper, Desorption, Dissolved Organic Carbon, DOC, Enhanced Ultrafiltration, Heavy Metals, Humic-Acid, Ions, Landfill Leachate, Lead, Metal Adsorption, Metal Ions, Ni²⁺, Nickel, Pb²⁺, pH, Pinaster Bark, Pine Bark, Removal, Sewage-Sludge, Sorption, Treatment, Urea, Water, Water Treatment, Zinc

? Yin, P., Xu, Q., Qu, R.J., Zhao, G.F. and Sun, Y.Z. (2010), Adsorption of transition metal ions from aqueous solutions onto a novel silica gel matrix inorganic-organic composite material. Journal of Hazardous Materials,