Personal Research Database

Full Text: 2010\J Haz Mat179, 208.pdf

Abstract: The Langmuir two-site equation, X-ray photoelectron spectroscopy, and extended X-ray absorption fine structure spectroscopy have been employed to study the competitive behaviors of fluoride (F) and phosphate (P) in relation to arsenate adsorption on an Fe-Ce adsorbent as well as the mechanisms involved. The two-site isotherm revealed the presence of two kinds of adsorption sites with different binding affinities for arsenate. Both the total and low-binding-energy maximum adsorption capacities (Q and Q(1)) of arsenate decreased significantly even at a molar ratio of As/P = 1:0.1. The coexistence of F, only influenced the total Q of arsenate at high simultaneous F concentrations. The fact that Fe-Ce released 0.15-0.24 mmol sulfate for every mmol arsenate adsorbed suggested that, while sulfate groups might have played a role for adsorption, surface hydroxyl groups should be the major active sites. The XPS results indicated that arsenate and P are mainly adsorbed through the substitution of Fe surface active sites, while F is mainly adsorbed through substitution of Ce surface active sites. The As k-edge EXAFS data show that the second peak of Fe-Ce after arsenate adsorption is As-Fe shell, which further supported that arsenate adsorption occurs mainly at the Fe surface active sites. (c) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Arsenate, Arsenate Adsorption, Arsenic Removal, Arsenic(III), Competitive Adsorption, Exafs, Extended X-Ray Absorption Fine Structure Spectroscopy, F, Ferrihydrite, Fluoride, Interface, Isotherm, Langmuir, Mechanisms, Phosphate, Removal, Retention, Soils, Sorption, Stability, Water, X-Ray Photoelectron Spectroscopy, XPS

? Zhao, W.H., Sheng, N., Zhu, R., Wei, F.D., Cal, Z., Zhai, M.J., Du, S.H. and Hu, Q. (2010), Preparation of dummy template imprinted polymers at surface of silica microparticles for the selective extraction of trace bisphenol A from water samples. Journal of Hazardous Materials, 179 (1-3), 223-229.

Full Text: 2010\J Haz Mat179, 223.pdf

Abstract: Molecularly imprinted polymers for bisphenol A (BPA) were prepared by using surface molecular imprinting technique. Analogues of BPA, namely 4,4’-dihydroxybiphenyl and 3,3’,5,5’-tetrabromobisphenol A, were used as the dummy templates instead of BPA, to avoid the leakage of a trace amount of the target analyte (BPA). The resulting dummy molecularly imprinted polymers (DMIPs) showed the large sorption capacity, high recognition ability and fast binding kinetics for BPA. The maximal sorption capacity was up to 958 mu mol g(-1), and it only took 40 min for DMIPs to achieve the sorption equilibrium. The DMIPs were successfully applied to the solid-phase extraction coupled with HPLC/UV for the determination of BPA in water samples. The calibration graph of the analytical method was linear with a correlation coefficient more than 0.999 in the concentration range of 0.0760-0.912 ng mL(-1) of BPA. The limit of detection was 15.2 pg mL(-1) (S/N = 3). Recoveries were in the range of 92.9-102% with relative standard deviation (RSD) less than 11%. The trace amounts of BPA in tap water, drinking water, rain and leachate of one-off tableware were determined by the method built, and the satisfactory results were obtained. (c) 2010 Elsevier B.V. All rights reserved.

Keywords: Binding, Bpa, Drinking Water, Equilibrium, Kinetics, Liquid-Chromatography, Microspheres, Molecular Imprinted Polymers, Nanoparticles, Particles, Polymers, Preparation, Recognition, Removal, Silica, Solid-Phase Extraction, Solid-Phase Extraction, Sorbent, Sorption, Water, Water Sample

? Yan, L.G., Xu, Y.Y., Yu, H.Q., Xin, X.D., Wei, Q. and Du, B. (2010), Adsorption of phosphate from aqueous solution by hydroxy-aluminum, hydroxy-iron and hydroxy-iron-aluminum pillared bentonites. Journal of Hazardous Materials, 179 (1-3), 244-250.

Full Text: 2010\J Haz Mat179, 244.pdf

Abstract: Phosphorus removal is important for the control of eutrophication, and adsorption is an efficient treatment process. In this study, three modified inorganic-bentonites: hydroxy-aluminum pillared bentonite (Al-Bent), hydroxy-iron pillared bentonite (Fe-Bent), and mixed hydroxy-iron-aluminum pillared bentonite (Fe-Al-Bent), were prepared and characterized, and their phosphate adsorption capabilities were evaluated in batch experiments. The results showed a significant increase of interlayer spacing. BET surface area and total pore volume which were all beneficial to phosphate adsorption. Phosphate adsorption capacity followed the order: Al-Bent > Fe-Bent > Fe-Al-Bent. The adsorption rate of phosphate on the adsorbents fits pseudo-second-order kinetic models (R² = 1.00, 0.99, 1.00, respectively). The Freundlich and Langmuir models both described the adsorption isotherm data well. Thermodynamic studies illustrated that the adsorption process was endothermic and spontaneous in nature. Finally, phosphate adsorption on the inorganic pillared bentonites significantly raised the pH, indicating an anion/OH- exchange reaction. (c) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Isotherm, Adsorption Kinetics, Akaganeite, Fly-Ash, Furnace Slag, Isotherm, Kinetic, Kinetic Models, Langmuir, Mechanisms, Montmorillonite, Phosphate, Phosphorus, Pillared Bentonite, Simultaneous Removal, Simultaneous Sorption, Surfactant, Thermodynamic, Thermodynamics, Water

? Zhu, H.Y., Jiang, R., Xiao, L. and Li, W. (2010), A novel magnetically separable γ-Fe₂O₃/crosslinked chitosan adsorbent: Preparation, characterization and adsorption application for removal of hazardous azo dye. Journal of Hazardous Materials, 179 (1-3), 251-257.

Full Text: 2010\J Haz Mat179, 251.pdf

Abstract: A novel magnetically separable adsorbent, namely magnetic gamma-Fe2O3/crosslinked chitosan composites (M gamma-Fe₂O₃/CSCs), was prepared by miroemulsion process and characterized by XRD, FT-IR, TGA, DSC, SEM and VSM. Adsorption of methyl orange (MO), used as a model pollutant, from aqueous solution on M gamma-Fe₂O₃/CSCs was investigated. Characterization results indicated that magnetic gamma-Fe₂O₃ nanoparticles have been introduced in M gamma-Fe₂O₃/CSCs and kept intrinsic magnetic properties. The saturated magnetization (sigma(s)) of M gamma-Fe₂O₃/CSCs can be expediently adjusted by changing additive dosage of Fe₂O₃. Adsorption results showed that both nanocomposite adsorbents with weight ratio of gamma-Fe₂O₃ to chitosan of 1:10 and 2:5 exhibited higher adsorption capacities and attained adsorption equilibriums in shorter time compared with crosslinked chitosan. After adsorption, M gamma-Fe₂O₃/CSCs were effectively separated from reaction solution in 10 s by applying an adscititious magnetic field. Adsorption kinetics of MO on 1:10 M gamma-Fe2O3/CSCs followed the pseudo-second-order kinetic model. Effects of both initial pH and adsorbent dosage on the adsorption of MO were remarkable in experimental conditions. (c) 2010 Elsevier B.V. All rights reserved.

Keywords: Acid Dye, Adsorbent, Adsorption, Adsorption Kinetics, Aqueous-Solution, Carbon, Chitosan, Dye, Fe₃O₄-Chitosan Nanoparticles, Gamma-Fe₂O₃, Gamma- Fe₂O₃, Gas-Sensing Properties, Kinetic, Kinetics, Magnetic Separation, Methyl Orange, Methyl-Orange, Photocatalytic Degradation, Spent Activated Clay

? Li, Y.Z., Pan, H., Xu, J., Fan, X.W., Song, X.C., Zhang, Q., Xu, J. and Liu, Y. (2010), Characterization of metal removal by os sepiae of Sepiella maindroni Rochebrune from aqueous solutions. Journal of Hazardous Materials, 179 (1-3), 266-275.

Full Text: 2010\J Haz Mat179, 266.pdf

Abstract: To develop low cost metal adsorbents with less secondary pollution, metal adsorption from the aqueous solutions by the raw os sepiae (ROS) and alkali (NaOH)-pretreated OS (APOS) of the cuttlefish (Sepiella maindroni Rochebrune) was characterized. The capacities of adsorption of ROS and APOS were estimated to be 299.26 mg Cu g(-1) and 299.58 mg Cu g(-1), respectively. Metal adsorption by OS was significantly improved by appropriately increasing initial pH in the solution but hardly affected by temperature change within a wide range of 15-45 degrees C. Cu adsorption of both ROS and APOS was well described neither by Langmuir model nor by Freundlich model. Metal adsorption by OS fell in the order of Fe > Cu approximate to Cd > Zn in the solution with mixed metals, but followed the sequence of Cd > Cu > Fe Zn in the solutions respectively, with a single metal of Fe, Cu, Cd and Zn. The changes in Ca amounts in OS and solutions in adsorption strongly correlated with removal efficiencies of the metals. Obvious shifts of stretching bands of numbers of groups in OS after and before adsorption and the pretreatment occurred. It were concluded: (1) that metal adsorption by OS involves ion exchange, which occurred mainly between Ca rather than K and Na that OS itself contains and metals that were added in the solution, (2) that metal adsorption-promoting effects by NaOH pretreatment likely involve deprotonation of surface groups in OS, exposure of more functional groups, and increase in specific surface areas and (3) that related mechanisms for adsorption also likely include surface complexation, ectrostatic adsorption and even micro-deposition. The results also indicated that OS is a very promising absorbent for metal removal from electroplating wastewater. (c) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption, Aqueous Solution, Aqueous Solutions, Biomass, Biosorption, Characterization, Electroplating Wastewater, Freundlich, Heavy Metal, Heavy-Metals, Ion Exchange, Langmuir, Langmuir Model, Lead Ions, Low-Cost Adsorbents, Metal Adsorption, Metal Removal, OS Sepiae, pH, Pollution, Pretreatment, Removal, Saccharomyces-Cerevisiae, Shell, Wastewater, Water

? Khatibikamal, V., Torabian, A., Janpoor, F. and Hoshyaripour, G. (2010), Fluoride removal from industrial wastewater using electrocoagulation and its adsorption kinetics. Journal of Hazardous Materials, 179 (1-3), 276-280.

Full Text: 2010\J Haz Mat179, 276.pdf

Abstract: Electrocoagulation (EC) process using aluminum electrodes is proposed for removing fluoride from treated industrial wastewater originated from steel industry. Effects of different operating conditions such as temperature, pH, voltage, hydraulic retention time (HRT) and number of aluminum plates between anode and cathode plates on removal efficiency are investigated. Experimental results showed that by increasing HRT, removal efficiency increases but after 5 min changes are negligible. Therefore, the total HRT required is only 5 min. The more HRT, the more electrical current is needed in order to achieve to constant voltage and temperature in system. In addition, it is found that pH value decreases from 6.91 to 4.6 during first 10 min but it increases up to 9.5 during 50 min. After treatment, the fluoride concentration was reduced from initial 4.0-6.0 mg/L to lower than 0.5 mg/L. The pH of the influent is found as a very important variable which affects fluoride removal significantly. The optimal range for the influent is 6.0-7.0 at which not only effective defluoridation can be achieved, but also no pH readjustment is needed after treatment. Moreover, increasing number of aluminum plates between anode and cathode plates in bipolar system does not significantly affect fluoride removal. Finally, the kinetic analysis is done for the system which indicates that the adsorption system obeys the second-order kinetic model. (c) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Kinetic, Adsorption Kinetics, Aluminum, Analysis, Aqueous-Solution, Bipolar Aluminum Electrodes, Defluoridation, Electrocoagulation, Electrodialysis, Exchanger, Flotation, Fluoride, Fluoride Removal, Ground-Water, Hydraulic Retention Time, Industrial Wastewater, Industry, Ions, Kinetic, Kinetic Model, Kinetics, Model, pH, pH Value, Removal, Retention, Sahara Water, Sorbent, Treated Industrial Wastewater, Treatment, Wastewater

? Sun, X., Huang, X., Liao, X.P. and Shi, B. (2010), Adsorptive recovery of UO₂²⁺ from aqueous solutions using collagen-tannin resin. Journal of Hazardous Materials, 179 (1-3), 295-302.

Full Text: 2010\J Haz Mat179, 295.pdf

Abstract: Collagen-tannin resin (CTR), as a novel adsorbent, was prepared via reaction of collagen with black wattle tannin and aldehyde, and its adsorption properties to UO₂²⁺ were investigated in detail, including pH effect, adsorption kinetics, adsorption equilibrium and column adsorption kinetics. The adsorption of UO₂²⁺ on CTR was pH-dependent, and the optimal pH range was 5.0-6.0. CTR exhibited excellent adsorption capacity to UO₂²⁺. For instance, the adsorption capacity obtained at 303 K and pH 6.0 was as high as 0.91 mmol UO₂²⁺/g when the initial concentration of UO₂²⁺. was 1.0 mmol/L In kinetics studies, the adsorption equilibrium can be reached within 300 min, and the experimental data were well fitted by the pseudo-second-order rate model, and the equilibrium adsorption capacities calculated by the model were almost the same as those determined by experiments. The adsorption isotherms could be well described by the Freundlich equation with the correlation coefficients (R²) higher than 0.99, the adsorption behaviors of UO₂²⁺. on CTR column were investigated as well. Present study suggested that the CTR can be used for the adsorptive recovery of UO₂²⁺ from aqueous solutions. (c) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorbent, Adsorption, Adsorption Kinetics, Biosorption, Collagen-Tannin Resin, Column Adsorption, Equilibrium, Equilibrium Adsorption, Heavy-Metals, Immobilized Tannin, Ion-Exchange, Isotherms, Kinetics, Methylene-Blue, Precipitation, Removal, Sorption, Uranium, Uranium (UO₂²⁺)

? Kul, A.R. and Koyuncu, H. (2010), Adsorption of Pb(II) ions from aqueous solution by native and activated bentonite: Kinetic, equilibrium and thermodynamic study. Journal of Hazardous Materials, 179 (1-3), 332-339.

Full Text: 2010\J Haz Mat179, 332.pdf

Abstract: In this study, the adsorption kinetics, equilibrium and thermodynamics of Pb(II) ions on native (NB) and acid activated (AAB) bentonites were examined. The specific surface areas, pore size and pore-size distributions of the samples were fully characterized. The adsorption efficiency of Pb(II) onto the NB and AAB was increased with increasing temperature. The kinetics of adsorption of Pb(II) ions was discussed using three kinetic models, the pseudo-first-order, the pseudo-second-order and the intra-particle diffusion model. The experimental data fitted very well the pseudo-second-order kinetic model. The initial sorption rate and the activation energy were also calculated. The activation energy of the sorption was calculated as 16.51 and 13.66 kJ mol^-1 for NB and AAB, respectively. Experimental results were also analysed by the Langmuir, Freundlich and Dubinin-Redushkevich (D-R) isotherm equations at different temperatures. R-L separation factor for Langmuir and the n value for Freundlich isotherm show that Pb(II) ions are favorably adsorbed by NB and AAB. Thermodynamic quantities such as Gibbs free energy (G), the enthalpy (H) and the entropy change of sorption (S) were determined as about -5.06, 10.29 and 0.017 kJ mol^-1 K^-1, respectively for AAB. It was shown that the sorption processes were an endothermic reactions, controlled by physical mechanisms and spontaneously. (c) 2010 Elsevier B.V. All rights reserved.

Keywords: Activation Energy, Adsorbents, Adsorption, Adsorption Kinetics, Clay, Diffusion, Equilibrium, Freundlich Isotherm, Isotherm, Kaolinite, Kinetic, Kinetic Models, Kinetics, Langmuir, Lead, Metals, Montmorillonite, Pb(II), Pb(II) Ions, Perlite, Removal, Samples, Sorption, Thermodynamic

? Kantarli, I.C. and Yanik, J. (2010), Activated carbon from leather shaving wastes and its application in removal of toxic materials. Journal of Hazardous Materials, 179 (1-3), 348-356.

Full Text: 2010\J Haz Mat179, 348.pdf

Abstract: In this study, utilization of a solid waste as raw material for activated carbon production was investigated. For this purpose, activated carbons were produced from chromium and vegetable tanned leather shaving wastes by physical and chemical activation methods. A detailed analysis of the surface properties of the activated carbons including acidity, total surface area, extent of microporosity and mesoporosity was presented. The activated carbon produced from vegetable tanned leather shaving waste produced has a higher surface area and micropore volume than the activated carbon produced from chromium tanned leather shaving waste. The potential application of activated carbons obtained from vegetable tanned shavings as adsorbent for removal of water pollutants have been checked for phenol, methylene blue, and Cr(VI). Adsorption capacities of activated carbons were found to be comparable to that of activated carbons derived from biomass. (c) 2010 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Adsorption, Analysis, Aqueous-Solutions, Biomass, Chemical Activation, Chromium, Chromium Removal, Cr(VI), Leather Waste, Methylene Blue, Optimization, Phenol, Phenols, Phosphoric-Acid, Production, Removal, Surface-Chemistry, Water, Zinc-Chloride Activation

? Mohammad, M., Maitra, S., Ahmad, N., Bustam, A., Sen, T.K. and Dutta, B.K. (2010), Metal ion removal from aqueous solution using physic seed hull. Journal of Hazardous Materials, 179 (1-3), 363-372.

Full Text: 2010\J Haz Mat179, 363.pdf

Abstract: The potential of physic seed hull (PSH), Jantropha curcas L. as an adsorbent for the removal of Cd²⁺ and Zn²⁺ metal ions from aqueous solution has been investigated. It has been found that the amount of adsorption for both Cd²⁺ and Zn²⁺ increased with the increase in initial metal ions concentration, contact time, temperature, adsorbent dosage and the solution pH (in acidic range), but decreased with the increase in the particle size of the adsorbent. The adsorption process for both metal ions on PSH consists of three stages a rapid initial adsorption followed by a period of slower uptake of metal ions and virtually no uptake at the final stage. The kinetics of metal ions adsorption on PSH followed a pseudo-second-order model. The adsorption equilibrium data were fitted in the three adsorption isotherms-Freundlich, Langmuir and Dubinin-Radushkevich isotherms. The data best fit in the Langmuir isotherm indication monolayer chemisorption of the metal ions. The adsorption capacity of PSH for both Zn²⁺ and Cd²⁺ was found to be comparable with other available adsorbents. About 36-47% of the adsorbed metal could be leached out of the loaded PSH using 0.1 M HCI as the eluting medium. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorbent, Adsorbents, Adsorption, Adsorption-Kinetics, Cadmium, Cadmium (II), Copper, Equilibrium, Equilibrium Sorption, Heavy Metal, Heavy-Metals, Isotherm, Isotherms, Kinetics, Langmuir, Langmuir Isotherm, Lead, Physic Seed Hull, Waste, Zinc, Zinc (II)

? Jonsson, S., Lind, H., Lundstedt, S., Haglund, P. and Tysklind, M. (2010), Dioxin removal from contaminated soils by ethanol washing. Journal of Hazardous Materials, 179 (1-3), 393-399.

Full Text: 2010\J Haz Mat179, 393.pdf

Abstract: The aim of this study was to investigate the potential utility of ethanol washing for remediating soils contaminated with polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), as a cost-efficient alternative to conventional remediation methods of PCDD/F-contaminated soils. Initially, screening experiments were performed with a two-level full factorial design to examine the effects of temperature, extraction time and ethanol concentration on the removal efficiency. The screening experiments showed that the ethanol concentration was the most important parameter. In addition, repeated washing cycles considerably improved the results. Ethanol washing conditions were then selected (10 wash cycles with 75% ethanol at 60 degrees C), and applied to four soils with different soil characteristics and contamination levels to test the robustness of the selected method. Treatment efficiencies of 81% and 85% were obtained for a lightly contaminated sandy-silty soil and a highly contaminated clay soil rich in graphite particles, respectively. Even higher treatment efficiencies (>= 97%) were obtained for two other highly contaminated soils, one of which contained high amounts of organic matter. PCDD/Fs were found to both dissolve in the solvent and migrate into it as species adsorbed to particles. The relative contributions of these mechanisms and the overall efficiency of the removal seem to depend on contaminant concentration, the types of carbon in the soil matrix and the particle size distribution. The study shows that ethanol washing has effective remediation potential for a variety of PCDD/F-contaminated soils. (C) 2010 Published by Elsevier B.V.

Keywords: Clay, Desorption, Dibenzo-P-Dioxins, Mixtures, Particle-Size Separation, PCDD, PCDF, Pentachlorophenol, Pollutants, Polycyclic Aromatic-Hydrocarbons, Remediation, Removal, Soil, Soil Remediation, Soils, Solvent Washing, Solvent-Extraction, Sorption, Treatment, Water

? Unuabonah, E.I., Olu-Owolabi, B.I., Fasuyi, E.I. and Adebowale, K.O. (2010), Modeling of fixed-bed column studies for the adsorption of cadmium onto novel polymer-clay composite adsorbent. Journal of Hazardous Materials, 179 (1-3), 415-423.

Full Text: 2010\J Haz Mat179, 415.pdf

Abstract: Kaolinite clay was treated with polyvinyl alcohol to produce a novel water-stable composite called polymer-clay composite adsorbent. The modified adsorbent was found to have a maximum adsorption capacity of 20.400 +/- 13 mg/L (1236 mg/g) and a maximum adsorption rate constant of approximate to 7.45 x 10(-3) +/- 0.0002 L/(min mg) at 50% breakthrough. Increase in bed height increased both the breakpoint and exhaustion point of the polymer-clay composite adsorbent. The time for the movement of the Mass Transfer Zone (delta) down the column was found to increase with increasing bed height. The presence of preadsorbed electrolyte and regeneration were found to reduce this time. Increased initial Cd2+ concentration, presence of preadsorbed electrolyte, and regeneration of polymer-clay composite adsorbent reduced the volume of effluent treated. Premodification of polymer-clay composite adsorbent with Ca- and Na-electrolytes reduced the rate of adsorption of Cd2+ onto polymer-clay composite and lowered the breakthrough time of the adsorbent. Regeneration and re-adsorption studies on the polymer-clay composite adsorbent presented a decrease in the bed volume treated at both the breakpoint and exhaustion points of the regenerated bed. Experimental data were observed to show stronger fits to the Bed Depth Service Time (BDST) model than the Thomas model. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Capacity, Aqueous-Solution, Batch, Breakthrough, Cadmium, Cd²⁺, Clay, Fixed-Bed, Ions, Kaolinite, Lead, Mass Transfer, Model, Modeling, Modified Kaolinite Clay, Pb²⁺, Polymer-Clay Composite, Regeneration, Removal, Thomas Model, Waste

? Liu, H., Deng, S.B., Li, Z.J., Yu, G. and Huang, J. (2010), Preparation of Al-Ce hybrid adsorbent and its application for defluoridation of drinking water. Journal of Hazardous Materials,