Personal Research Database

Full Text: 2011\J Haz Mat190, 1009.pdf

Abstract: The adsorption of dimethyl sulfide from an aqueous solution by a cost-effective bamboo charcoal from Dendrocalamus was studied in comparison with other carbon adsorbents. The bamboo charcoal exhibited superior adsorption on dimethyl sulfide compared with powdered activated carbons at different adsorbent dosages. The adsorption characteristics of dimethyl sulfide onto bamboo charcoal were investigated under varying experimental conditions such as particle size, contact time, initial concentration and adsorbent dosage. The dimethyl sulfide removal was enhanced from 31 to 63% as the particle size was decreased from 24-40 to >300 mesh for the bamboo charcoal. The removal efficiency increased with increasing the adsorbent dosage from 0.5 to 10 mg, and reached 70% removal efficiency at 10 mg adsorbed. The adsorption capacity (mu g/g) increased with increasing concentration of dimethyl sulfide while the removal efficiency decreased. The adsorption process conforms well to a pseudo-second-order kinetics model. The adsorption of dimethyl sulfide is more appropriately described by the Freundlich isotherm (R², 0.9926) than by the Langmuir isotherm (R², 0.8685). Bamboo charcoal was characterized by various analytical methods to understand the adsorption mechanism. Bamboo charcoal is abundant in acidic and alcohol functional groups normally not observed in PAC. A distinct difference is that the superior mineral composition of Fe (0.4 wt%) and Mn (0.6 wt%) was detected in bamboo charcoal elements not found in PAC. Acidic functional group and specific adsorption sites would be responsible for the strong adsorption of dimethyl sulfide onto bamboo charcoal of Dendrocalamus origin. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: 2-Methylisoborneol, Activated Carbon, Adsorption, Alcohol, Bamboo Charcoal, Drinking-Water, Geosmin, Isotherm, Kinetics, Langmuir Isotherm, Methyl Sulfide, Mib, Model, Odor, Odorant, Pseudo-Second-Order, Removal

? Chen, Y.L., Pan, B.C., Zhang, S.J., Li, H.Y., Lv, L. and Zhang, W.M. (2011), Immobilization of polyethylenimine nanoclusters onto a cation exchange resin through self-crosslinking for selective Cu(II) removal. Journal of Hazardous Materials, 190 (1-3), 1037-1044.

Full Text: 2011\J Haz Mat190, 1037.pdf

Abstract: Donnan membrane principle provides great opportunities for development of highly efficient adsorbents for toxic metals abatement. Based on the principle we prepared a new composite adsorbent by immobilizing polyethylenimine (PEI) nanoclusters within a macroporous cation exchanger D001 through self-crosslinking by glutaraldehyde upon Cu(II)-template process. Negligible PEI loss was observed from the resultant composite adsorbent D001-PEI-GA to solution of pHs 1-12. Increasing solution pH from 1 to 6 results in more favorable Cu(II) retention by D001-PEI-GA, and Cu(II) adsorption onto D001-PEI-GA follows the pseudo-second-order kinetic model well. Compared to D001, D001-PEI-GA displays more preferable Cu(II) sequestration in the presence of co-ions Mg²⁺, Ca²⁺, Sr²⁺ at higher levels. Fixed-bed adsorption of a synthetic solution containing Cu(II) and other co-ions showed that Cu(II) sequestration on D001-PEI-GA could result in its conspicuous decrease from 5 mg/L to below 0.01 mg/L with the treatment volume as high as 630 BV per run, while that for 0001 was only similar to 85 BV. Also, the spent composite adsorbent can be readily regenerated by HCl (0.3 M)-NaCl (0.5 M) binary solution for repeated use with negligible capacity loss. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Aqueous-Solutions, Beads, Cation Exchange, Chelating Adsorption Properties, Composite Adsorbent, Cu(II), Development, Fast Kinetics, Gel, Heavy Metals, Heavy-Metal Ions, High-Capacity, Ion Exchanger, Model, PEI, pH, Poly(Glycidyl Methacrylate), Polyethylenimine, Pseudo-Second-Order, Selectivity, Sorption, Synthetic Solution

? Shi, Y.J., Wang, X.H., Qi, Z., Diao, M.H., Gao, M.M., Xing, S.F., Wang, S.G. and Zhao, X.C. (2011), Sorption and biodegradation of tetracycline by nitrifying granules and the toxicity of tetracycline on granules. Journal of Hazardous Materials, 191 (1-3), 103-109.

Full Text: 2011\J Haz Mat191, 103.pdf

Abstract: This paper examines the simultaneous sorption and biodegradation performance of tetracycline (TC) by the nitrifying granular sludge as well as the short-term exposure toxicity of TC. The removal of TC was characterized by a quick sorption and a slow process of biodegradation. The adsorption process fits pseudo-second-order kinetic model, with a complex mechanism of surface adsorption and intra-particle diffusion. Both temperature and mixed liquor suspended solid (MLSS) influenced TC sorption to the granules. TC biodegradation was enhanced with the increase of COD and NH(4)(+)-N concentrations, with except of the NH(4)(+)-N concentrations higher than 150 mg/L. With the ATU addition, TC degradation was weakened remarkably, indicating a synergistic effect of multiple microbes. Results of the short-term exposure (12 h) effects showed that the respirometric activities of the microbes decreased greatly. The addition of TC also decreased the rate of NH(4)(+)-N utilization considerably, with the half saturation constant (K(s)) increasing from 297.7 to 347.2 mg/L. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated-Sludge Process, Adsorption, Aerobic Granules, Antibiotics, Biodegradation, Degradation, Diffusion, Kinetic, Kinetic Model, Kinetics, Manure, Mechanism, Nitrification, Nitrifying Granular Sludge, Pharmaceuticals, Removal, Sorption, Temperature, Tetracycline, Toxicity, Waste-Water Treatment

? Zhang, Y.L., Wong, J.W.C., Liu, P.H. and Yuan, M. (2011), Heterogeneous photocatalytic degradation of phenanthrene in surfactant solution containing TiO₂ particles. Journal of Hazardous Materials, 191 (1-3), 136-143.

Full Text: 2011\J Haz Mat191, 136.pdf

Abstract: Photocatalytic degradation of phenanthrene (PHE) over TiO₂ in aqueous solution containing nonionic surfactant micelles was investigated. All photocatalytic experiments were conducted using a 253.7 nm mercury monochromatic ultraviolet lamp in a photocatalytic reactor. The surfactant micelles could provide a nonaqueous “cage” to result in a higher degradation rate of PHE than in an aqueous solution, but the higher Triton X-100 concentration (more than 2 g/L) lowered the degradation ratio of PHE because the additional surfactant micelles hindered the movement of micelles containing PHE so as to reduce their adsorption onto titania. Pseudo-second-order kinetics was observed for the photocatalytic degradation of PHE. Alkaline solution environment was beneficial to the photocatalytic degradation of PHE. PHE degradation could mainly be attributed to the formation of hydroxyl radicals as evident from the comparison of degradation efficiencies when O₂, H₂O₂ and tert-butyl alcohol (TBA) were applied as oxidants or hydroxyl radical scavenger. Based on the GC/MS analysis of the intermediates, the possible pathways of the photocatalytic degradation of PHE were proposed. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Alkaline 2-Propanol, Aqueous Solution, Aroclor 1254, Degradation Pathway, Kinetics, Mercury, Oxidation, Phenanthrene, Photocatalytic Degradation, Photochemistry, Photodechlorination, Photodegradation, Pseudo-Second-Order Kinetics, Pyrene, Soil Surfaces, Surfactant, Visible-Light Irradiation, Water

? Wahab, M.A., Ben Hassine, R. and Jellali, S. (2011), Posidonia oceanica (L.) fibers as a potential low-cost adsorbent for the removal and recovery of orthophosphate. Journal of Hazardous Materials, 191 (1-3), 333-341.

Full Text: 2011\J Haz Mat191, 333.pdf

Abstract: Adsorption efficiency of orthophosphate from aqueous solution onto Posidonia oceanica fibers (POF) as a raw, natural and abundant material was investigated and compared with other common natural materials. A series of batch tests were undertaken to assess the effect of the system variables, i.e. initial aqueous orthophosphate concentration, contact time, adsorbent dosage, pH and temperature. Results indicate that orthophosphate uptake increased with increasing initial orthophosphate concentration, temperature and adsorbent dosage and decreased with increasing pH values. The maximum adsorption capacity (Q(m)) determined from the Langmuir isotherm was calculated to be 7.45 mg g^-1 for the studied orthophosphates concentration range of 15-100 mg L^-1, pH 7; adsorbent dosage of 2 g L^-1 and temperature of 20±2ºC. The adsorption data were very well described by the pseudo-second order model predicting a chemisorption process. The energy dispersive spectroscopy (EDS) and FIR analysis before and after adsorption of orthophosphate onto POF showed that the main involved mechanisms are ligand exchange between orthophosphate and Cl^-, SO₄^2- and OH^-and precipitation with calcium. In comparison with other natural adsorbents, raw POF could be considered as one of the most efficient natural materials for the removal of orthophosphate with the possibility of agronomic reuse. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorbent, Adsorption, Adsorption Efficiency, Adsorption Mechanisms, Aqueous Solution, Aqueous-Solution, Biosorption, Calcium, Constructed Wetland Systems, Filter Medium, Fly-Ash, Isotherm, Langmuir, Langmuir Isotherm, Low-Cost Adsorbent, Media, Modeling, Orthophosphate, pH, Phosphate Adsorption, Phosphorus Retention, Pof, Posidonia Oceanica, Recovery, Removal, Shell Sand, Temperature, Uptake, Waste-Water Treatment

? Chen, H., Zhao, J., Wu, J.Y. and Dai, G.L. (2011), Isotherm, thermodynamic, kinetics and adsorption mechanism studies of methyl orange by surfactant modified silkworm exuviae. Journal of Hazardous Materials, 192 (1), 246-254.

Full Text: 2011\J Haz Mat192, 246.pdf

Abstract: This paper reports on the development of organo-modified silkworm exuviae (MSE) adsorbent prepared by using hexadecyltrimethylammonium bromide (HDTMAB) for removing methyl orange (MO), a model anionic dye, from aqueous solution. The natural and modified samples were characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscopy (FT-IR). Batch adsorption experiments were carried out to remove MO from its aqueous solutions using SE and MSE. It was observed that the adsorption capacity of MSE is 5-6 times of SE. The different parameters effecting on the adsorption capacity such as pH of the solution, initial dye concentration, temperature and contact time have been investigated. Analysis of adsorption results obtained at different temperatures showed that the adsorption pattern on the MSE can be described perfectly with Langmuir isotherm model compared with Freundlich and Dubinin-Radushkevich (D-R) isotherm models, and the characteristic parameters for each adsorption isotherm were also determined. The adsorption process has been found exothermic in nature and thermodynamic parameters have been calculated. The adsorption kinetic followed the pseudo-second order kinetic model. The results of FT-IR, EDS and desorption studies all suggest that methyl orange adsorption onto the MSE should be mainly controlled by the hydrophobic interaction mechanism, along with a considerable contribution of the anionic exchange mechanism. The results indicate that HDTMAB-modified silkworm exuviae could be employed as low-cost material for the removal of methyl orange anionic dye from wastewater. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Acid Dye, Adsorbent, Adsorption, Adsorption Isotherm, Anionic Dye, Aqueous Solution, Aqueous-Solution, Batch, Batch Adsorption, Cationic Surfactant, Desorption, Dye, Dye Removal, Freundlich, FT-IR, FTIR, Isotherm, Kinetic, Kinetic Model, Kinetics, Langmuir, Langmuir Isotherm, Leaf Powder, Low-Cost Adsorbents, Malachite-Green, Mechanism, Methyl Orange, Natural Clinoptilolite, P-Nitrophenol, pH, Removal, SEM, Silkworm Exuviae, Surface Modification, Temperature, Thermodynamic, Thermodynamic Parameters, Wastewater

? Li, G.L., Zhao, Z.S., Liu, J.Y. and Jiang, G.B. (2011), Effective heavy metal removal from aqueous systems by thiol functionalized magnetic mesoporous silica. Journal of Hazardous Materials, 192 (1), 277-283.

Full Text: 2011\J Haz Mat192, 277.pdf

Abstract: A thiol-functionalized magnetic mesoporous silica material (called SH-mSi@Fe₃O₄), synthesized by a modified Stober method, has been investigated as a convenient and effective adsorbent for heavy metal ions. Structural characterization by powder X-ray diffraction, N₂ adsorption-desorption isotherm. Fourier transform infrared spectroscopy and elemental analyses confirms the mesoporous structure and the organic moiety content of this adsorbent. The high saturation magnetization (38.4 emu, g) make it easier and faster to be separated from water under a moderate magnetic field. Adsorption kinetics was elucidated by pseudo-second-order kinetic equation and exhibited 3-stage intraparticle diffusion mode. Adsorption isotherms of Hg and Pb fitted well with Langmuir model, exhibiting high adsorption capacity of 260 and 91.5 mg of metal, g of adsorbent, respectively. The distribution coefficients of the tested metal ions between SH-mSi@Fe₃O₄ and different natural water sources (groundwater, lake water, tap water and river water) were above the level of 10(5) mL, g. The material was very stable in different water matrices, even in strong acid and alkaline solutions. Metal-loaded SH-mSi@Fe₃O₄ was able to regenerate in acid solution under ultrasonication. This novel SH-mSi@Fe₃O₄ is suitable for repeated use in heavy metal removal from different water matrices. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated Carbons, Adsorbent, Adsorption, Adsorption Isotherms, Adsorption Kinetics, Characterization, Clinoptilolite, Diffusion, Distribution Coefficients, Drinking-Water, Heavy Metal, Hg(II), Ions, Isotherm, Isotherms, Kinetic, Kinetics, Langmuir, Magnetism, Mesoporous Silica, Microspheres, Nanoparticles, Organosilicas, Pb, Polysilsesquioxanes, Removal, Selective Adsorption, Silica, Thiol Functionalization, Water, X-Ray Diffraction

? Khan, S.S., Srivatsan, P., Vaishnavi, N., Mukherjee, A. and Chandrasekaran, N. (2011), Interaction of silver nanoparticles (SNPs) with bacterial extracellular proteins (ECPs) and its adsorption isotherms and kinetics. Journal of Hazardous Materials, 192 (1), 299-306.

Full Text: 2011\J Haz Mat192, 299.pdf

Abstract: Indiscriminate and increased use of silver nanoparticles (SNPs) in consumer products leads to the release of it into the environment. The fate and transport of SNPs in environment remains unknown. We have studied the interaction of SNPs with extracellular protein (ECP) produced by two environmental bacterial species and the adsorption behavior in aqueous solutions. The effect of pH and salt concentrations on the adsorption was also investigated. The adsorption process was found to be dependent on surface charge (zeta potential). The capping of SNPs by ECP was confirmed by Fourier transform infrared spectroscopy and X-ray diffraction. The adsorption of ECP on SNPs was analyzed by Langmuir and Freundlich models, suggesting that the equilibrium adsorption data fitted well with Freundlich model. The equilibrium adsorption data were modeled using the pseudo-first-order and pseudo-second-order kinetic equations. The results indicated that pseudo-second-order kinetic equation would better describe the adsorption kinetics. The capping was stable at environmental pH and salt concentration. The destabilization of nanoparticles was observed at alkaline pH. The study suggests that the stabilization of nanoparticles in the environment might lead to the accumulation and transport of nanomaterials in the environment, and ultimately destabilizes the functioning of the ecosystem. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Isotherms, Adsorption Kinetics, Behavior, Cells, Consumer, Cytotoxicity, Enhanced Raman-Spectroscopy, Environment, Environmental, Equilibrium, Exposure, Extracellular Protein, Isotherms, Kinetic, Kinetic Equations, Kinetics, Langmuir and Freundlich Models, Lead, Model, Nanotechnology, pH, Pseudo-First-Order, Pseudo-Second-Order, Silver Nanoparticles, Sorption, Surface, Surface Charge, Zeta Potential

? Tseng, H.H., Su, J.G. and Liang, C.J. (2011), Synthesis of granular activated carbon/zero valent iron composites for simultaneous adsorption/dechlorination of trichloroethylene. Journal of Hazardous Materials, 192 (2), 500-506.

Full Text: 2011\J Haz Mat192, 500.pdf

Abstract: The coupling adsorption and degradation of trichloroethylene (ICE) through dechlorination using synthetic granular activated carbon and zerovalent iron (GAC-ZVI) composites was studied. The GAC-ZVI composites were prepared from aqueous Fe(2+) solutions by impregnation with and without the use of a PEG dispersant and then heated at 105 degrees C or 700 degrees C under a stream of N(2). Pseudo-first-order rate constant data on the removal of TCE demonstrates that the adsorption kinetics of GAC is similar to those of GAC-ZVI composites. However, the usage of GAC-ZVI composites liberated a greater amount of Cl than when ZVI was used alone. The highest degree of reductive dechlorination of TCE was achieved using a GAC-ZV1700P composite (synthesized using PEG under 700 degrees C). A modified Langmuir-Hinshelwood rate law was employed to depict the behavior of Cl liberation. As a result, a zero-order Cl liberation reaction was observed and the desorption limited TCE degradation rate constant decreased as the composite dosage was increased. The GAC-ZVI composites can be employed as a reactive GAC that is not subject to the limitations of using GAC and ZVI separately. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Adsorption Kinetics, Behavior, Chlorinated Solvent, Desorption, Fe-O, GAC, Granular Activated Carbon, Groundwater Remediation, Iron, Kinetics, Modified, Nanoparticles, Nanoscale Zerovalent Iron, Particles, Pseudo-First-Order, Rate Constant, Reactive Activated Carbon, Reactivity, Reduction, Reductive Dehalogenation, Remediation, Removal, Synthesis, TCE, TCE Dechlorination, Trichloroethylene, Waste Water Treatment, Zerovalent Iron

? Hu, K.S., Xiao, X., Cao, X.F., Hao, R., Zuo, X.X., Zhang, X.J. and Nan, J.M. (2011), Adsorptive separation and photocatalytic degradation of methylene blue dye on titanate nanotube powders prepared by hydrothermal process using metal Ti particles as a precursor. Journal of Hazardous Materials, 192 (2), 514-520.

Full Text: 2011\J Haz Mat192, 514.pdf

Abstract: Titanate nanotube powders (TNTPs) with the twofold removal ability, i.e. adsorptive separation and photocatalytic degradation, are synthesized under hydrothermal conditions using metal Ti particles as a precursor in the concentrated alkaline solution, and their morphology, structure, adsorptive and photocatalytic properties are investigated. Under hydrothermal conditions, the titanate nanotubes (TNTs) with pore diameter of 3-4 nm are produced on the surface of metal Ti particles, and stacked together to form three-dimensional (3D) network with porous structure. The TNTPs synthesized in the autoclave at 130ºC for 24h exhibits a maximum adsorption capability of about 197 mg g^-1 in the neutral methylene blue (MB) solution (40 mg L^-1) within 90 min, the adsorption process can be described by pseudo second-order kinetics model. Especially, in comparison with the adsorptive and the photocatalytic processes are performed in turn, about 50 min can be saved through synchronously utilizing the double removal ability of TNTPs when the removal ratio of MB approaches 95% in MB solution (40 mg L^-1) at a solid-liquid (S, L) ratio of 1:8 under ultraviolet (UV) light irradiation. These 3D TNTPs with the twofold removal properties and easier separation ability for recycling use show promising prospect for the treatment of dye pollutants from wastewaters in future industrial application. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Anatase, Dye, Dye Pollutants, Facets, Hydrolysis, Hydrothermal Method, Irradiation, Kinetics, Metal Ti, Methylene Blue, Nanoparticles, Photocatalytic Activity, Removal, Separation, Titanate Nanotube

? Panda, L., Das, B., Rao, D.S. and Mishra, B.K. (2011), Application of dolochar in the removal of cadmium and hexavalent chromium ions from aqueous solutions. Journal of Hazardous Materials, 192 (2), 822-831.

Full Text: 2011\J Haz Mat192, 822.pdf

Abstract: Dolochar, a waste material generated in sponge iron industry, is processed and put to test as an adsorbent for removal of Cd(II) and Cr(VI) ions from aqueous solutions. The dolochar samples were characterised to determine the different phases and their distribution by reflection microscopy. The analysis indicated that the sample consists of metallic iron, fused carbon, and Ca-Mg bearing phases (Ca-Mg-silicate-oxide) along with lots of voids and pores. The fixed carbon (FC) content of the material is 13.8% with a Langmuir surface area of 81.6 m(2), g and micropore area of 34.1 m(2), g. Batch adsorption experiments have been conducted to study the sorption behaviour of Cd(II) and Cr(VI) ions on dolochar as a function of particle size, contact time, adsorbent dosages, pH and temperature. It is observed that higher pH and temperature enhances sorption of Cd(II) ions. In contrast, the adsorption for Cr(VI) is found to be better in acidic pH in comparison to alkaline media. The equilibrium adsorption isotherm data are tested by applying both Langmuir and Freundlich isotherm models. It is observed that Langmuir isotherm model fitted better compared to the Freundlich model indicating monolayer adsorption. The thermodynamic parameters such as ΔG degrees, ΔHº and ΔSº indicate the effectiveness of dolochar to remove Cd(II) and Cr(VI) ions from aqueous solution. The kinetics of adsorption is found to better fit to pseudo second order reaction. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorbent, Adsorption, Adsorption, Adsorption Isotherm, Agricultural Waste Material, Aqueous Solution, Batch, Batch Adsorption, Cadmium, Cd(II), Chromium, Cr(VI), Dolochar, Effluents, Equilibrium, Freundlich, Freundlich Isotherm, Heavy-Metals Removal, Hexava Lent Chromium, Isotherm, Kinetics, Langmuir, Langmuir Isotherm, Low-Cost Adsorbents, pH, Removal, Rice Husk, Sorption, Temperature, Thermodynamic, Thermodynamic Parameters, Trivalent, Waste

? Luo, X.B., Luo, S.L., Zhan, Y.C., Shu, H.Y., Huang, Y.N. and Tu, X.M. (2011), Novel Cu(II) magnetic ion imprinted materials prepared by surface imprinted technique combined with a sol-gel process. Journal of Hazardous Materials, 192 (3), 949-955.

Full Text: 2011\J Haz Mat192, 949.pdf

Abstract: A novel Cu (II) magnetic ion-imprinted polymer (MIIP) was synthesized by surface imprinting technique combined with a sol-gel process. The adsorbent of Cu (II)-MIIP shows higher capacity and selectivity than that of magnetic non-imprinted polymers (MNIP). Adsorption capacities of Cu (II)-MIIP and MNIP are 24.2 and 5.2 mg/g for Cu (II) ions, respectively. The selectivity coefficients of the Cu (II)-MIIP for Cu (II)/Zn (II) and Cu (II)/Ni (II) are 91.84 and 133.92, respectively. Kinetics studies show that the adsorption process obeys pseudo-second-order rate mechanism with an initial adsorption rate of 132.48 for Cu (II)-MIIP and 2.41 mg g^-1 min^-1 for MNIP. In addition, no obvious decrease was observed after up to five adsorption cycles, indicating that the Cu (II)-MIIP is of high stability. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorbent, Adsorption, Aqueous-Solutions, Beads, Composite Adsorbent, Cu(II), Cu(II), Heavy-Metal Ions, Kinetics, Magnetic Ion Imprinted Polymer, Mechanism, Nanoparticles, Particles, Polymer, Pseudo Second Order, Selective Removal, Selectivity, Sol-Gel, Sol-Gel Process, Surface Imprinted Technique

? Zhang, D., Niu, H.Y., Zhang, X.L., Meng, Z.F. and Cai, Y.Q. (2011), Strong adsorption of chlorotetracycline on magnetite nanoparticles. Journal of Hazardous Materials, 192 (3), 1088-1093.

Full Text: 2011\J Haz Mat192, 1088.pdf

Abstract: In this work, environmentally friendly magnetite nanoparticles (Fe₃O₄ MNPs) were used to adsorb chlorotetracycline (CTC) from aqueous media. Fe₃O₄ MNPs exhibit ultrahigh adsorption ability to this widely used antibiotic. The adsorption behavior of CTC on Fe₃O₄ MNPs fitted the pseudo-second-order kinetics model, and the adsorption equilibrium was achieved within 10 h. The maximum Langmuir adsorption capacity of CTC on Fe₃O₄ (476 mg g(-1)) was obtained at pH 6.5. Thermodynamic parameters calculated from the adsorption data at different temperature showed that the adsorption reaction was endothermic and spontaneous. Low concentration of NaCl and foreign divalent cations hardly affected the adsorption. Negative effect of coexisting humic acid (HA) on CTC adsorption was also observed when the concentration of HA was lower than 20 mg L(-1). But high concentration of HA (>20 mg L(-1)) increased the CTC adsorption on Fe₃O₄ MNPs. The matrix effect of several environmental water samples on CTC adsorption was not evident. Fe₃O₄ MNPs were regenerated by treatment with H(2)O(2) or calcination at 400º C in N(2) atmosphere after separation from water solution by an external magnet. This research provided a high efficient and reusable adsorbent to remove CTC selectively from aqueous media. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated-Sludge, Adsorbent, Adsorption, Antibiotics, Cations, Chlorotetracycline, Constants, Equilibrium, Fe₃O₄ Nanoparticles, Humic Acid, Humic-Acid, Kinetics, Langmuir, Oxides, pH, Pseudo Second Order, Regeneration, Removal, Separation, Soils, Sorption, Temperature, Tetracycline Resistance Genes, Thermodynamic, Thermodynamic Parameters, Waste-Water, Water

? Zhou, J.B., Yang, S.L., Yu, J.G. and Shu, Z. (2011), Novel hollow microspheres of hierarchical zinc-aluminum layered double hydroxides and their enhanced adsorption capacity for phosphate in water. Journal of Hazardous Materials, 192 (3), 1114-1121.

Full Text: 2011\J Haz Mat192, 1114.pdf

Abstract: Hollow microspheres of hierarchical Zn-Al layered double hydroxides (LDHs) were synthesized by a simple hydrothermal method using urea as precipitating agent. The morphology and microstructure of the as-prepared samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), nitrogen adsorption-desorption isotherms and fourier transform infrared (FTIR) spectroscopy. It was found that the morphology of hierarchical Zn-Al LDHs can be tuned from irregular platelets to hollow microspheres by simply varying concentrations of urea. The effects of initial phosphate concentration and contact time on phosphate adsorption using various Zn-Al LDHs and their calcined products (LDOs) were investigated from batch tests. Our results indicate that the equilibrium adsorption data were best fitted by Langmuir isothermal model, with the maximum adsorption capacity of 54.1-232 mg/g: adsorption kinetics follows the pseudo-second-order kinetic equation and intra-particle diffusion model. In addition, Zn-Al LDOs are shown to be effective adsorbents for removing phosphate from aqueous solutions due to their hierarchical porous structures and high specific surface areas. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Adsorption Isotherm, Adsorption Kinetics, Aqueous-Solution, Diffusion, Electron Microscopy, Equilibrium, Fly-Ash, FTIR, Furnace Slag, Hierarchical Porous Structures, Hollow Microspheres, Iron, Isotherms, Kinetic, Kinetics, Langmuir, Layered Double Hydroxides, Macro-, Mesoporous Titania, Phosphate, Phosphate Adsorption, Phosphorus Removal, Photocatalytic Activity, Pseudo Second Order, Template-Free Fabrication, Waste-Water, Water, X-Ray Diffraction, Zn-Al LDHS

? Machado, F.M., Bergmann, C.P., Fernandes, T.H.M., Lima, E.C., Royer, B., Calvete, T. and Fagan, S.B. (2011), Adsorption of Reactive Red M-2BE dye from water solutions by multi-walled carbon nanotubes and activated carbon. Journal of Hazardous Materials, 192 (3), 1122-1131.

Full Text: 2011\J Haz Mat192, 1122.pdf

Abstract: Multi-walled carbon nanotubes and powdered activated carbon were used as adsorbents for the successful removal of Reactive Red M-2BE textile dye from aqueous solutions. The adsorbents were characterised by infrared spectroscopy, N(2) adsorption/desorption isotherms and scanning electron microscopy. The effects of pH, shaking time and temperature on adsorption capacity were studied. In the acidic pH region (pH 2.0), the adsorption of the dye was favourable using both adsorbents. The contact time to obtain equilibrium at 298 K was fixed at 1 h for both adsorbents. The activation energy of the adsorption process was evaluated from 298 to 323 K for both adsorbents. The Avrami fractional-order kinetic model provided the best fit to the experimental data compared with pseudo-first-order or pseudo-second-order kinetic adsorption models. For Reactive Red M-2BE dye, the equilibrium data were best fitted to the Liu isotherm model. Simulated dyehouse effluents were used to check the applicability of the proposed adsorbents for effluent treatment. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Aqueous-Solutions, Azo-Dye, Biosorbent, Biosorption, Dye, Electron Microscopy, Equilibrium, Isotherm, Isotherms, Kinetic, Kinetic Model, Kinetics, Methylene-Blue, Multi-Walled Carbon Nanotube, Multi-Walled Carbon Nanotubes, Multiwalled Carbon Nanotubes, Nonlinear Isotherm Fitting, pH, Pine-Fruit Shell, Powdered Activated Carbon, Pseudo Second Order, Reactive Red M-2BE Dye, Removal, Temperature, Thermodynamics, Water

? Yu, F., Ma, J. and Wu, Y.Q. (2011), Adsorption of toluene, ethylbenzene and m-xylene on multi-walled carbon nanotubes with different oxygen contents from aqueous solutions. Journal of Hazardous Materials, 192 (3), 1370-1379.

Full Text: 2011\J Haz Mat192, 1370.pdf

Abstract: The purified and oxidized multi-walled carbon nanotubes (MWCNTs) with different oxygen contents are employed as adsorbents to study their physicochemical properties and adsorption behaviors of toluene, ethylbenzene and m-xylene (TEX) in aqueous solutions. The results demonstrate that adsorption capacity is significantly enhanced for 3.2% surface oxygen, but is dramatically reduced for 5.9% oxygen concentration. The adsorption kinetics is investigated and fitted with pseudo-second-order model. The adsorption isotherms are found to be fitted with Langmuir model. More interestingly, with the increasing of surface oxygen content, maximum adsorption capacities firstly increased, and then, began to decrease. In the first stage, dispersion is the most important factor. A better dispersive interaction increases the available adsorption sites, which consequently can be favorable for the aqueous phase adsorption. Therefore, maximum adsorption capacity is remarkably enhanced with the increasing of oxygen content, which is according with our results. However, in the second stage, when oxygen content increases to a certain extent, hydroxyl groups cause water clusters formation on the surface or tube end of MWCNTs, which hinder the interaction between TEX and MWCNTs. Consequently, more oxygen content leads to the decrease in maximum adsorption capacity. The decrease indicates that the formation of water clusters plays a more important role than the better dispersion of MWCNTs for TEX adsorption. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Acid, Activated Carbons, Adsorption, Adsorption Isotherms, Adsorption Kinetics, Aromatic-Compounds, Chemistry, Isotherms, Kinetics, Langmuir, Mechanisms, Multi-Walled Carbon Nanotube, Multiwalled Carbon Nanotubes, Organic-Chemicals, Pseudo Second Order, Sorption, Surface Oxides, Surface Oxygen Content, Tex, Thermodynamics, Water

? Dai, Y.R., Niu, J.F., Yin, L.F., Xu, J.J. and Xi, Y.H. (2011), Sorption of polycyclic aromatic hydrocarbons on electrospun nanofibrous membranes: Sorption kinetics and mechanism. Journal of Hazardous Materials, 192 (3), 1409-1417.

Full Text: 2011\J Haz Mat192, 1409.pdf

Abstract: Five types of nanofibrous membranes were prepared by electrospinning poly(e-caprolactone) (PCL), poly(D,L-lactide) (PDLLA), poly(lactide-co-caprolactone) (P(LA/CL)), poly(D,L-lactide-co-glycolide) (PDLGA) and methoxy polyethylene glycol-poly(lactide-co-glycolide) (MPEG-PLGA), respectively. These electrospun nanofibrous membranes (ENFMs) were used to adsorb anthracene (ANT), benz[a]anthracene (BaA) and benzo[a]pyrene (BaP) from aqueous solution, and the sorption kinetics and isotherms of these PAHs on the five ENFMs were investigated. The pseudo-second-order model (PSOM) can well describe the sorption kinetics of the three PAHs on five ENFMs, and the partition-adsorption model (PAM) can interpret the sorption processes of PAHs on the ENFMs. PCL ENFMs, which had the largest surface areas (8.57 m² g^-1), exhibited excellent sorption capacity for ANT at over 4112.3±35.5 mu g g^-1. Moreover, the hydrophobicity and pore volume of ENFMs significantly affected the sorption kinetics and sorption capacity of the PAHs. The main sorption mechanisms of three PAHs on the PDLLA ENFMs included hydrophobic interactions and pore-filling, while those of PCL, P(LA/CL) and PDLGA ENFMs were dominated by the hydrophobic interactions. The sorption mechanisms of MPEG-PLGA ENFMs primarily included pore-filling, hydrogen bonding interactions and hydrophobic interactions. Additionally. pi-pi bonding interaction was also deduced to be involved in all of ENFMs sorption systems. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: 17-α-Ethinyl Estradiol, Adsorption-Kinetics, And Isotherms, Aqueous Solution, Bisphenol-A, Electrospun Nanofibrous Membranes, Irradiation, Isotherms, Kinetics, Mechanism, Naphthalene, PAHs, PAHs, Photolysis, Polymer Nanofibers, Pseudo Second Order, Sorption, Sorption Isotherm, Sorption Kinetics, Sorption Mechanisms, Water, Water Treatment, Yellow-River

? Ai, L.H., Zhang, C.Y. and Chen, Z.L. (2011), Removal of methylene blue from aqueous solution by a solvothermal-synthesized graphene/magnetite composite. Journal of Hazardous Materials, 192 (3), 1515-1524.

Full Text: 2011\J Haz Mat192, 1515.pdf

Abstract: In this study, we have demonstrated a facile one-step solvothermal method for the synthesis of the graphene nanosheet (GNS)/magnetite (Fe(3)O(4)) composite. During the solvothermal treatment, in situ conversion of FeCl(3) to Fe(3)O(4) and simultaneous reduction of graphene oxide (GO) into graphene in ethylene glycol solution were achieved. Electron microscopy study suggests the Fe(3)O(4) spheres with a size of about 200 nm are uniformly distributed and firmly anchored on the wrinkled graphene layers with a high density. The resulting GNS/Fe(3)O(4) composite shows extraordinary adsorption capacity and fast adsorption rates for removal of organic dye, methylene blue (MB), in water. The adsorption kinetics, isotherms and thermodynamics were investigated in detail to reveal that the kinetics and equilibrium adsorptions are well-described by pseudo-second-order kinetic and Langmuir isotherm model, respectively. The thermodynamic parameters reveal that the adsorption process is spontaneous and endothermic in nature. This study shows that the as-prepared GNS/Fe(3)O(4) composite could be utilized as an efficient, magnetically separable adsorbent for the environmental cleanup. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorbent, Adsorption, Adsorption Kinetics, Aqueous Solution, Bottom Ash, Carbon Nanotubes, Composite, Dye, Equilibrium, Graphene, Graphene Oxide, Graphite Oxide, Hazardous Dye, Industry Waste, Isotherm, Isotherms, Kinetic, Kinetics, Langmuir, Langmuir Isotherm, Low-Cost Adsorbents, Magnetic Composites, Magnetite, Methylene Blue, Pseudo Second Order, Removal, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Waste Materials, Water

? Asenjo, N.G., Álvarez, P., Granda, M., Blanco, C., Santamaría, R. and Menéndez, R. (2011), High performance activated carbon for benzene/toluene adsorption from industrial wastewater. Journal of Hazardous Materials, 192 (3), 1525-1532.

Full Text: 2011\J Haz Mat192, 1525.pdf

Abstract: A coal-tar-derived mesophase was chemically activated to produce a high surface area (similar to 3200 m(2)/g) carbon with a porosity made up of both micropores and mesopores. Its adsorption capacities were found to be among the highest ever reported in literature, reaching values of 860 mg/g and 1200 mg/g for the adsorption of benzene and toluene, respectively, and 1200 mg/g for the combined adsorption of benzene and toluene from an industrial wastewater. Such high values imply that the entire pore system, including the mesopore fraction, is involved in the adsorption process. The almost complete pore filling is thought to be due to the high relative concentrations of the tested solutions, resulting from the low saturation concentration values for benzene and toluene, which were obtained by fitting the adsorption data to the BET equation in liquid phase. The kinetics of adsorption in the batch experiments which were conducted in a syringe-like adsorption chamber was observed to proceed in accordance with the pseudo-second order kinetic model. The combined presence of micropores and mesopores in the material is thought to be the key to the high kinetic performance, which was outstanding in a comparison with other porous materials reported in the literature. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Anthracene Oil, Behavior, Benzene, Benzene, Industrial Wastewater, Isotherm, Kinetic, Kinetic Model, Kinetics, Kinetics, Mesophase, Mixture, Model, Pseudo Second Order, Sorption, Toluene, Toluene Adsorption, Wastewater

? Goel, N.K., Kumar, V., Pahan, S., Bhardwaj, Y.K. and Sabharwal, S. (2011), Development of adsorbent from Teflon waste by radiation induced grafting: Equilibrium and kinetic adsorption of dyes. Journal of Hazardous Materials, 193, 17-26.

Full Text: 2011\J Haz Mat193, 17.pdf

Abstract: Mutual radiation grafting technique was employed to graft polyacrylic acid (PAA) onto Polytetrafluoroethylene (Teflon) scrap using high energy gamma radiation. Polyacrylic acid-g-Teflon (PAA-g-Teflon) adsorbent was characterized by grafting extent measurement, FTIR spectroscopy, SEM and wet ability & surface energy analysis. The PAA-g-Teflon adsorbent was studied for dye adsorption from aqueous solution of basic dyes, namely. Basic red 29 (BR29) and Basic yellow 11 (BY11). The equilibrium adsorption data were analyzed by Langmuir and Freundlich adsorption isotherm models, whereas, adsorption kinetics was analyzed using pseudo-first order, pseudo-second order and intra-particle diffusion kinetic models. Equilibrium adsorption of BR29 was better explained by Langmuir adsorption model, while that of BY11 by Freundlich adsorption model. The adsorption capacity for BY11 was more than for BR29. Separation factor (R_L) was found to be in the range 0 < R_L < 1, indicating favorable adsorption of dyes. Higher coefficient of determination (r² > 0.99) and better agreement between the q_(e,cal) and q_(e,exp) values suggested that pseudo-second order kinetic model better represents the kinetic adsorption data. The non-linearity obtained for intra-particle diffusion plot indicated, more than one process is involved in the adsorption of basic dyes. The desorption studies showed that similar to 95% of the adsorbed dye could be eluted in suitable eluent. (C) 2011 Published by Elsevier B.V.

Keywords: Acid, Acrylic Acid, Adsorption, Aqueous-Solution, Basic Dyes, Chitosan, Chloride, Cotton, Equilibrium, FTIR, Grafting, Isotherm, Kinetics, Langmuir, Membranes, Radiation, Reactive Dyes, Removal, Separation, Sorption, Teflon Scrap, Thermodynamics

? Caliskan, N., Kul, A.R., Alkan, S., Sogut, E.G. and Alacabey, İ. (2011), Adsorption of Zinc(II) on diatomite and manganese-oxide-modified diatomite: A kinetic and equilibrium study. Journal of Hazardous Materials, 193, 27-36.

Full Text: 2011\J Haz Mat193, 27.pdf

Abstract: The removal of Zn(II) ions from aqueous solution was studied using natural and MnO₂ modified diatomite samples at different temperatures. The linear Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption equations were applied to describe the equilibrium isotherms. From the D-R model, the mean adsorption energy was calculated as >8 kJ mol^-1, indicating that the adsorption of Zn(II) onto diatomite and Mn-diatomite was physically carried out. In addition, the pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to determine the kinetic data. The experimental data were well fitted by the pseudo-second-order kinetic model. Thermodynamic parameters such as the enthalpy (ΔH₀), Gibbs’ free energy (ΔG₀) and entropy (ΔS₀) were calculated for natural and MnO₂ modified diatomite. These values showed that the adsorption of Zn(II) ions onto diatomite samples was controlled by a physical mechanism and occurred spontaneously. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated Kaolinites, Adsorption, Aqueous-Solution, Diatomaceous-Earth, Diatomite, Heavy-Metals, Ions, Kinetic, Langmuir, Manganese Oxides, Methylene-Blue, Natural Diatomite, Removal, Sorption, Surface-Chemistry, Thermodynamic, Thermodynamic Parameters, Zinc

? Lin, J.W., Zhan, Y.H., Zhu, Z.L. and Xing, Y.Q. (2011), Adsorption of tannic acid from aqueous solution onto surfactant-modified zeolite. Journal of Hazardous Materials, 193, 102-111.

Full Text: 2011\J Haz Mat193, 102.pdf

Abstract: Surfactant-modified zeolites (SMZs) with various loadings of cetylpyridinium bromide (CPB) were used as adsorbents to remove tannic acid (TA) from aqueous solution. The TA adsorption efficiencies for natural zeolite and various SMZs were compared. SMZ presented higher TA adsorption efficiency than natural zeolite, and SMZ with higher loading amount of CPB exhibited higher TA adsorption efficiency. The adsorption of TA onto SMZ as a function of contact time, initial adsorbate concentration, temperature, ionic strength, coexisting Cu(II) and solution pH was investigated. The adsorbents before and after adsorption were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FT-IR) spectroscopy. The adsorption kinetics of TA onto SMZ with CPB bilayer coverage (SMZ-CBC) followed a pseudo-second-order model. The equilibrium adsorption data of TA onto SMZ-CBC were well represented by Langmuir, Redlich-Peterson and Sips isotherm models. The calculated thermodynamic parameters indicated that TA adsorption onto SMZ-CBC was spontaneous and exothermic. The TA adsorption capacity for SMZ-CBC slightly decreased with increasing ionic strength but significantly increased with increasing Cu(II) concentration. The TA adsorption capacity for SMZ-CBC was relatively high at solution pH 4.0-7.0, and decreased with an increase in solution pH from 7.0 to 8.5. The mechanisms controlling TA adsorption onto SMZ-CBC at solution pH 5.5 include electrostatic attraction, hydrogen bonding and organic partitioning. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Cationic Surfactant, Cetylpyridinium Bromide, Chromate, Clay, Cu(II), Equilibrium, FTIR, Isotherm, Kinetics, Langmuir, Lead, Mechanisms, Modified Natural Zeolite, pH, Removal, Sorption, Surfactant-Modified Zeolite, Tannic Acid

? Benaïssa, H. and Elouchdi, M.A. (2011), Biosorption of copper (II) ions from synthetic aqueous solutions by drying bed activated sludge. Journal of Hazardous Materials, 194, 69-78.

Full Text: 2011\J Haz Mat194, 69.pdf

Abstract: In the present work, the usefulness of dried activated sludge has been investigated for the removal of copper ions from synthetic aqueous solutions. Kinetic data and equilibrium sorption isotherm were measured in batch conditions. The influence of some parameters such as: contact time, initial copper concentration, initial pH of solution and copper salt nature on copper biosorption kinetics has been studied. Copper uptake was time contact, initial copper concentration, initial pH solution and copper salt type dependent. Maximum copper sorption was found to occur at initial pH 5. Two simplified kinetic models including a first-order rate equation and a pseudo second-order rate equation were selected to describe the biosorption kinetics. The process followed a pseudo second-order rate kinetics. The process mechanism was found to be complex, consisting of external mass transfer and intraparticle mass transfer diffusion. Copper biosorption process was particle-diffusion-controlled, with some predominance of some external mass transfer at the initial stages for the different experimental parameters studied. Langmuir and Freundlich models were used to describe sorption equilibrium data at natural pH of solution. Results indicated that the Langmuir model gave a better fit to the experimental data than the Freundlich model. Maximum copper uptake obtained was q_m = 62.50 mg/g (0.556 mmol/g) under the investigated experimental conditions. Scanning electron microscopy coupled with X-ray energy dispersed analysis for copper-equilibrated dried activated sludge demonstrated that copper existed on its surface. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Biosorption, Cadmium Biosorption, Copper Ions, Dried Activated Sludge, Equilibrium, Equilibrium, Heavy-Metal Removal, Isotherm, Kinetic, Kinetics, Kinetics, Langmuir, Low-Cost, Marine-Algae, pH, Sewage-Sludge, Sorption, Waste-Water

? Ko, Y.G., Chun, Y.J., Kim, C.H. and Choi, U.S. (2011), Removal of Cu(II) and Cr(VI) ions from aqueous solution using chelating fiber packed column: Equilibrium and kinetic studies. Journal of Hazardous Materials, 194, 92-99.

Full Text: 2011\J Haz Mat194, 92.pdf

Abstract: Herein, we demonstrate the adsorption process system with the diethylenetriamne coupled polyacrylonitrile fiber for the removal of Cu(II) and Cr(VI) ions in the aqueous solution. The synthesized chelating fiber showed a high adsorption capacity of 11.4 mequiv/g. Interestingly, the crystal growth of copper ions on the chelating fiber was observed during the adsorption process. The chelating fiber packed column showed the high performance of the removal of Cu(II) in the aqueous solution due to the distinct characteristic of the crystal growth of metal ions on the chelating fiber. After Cu(II) adsorption on the chelating fiber, the color of the fiber changed to light blue from yellow. The isotherm parameter n of 1.991 was obtained with Freundlich isotherm model for the adsorption equilibrium study which indicates that Cu(II) adsorption on the chelating fiber is very favorable due to n > 1. The pseudo-first-order and pseudo-second-order model equations were used for the kinetic study. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption, Amine Group, Chelating Fiber, Cr(VI), Crystal Growth of Metal Ions, Cu(II), Equilibrium, Heavy Metal Ions, Isotherm, Metal-Complexes, Model, Polymers, Removal, Sorption, Spectroscopy

? Song, X.H., Gunawan, P., Jiang, R.R., Leong, S.S.J., Wang, K.A. and Xu, R. (2011), Surface activated carbon nanospheres for fast adsorption of silver ions from aqueous solutions. Journal of Hazardous Materials, 194, 162-168.

Full Text: 2011\J Haz Mat194, 162.pdf

Abstract: We report the synthesis and activation of colloidal carbon nanospheres (CNS) for adsorption of Ag(I) ions from aqueous solutions. CNS (400-500 nm in diameter) was synthesized via simple hydrothermal treatment of glucose solution. The surface of nonporous CNS after being activated by NaOH was enriched with -OH and –COO^- functional groups. Despite the low surface area (<15 m²/g), the activated CNS exhibited a high adsorption capacity of 152 mg silver/g. Under batch conditions, all Ag(I) ions can be completely adsorbed in less than 6 min with the initial Ag(I) concentrations lower than 2 ppm. This can be attributed to the minimum mass transfer resistance as Ag(I) ions were all deposited and reduced as Ag(0) nanoparticles on the external surface of CNS. The kinetic data can be well fitted to the pseudo-second-order kinetics model. The adsorbed silver can be easily recovered by dilute acid solutions and the CNS can be reactivated by the same treatment with NaOH solution. The excellent adsorption performance and reusability have also been demonstrated in a continuous mode. The NaOH activated CNS reported here could represent a new type of low-cost and efficient adsorbent nanomaterials for removal of trace Ag(I) ions for drinking water production. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activation, Adsorption, Carbon Nanosphere, Chitosan Resin, Functional-Groups, Glucose, Heavy-Metal Ions, Hydroxide, Kinetics, Microparticles, Nanocrystals, Nanoparticles, Removal, Silver, Sodium Hydroxide, Spheres, Surface Activation

? Fan, L.L., Luo, C.N., Lv, Z., Lu, F.G. and Qiu, H.M. (2011), Removal of Ag⁺ from water environment using a novel magnetic thiourea-chitosan imprinted Ag⁺. Journal of Hazardous Materials, 194, 193-201.

Full Text: 2011\J Haz Mat194, 193.pdf

Abstract: A novel, thiourea-chitosan coating on the surface of magnetite (Fe₃O₄) (Ag-TCM) was successfully synthesized using Ag(l) as imprinted ions for adsorption and removal of Ag(1) ions from aqueous solutions. The thermal stability, chemical structure and magnetic property of the Ag-TCM were characterized by the scanning electron microscope (SEM), Fourier transform infrared spectrometer (Fr-IR) and vibrating sample magnetometer (VSM), respectively. Batch adsorption experiments were performed to evaluate the adsorption conditions, selectivity and reusability. The results showed that the maximum adsorption capacity was 4.93 mmol/g, observed at pH 5 and temperature 30°C. Equilibrium adsorption was achieved within 50 min. The kinetic data, obtained at the optimum pH 5, could be fitted with a pseudo-second order equation. Adsorption process could be well described by Langmuir adsorption isotherms and the maximum adsorption capacity calculated from Langmuir equation was 5.29 mmol/g. The selectivity coefficient of Ag(I) ions and other metal cations onto Ag-TCM indicated an overall preference for Ag(I) ions, which was much higher than non-imprinted thiourea-chitosan beads. Moreover, the sorbent was stable and easily recovered, the adsorption capacity was about 90% of the initial saturation adsorption capacity after being used five times. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Properties, Ag⁺, Anion-Exchange Resins, Aqueous-Solution, Carboxymethyl-Chitosan, Equilibrium, Langmuir, Magnetite, Methylene-Blue, Nano-Adsorbent, pH, Polymer, Reactive Dyes, Removal, Solid-Phase Extraction, Textile Wastewaters, Thiourea-Chitosan

? Volchek, K., Miah, M.Y., Kuang, W.X., DeMaleki, Z. and Tezel, F.H. (2011), Adsorption of cesium on cement mortar from aqueous solutions. Journal of Hazardous Materials, 194, 331-337.

Full Text: 2011\J Haz Mat194, 331.pdf

Abstract: The adsorption of cesium on cement mortar from aqueous solutions was studied in series of bench-scale tests. The effects of cesium concentration, temperature and contact time on process kinetics and equilibrium were evaluated. Experiments were carried out in a range of initial cesium concentrations from 0.0103 to 10.88 mg L^-1 and temperatures from 278 to 313 K using coupons of cement mortar immersed in the solutions. Non-radioactive cesium chloride was used as a surrogate of the radioactive (137)Cs. Solution samples were taken after set periods of time and analyzed by inductively coupled plasma mass spectroscopy. Depending on the initial cesium concentration, its equilibrium concentration in solution ranged from 0.0069 to 8.837 mg L^-1 while the respective surface concentration on coupons varied from 0.0395 to 22.34 mu g cm^-2. Equilibrium test results correlated well with the Freundlich isotherm model for the entire test duration. Test results revealed that an increase in temperature resulted in an increase in adsorption rate and a decrease in equilibrium cesium surface concentration. Among several kinetic models considered, the pseudo-second order reaction model was found to be the best to describe the kinetic test results in the studied range of concentrations. The adsorption activation energy determined from Arrhenius equation was found to be approximately 55.9 kJ mol^-1 suggesting that chemisorption was the prevalent mechanism of interaction between cesium ions and cement mortar. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.

Keywords: Activation, Adsorption, Cement Mortar, Cesium, Chernobyl, Concrete, Copper, Different Physicochemical Conditions, Diffusion, Equilibrium, Equilibrium, Granite, Ions, Isotherm, Kinetic, Kinetics, Montmorillonite, Removal, Surfaces

? Lu, X., Yin, Q.F., Xin, Z., Li, Y. and Han, T. (2011), Synthesis of poly(aminopropyl/methyl)silsesquioxane particles as effective Cu(II) and Pb(II) adsorbents. Journal of Hazardous Materials, 196, 234-241.

Full Text: 2011\J Haz Mat196, 234.pdf

Abstract: Poly(aminopropyl/methyl)silsesquioxane (PAMSQ) particles have been synthesized by a one-step hydrolytic co-condensation process using 3-aminopropyltriethoxysilane (APTES) and methyltrimethoxysilane (MTMS) as precursors in the presence of base catalyst in aqueous medium. The amino functionalities of the particles could be controlled by adjusting the organosilanes feed ratio. The compositions of the amino-functionalized polysilsesquioxanes were confirmed by FT-IR spectroscopy, solid-state (29)Si NMR spectroscopy, and elemental analysis. The strong adsorbability of Cu(II) and Pb(II) ions onto PAMSQ particles was systematically examined. The effect of adsorption time, initial metal ions concentration and pH of solutions was studied to optimize the metal ions adsorbability of PAMSQ particles. The kinetic studies indicated that the adsorption process well fits the pseudo-second-order kinetics. Adsorption phenomena appeared to follow Langmuir isotherm. The PAMSQ particles demonstrate the highest Cu(II) and Pb(II) adsorption capacity of 2.29 mmol/g and 1.31 mmol/g at an initial metal ions concentration of 20 mM, respectively. The PAMSQ particles demonstrate a promising application in the removal of Cu(II) and Pb(II) ions from aqueous solutions. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: 3-Aminopropyltriethoxysilane, Acid, Activated Carbon, Adsorption, Adsorption, Aqueous-Solution, Copper, Copper(II), Cu(II), FTIR, Heavy-Metal Removal, Immobilized Ligand System, Ions, Isotherm, Kinetic, Kinetics, Langmuir, Lead, Microparticles, Nanoparticles, Particle, pH, Poly(aminopropyl, methyl)silsesquioxane

? Addorisio, V., Pirozzi, D., Esposito, S. and Sannino, F. (2011), Decontamination of waters polluted with simazine by sorption on mesoporous metal oxides. Journal of Hazardous Materials, 196, 242-247.

Full Text: 2011\J Haz Mat196, 242.pdf

Abstract: Two mesoporous metal oxides, Al₂O₃ and Fe₂O₃, were evaluated as regards their ability to remove simazine, a highly persistent herbicide of s-triazines, using a batch equilibrium method. The effect of several experimental parameters such as pH, contact time, initial concentration and sorbent dosage on the sorption of the herbicide was investigated. The maximum sorption of simazine on Al₂O₃ and Fe₂O₃ was observed at pH 6.5 and 3.5, respectively. The different sorption capacities of the two oxides were explained considering a set of factors affecting the sorption process such as the surface area and the porosity. The kinetics of sorption on both oxides was described using a pseudo second-order model. The sorption of simazine on Fe₂O₃ was faster in comparison to that observed on Al₂O₃. It was shown that aluminum oxide can be regenerated by incineration, and consequently can be considered for industrial treatment systems designed to mitigate the pesticide pollution in the aquatic environments. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorbents, Adsorption, Aluminum, Atrazine, Binding, Decontamination, Kinetics, Mesoporous Metal Oxides, Pesticides, pH, Regeneration, Removal, Separation, Simazine, Soil, Sorption, Triazine

? Mahmoodi, N.M., Najafi, F., Khorramfar, S., Amini, F. and Arami, M. (2011), Synthesis, characterization and dye removal ability of high capacity polymeric adsorbent: Polyaminoimide homopolymer. Journal of Hazardous Materials, 198, 87-94.

Full Text: 2011\J Haz Mat198, 87.pdf

Abstract: In this paper, polyaminoimide homopolynner (PAIHP) was synthesized and its dye removal ability was investigated. Physical characteristics of PAIHP were studied using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). Direct Red 31 (DR31), Direct Red 23 (DR23), Direct Black 22 (DB22) and Acid Blue 25 (AB25) were used as model compounds. The kinetic and isotherm of dye adsorption were studied. The effect of operational parameter such as adsorbent dosage, pH and salt on dye removal was evaluated. Adsorption kinetic of dyes followed pseudo-second order kinetics. The maximum dye adsorption capacity (Q(0)) of PAIHP was 6667 mg/g, 5555 mg/g, 9090 mg/g and 5882 mg/g for DR31, DR23, DB22 and AB25, respectively. It was found that adsorption of DR31, DR23, DB22 and AB25 onto PAIHP followed with Langmuir isotherm. Dye desorption tests (adsorbent regeneration) showed that the maximum dye release of 90% for DR31, 86% for DR23, 87% for DB22 and 90% for AB25 were achieved in aqueous solution at pH 12. The results showed that the PAIHP as a polymeric adsorbent with high dye adsorption capacity might be a suitable alternative to remove dyes from colored wastewater. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorbent, Adsorbent Regeneration, Adsorption, Adsorption Kinetic, Aqueous-Solutions, Binary-Systems, Chitosan, Desorption, Dye Adsorption, Dye Removal, Equilibrium, FTIR, Fundamental Properties, Isotherm, Kinetic, Kinetics, Langmuir, Langmuir Isotherm, pH, Polyaminoimide Homopolymer, Regeneration, Synthesis, Textile Waste-Water, Thermodynamics, Wastewater

? Ai, L.H., Zhang, C.Y., Liao, F., Wang, Y., Li, M., Meng, L.Y. and Jiang, J. (2011), Removal of methylene blue from aqueous solution with magnetite loaded multi-wall carbon nanotube: Kinetic, isotherm and mechanism analysis. Journal of Hazardous Materials, 198, 282-290.

Full Text: 2011\J Haz Mat198, 282.pdf

Abstract: In this study, we have demonstrated the efficient removal of cationic dye, methylene blue (MB), from aqueous solution with the one-pot solvothermal synthesized magnetite-loaded multi-walled carbon nanotubes (M-MWCNTs). The as-prepared M-MWCNTs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The effects of contact time, initial dye concentration, and solution pH on the adsorption of MB onto M-MWCNTs were systematically studied. It was shown that the MB adsorption was pH-dependent. Adsorption kinetics was best described by the pseudo-second-order model. Equilibrium data were well fitted to the Langmuir isotherm model, yielding maximum monolayer adsorption capacity of 48.06 mg g^-1 FTIR analysis suggested that the adsorption mechanism was possibly attributed to the electrostatic attraction and it-it stacking interactions between MWCNTs and MB. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorbent, Adsorption, Adsorption, Adsorption Kinetics, Composite, Concentration, Dye Solution, Equilibrium, FTIR, Heavy-Metals, Isotherm, Kinetic, Kinetics, Langmuir, Langmuir Isotherm, Magnetite, Mechanism, Methylene Blue, Multi-Walled Carbon Nanotubes, Nanoparticles, pH, Removal, Separation Performance, Waste, Water, X-Ray Diffraction

? Jin, X.L., Li, Y.F., Yu, C., Ma, Y.X., Yang, L.Q. and Hu, H.Y. (2011), Synthesis of novel inorganic-organic hybrid materials for simultaneous adsorption of metal ions and organic molecules in aqueous solution. Journal of Hazardous Materials, 198, 247-256.

Full Text: 2011\J Haz Mat198, 247.pdf

Abstract: In this paper, atom transfer radical polymerization (ATRP) and radical grafting polymerization were combined to synthesize a novel amphiphilic hybrid material, meanwhile, the amphiphilic hybrid material was employed in the absorption of heavy metal and organic pollutants. After the formation of attapulgite (ATP) ATRP initiator, ATRP block copolymers of styrene (St) and divinylbenzene (DVB) were grafted from it as ATP-P(S-b-DVB). Then radical polymerization of acrylonitrile (AN) was carried out with pendent double bonds in the DVD units successfully, finally we got the inorganic-organic hybrid materials ATPP(S-b-DVB-g-AN). A novel amphiphilic hybrid material ATP-P(S-b-DVB-g-AO) (ASDO) was obtained after transforming acrylonitrile (AN) units into acrylamide oxime (AO) as hydrophilic segment. The adsorption capacity of ASDO for Pb(II) could achieve 131.6 mg/g, and the maximum removal capacity of ASDO towards phenol was found to be 18.18 mg/g in the case of monolayer adsorption at 30 C. The optimum pH was 5 for both lead and phenol adsorption. The adsorption kinetic suited pseudo-second-order equation and the equilibrium fitted the Freundlich model very well under optimal conditions. At the same time FT-IR. TEM and TGA were also used to study its structure and property. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorbent, Adsorption, Amphiphilic, Block-Copolymer Brushes, Equilibrium, Freundlich, FT-IR, FTIR, Fungal Biomass, Heavy Metal, Hybrid Materials, Kinetic, Lead Adsorption, Metal Ions, Pb(II), pH, Phenol, Phenolic-Compounds, Ps-EDTA Resin, Removal, Synthesis, Transfer Radical Polymerization, Waste-Water

? Ho, Y.S. (2011), Comment on “comparison of two-stage sorption design models for the removal of lead ions by polyvinyl-modified Kaolinite clay”. Journal of Hazardous Materials, 198 (1), 387.

Full Text: 2011\J Haz Mat198, 387.pdf; 2011\J Haz Mat-Ho1.pdf; 2011\J Haz Mat-Ho.pdf