Personal Research Database

187 (1-3), 562-573.

Full Text: 2011\J Haz Mat187, 562.pdf

Abstract: This investigation reveals the adsorption characteristics of two basic dyes, thionine (TH) and safranine T (ST), onto fly ash (FA) and its three zeolitized products prepared at different hydrothermal conditions. Typical two-step isotherms were observed for TH adsorption onto four adsorbents, whereas the isotherms of the larger ST molecules were S-shaped. The adsorption capacities of the zeolitized fly ash (ZFA) estimated from the first plateau region of the TH isotherms was nearly twice the FA capacity. The capacities increased by up to five times in the second plateau region. The adsorption capacity of FA for ST is equivalent that of TH, whereas the capacities of ZFA are lower than those found for TH. The equilibrium results were well-described by the Freundlich isotherm model. The kinetic data obtained in the temperature range of 298-318 K was analyzed using Paterson’s and Nernst Plank’s approximations based on the homogeneous surface diffusion model (HSDM). The thermodynamic functions for the transition state were evaluated from the temperature-dependence of the surface diffusion coefficients by applying the Eyring model. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorbents, Adsorption, Adsorption Capacities, Adsorption Capacity, Aqueous-Solution, Basic Dye, Basic Dyes, Capacity, Characteristics, Coal Ash, Comparison, Data, Diffusion, Diffusion Coefficients, Diffusion Model, Dye, Dye Adsorption, Dye-Adsorption, Dyes, Equilibrium, First, Fly Ash, Fly Ash Zeolites, Freundlich, Freundlich Isotherm, Freundlich Isotherm Model, Functions, Hsdm, Investigation, Isotherm, Isotherm Model, Isotherms, Kinetic, Kinetic Data, Kinetics, Mar, Methylene-Blue, Model, Na-X, Natural Zeolite, Region, Removal, Rights, Safranine T, State, Surface, Surface Diffusion, Temperature, Thermodynamic, Thermodynamic Functions, Thionine, Toluidine-Blue, Waste-Water

? Elwakeel, K.Z. and Rekaby, M. (2011), Efficient removal of Reactive Black 5 from aqueous media using glycidyl methacrylate resin modified with tetraethelenepentamine. Journal of Hazardous Materials, 188 (1-3), 10-18.

Full Text: 2011\J Haz Mat188, 10.pdf

Abstract: Glycidyl methacrylate/methelenebisacrylimide resin loaded with tetraethelenepentamine ligand was prepared and investigated. The adsorption characteristics of the obtained resin towards Reactive Black 5 (RB5) from aqueous solutions at different experimental conditions were established by means of batch and column methods. The mechanism of interaction between RB5 and resin’s active sites was discussed. The resin showed high affinity for the adsorption of RB5 where an uptake value of 0.63 mmol/g was reported for the obtained resin, at 25ºC. The kinetics and thermodynamic behavior of the adsorption reaction were also defined. These data indicated an endothermic spontaneous adsorption process and kinetically followed the pseudo-second order model. Breakthrough curves for the removal of RB5 were studied at different flow rates and bed heights. The critical bed height for the studied resin column was found to be 0.764cm at flow rate of 8 mL/min. The adsorbed dye was eluted from the investigated resin effectively. Regeneration and durability of the loaded resin towards the successive resin were also clarified. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Behavior, Chitosan, Color, Dye, Dyes, Effluents, Glycidyl Methacrylate, Kinetics, Mechanism, Metal-Ions, Microbial Decolorization, RB5, Reactive Black 5, Regeneration, Resin, Thermodynamic, Thermodynamics, Waste-Water

? Priyantha, N. and Bandaranayaka, A. (2011), Investigation of kinetics of Cr(VI)-fired brick clay interaction. Journal of Hazardous Materials, 188 (1-3), 193-197.

Full Text: 2011\J Haz Mat188, 193.pdf

Abstract: Fired brick clay is an excellent sorbent for the removal of heavy metal ions from waste water, owing to the availability of pores and interlayer spacing. Consequently, heat treatment of brick clay significantly affects the extent of interaction between the brick clay sorbent and adsorbates. The interaction between Cr(VI), available as Cr₂O₇^2-, and brick clay particles fired at temperatures between 200ºC and 600ºC follows pseudo second order kinetics, and the method of initial rates leads to the estimation of the average rate of the interaction process. Kinetics modeling suggests that the mass transfer of the interaction be mainly controlled by time-dependent intraparticle diffusion, as well as immobilization of Cr(VI) species within interlayer structure of the brick clay matrix and interparticle diffusion, both of which are time-independent. (C) 2011 Published by Elsevier B.V.

Keywords: Adsorption, Aqueous-Solution, Biosorption, Brick Clay, Carbon, Chromium, Cr(Vi), Hexavalent Chromium, Immobilization, Intraparticle Diffusion, Ion, Kinetics, Maize Cob, Modeling, Removal, Sorption, Waste, Water

? Jho, E.H., Lee, S.B., Kim, Y.J. and Nam, K. (2011), Facilitated desorption and stabilization of sediment-bound Pb and Cd in the presence of birnessite and apatite. Journal of Hazardous Materials, 188 (1-3), 206-211.

Full Text: 2011\J Haz Mat188, 206.pdf

Abstract: Desorption of lead (Pb) and cadmium (Cd) from contaminated sediments was investigated to clarify the effect of stabilizing agents on Cd and Pb desorption kinetics. The desorbed aqueous Cd and Pb concentrations and the residual amounts of Cd on the sediments in the desorption tests were best fitted to a pseudo-second-order kinetics with the highest R-2 values among the models used in the kinetic studies. The average residual Cd on sediments were 24% and 19% less in the presence of apatite and birnessite, respectively, than in the absence of them. However, the Pb desorption was not affected by the stabilizing agents. The negligible aqueous concentrations of desorbed Cd and Pb in the presence of apatite and birnessite suggest the stabilization of desorbed Cd that was facilitated by apatite and birnessite and Pb. The kinetics study with Cd shows that the rate constants are not affected, but the desorption extents are affected in the presence of apatite and birnessite. The Tessier sequential extraction method and toxicity characteristic leaching procedure indicate that Pb is more strongly bound on the stabilizing agents than Cd. Overall, birnessite and apatite can be successfully applied in remediation of Cd and Pb contaminated sediment. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Apatite, Birnessite, Cadmium, Desorption, Facilitated Desorption, Heavy Metals, Hydroxyapatite, Kinetic, Kinetics, Metals, Pb, Release, Remediation, Sediment, Sequential Extraction, Soils, Sorption, Technologies, Toxicity

? Cheng, R.C., Xiang, B., Li, Y.J. and Zhang, M.Z. (2011), Application of dithiocarbamate-modified starch for dyes removal from aqueous solutions. Journal of Hazardous Materials, 188 (1-3), 254-260.

Full Text: 2011\J Haz Mat188, 254.pdf

Abstract: The present study shows that the dithiocarbamate-modified starch (DTCS) is a commercially promising sorbent for the removal of anionic dyes from aqueous solutions. It is more effective than activated carbon for this purpose. At the appropriate solution pH of 4, kinetic studies indicate that the sorption of the dyes tends to follow pseudo-first-order equation. The sorption equilibrium is best described by the Langmuir-Freundlich isotherm model at 298K. The capacities for individual dyes follow the sequence acid orange 7 > acid orange 10 > acid red 18 > acid black 1 > acid green 25, which is consistent with the inverse order of molecular size. The negative enthalpy change for the adsorption process confirms the exothermic nature of adsorption, and a free energy change confirms the spontaneity of the process. The FT-IR spectra and thermogravimetric analyses verify the sorption based on starch-NH(2)(+)CSSH center dot center dot center dot(-)O(3)S-dye electrostatic attraction. The DTCS can be regenerated from the dye loaded DTCS in a weak basic solution containing sodium sulfate. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Acid Dyes, Activated Carbon, Adsorbents, Adsorption, Adsorption, Anionic Dye, Chitosan, Dithiocarbamate, Effluent, Energy, Equilibrium, Ftir, Isotherm, Kinetic, Langmuir-Freundlich Isotherm, Mechanism, Mechanism, Model, Modified Starch, Molecular, pH, Pollutants, Polysaccharides, Pseudo-First-Order, Removal, Sorbent, Sorption, Thermodynamics

? Mohan, D., Rajput, S., Singh, V.K., Steele, P.H. and Pittman, C.U. (2011), Modeling and evaluation of chromium remediation from water using low cost bio-char, a green adsorbent. Journal of Hazardous Materials, 188 (1-3), 319-333.

Full Text: 2011\J Haz Mat188, 319.pdf

Abstract: Oak wood and oak bark chars were obtained from fast pyrolysis in an auger reactor at 400-450ºC. These chars were characterized and utilized for Cr(VI) remediation from water. Batch sorption studies were performed at different temperatures, pH values and solid to liquid ratios. Maximum chromium was removed at pH 2.0. A kinetic study yielded an optimum equilibrium time of 48 h with an adsorbent dose of 10 g/L. Sorption studies were conducted over a concentration range of 1-100 mg/L. Cr(VI) removal increased with an increase in temperature (Q º(Oakwood):25ºC = 3.03 mg/g; 35ºC = 4.08 mg/g; 45ºC = 4.93 mg/g and Q º(Oak bark) : 25ºC = 4.62 mg/g; 35ºC = 7.43 mg/g; 45ºC = 7.51 mg/g). More chromium was removed with oak bark than oak wood. The char performances were evaluated using the Freundlich, Langmuir, Redlich-Peterson, Toth. Radke and Sips adsorption isotherm models. The Sips adsorption isotherm model best fits the experimental data [high regression (R-2) coefficients]. The overall kinetic data was satisfactorily explained by a pseudo second order rate expression. Water penetrated into the char walls exposing Cr(VI) to additional adsorption sites that were not on the surfaces of dry char pores. It is remarkable that oak chars (S-BET: 1-3 m² g^-1) can remove similar amounts of Cr(VI) as activated carbon (S-BET: similar to 1000 m² g^-1) Thus, byproduct chars from bio-oil production might be used as inexpensive adsorbents for water purification. Char samples were successfully used for chromium remediation from contaminated surface water with dissolved interfering ions. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Activated Carbons, Adsorption, Adsorption Isotherm, Adsorption-Isotherm, Agricultural Waste Materials, Aqueous-Solution, Batch, Bio-Char, Biomass, Carbon Fabric Cloth, Chitosan, Chromium, Chromium Adsorption, Chromium Removal, Cr(VI), Cr(VI) Removal, Equilibrium, Freundlich, Hexavalent Chromium, Hexavalent Chromium, Isotherm, Kinetic, Langmuir, Lead, Low Cost Adsorbent, pH, Sorption, Toth

? Baidas, S., Gao, B.Y. and Meng, X.G. (2011), Perchlorate removal by quaternary amine modified reed. Journal of Hazardous Materials, 189 (1-2), 54-61.

Full Text: 2011\J Haz Mat189, 54.pdf

Abstract: We report a kinetic and equilibrium study of perchlorate adsorption onto giant reed modified by quaternary amine (QA) functional groups in batch reactors. The effect of pH, contact time, and initial perchlorate concentration on removal was investigated. The adsorption capacity for perchlorate was 169 mg/g on the modified reed (MR) particles ranging in size from 100 to 250 p,m. The isotherm results were best described by the combined Langmuir-Freundlich equation. Optimum removal occurred in the pH range 3.5-7.0 and was reduced at pH > 8.5. The maximum adsorption rate occurred within the first minute of contact and equilibrium was achieved within 7 min. A three-stage adsorption occurred. In stage 1, adsorption was rapid and was controlled by boundary layer diffusion. In stage 2, adsorption was gradual and was controlled by both boundary layer and intraparticle diffusion. In stage 3, adsorption reached a plateau. The kinetic results fit well with a pseudo second-order equation. The adsorption mechanism was explored using Zeta potential analysis and Raman spectroscopy. Zeta potential measurements showed that reed modification enhanced perchlorate removal by increasing the surface potential. Electrostatic attraction between perchlorate anion and positively charged quaternary amine groups on the MR was the primary mechanism responsible for perchlorate removal. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Adsorption, Anion-Exchangers, Aqueous-Solution, Environmental Perchlorate, Equilibrium, Giant Reed, Ion-Exchange Reactions, Isotherm, Kinetic, Mechanism, Modified Reed, Perchlorate, pH, Phosphate Removal, Raman, Raman-Spectroscopy, Sodium-Perchlorate, Zeta Potential

? Rakhshaee, R. and Panahandeh, M. (2011), Stabilization of a magnetic nano-adsorbent by extracted pectin to remove methylene blue from aqueous solution: A comparative studying between two kinds of cross-likened pectin. Journal of Hazardous Materials, 189 (1-2), 158-166.

Full Text: 2011\J Haz Mat189, 158.pdf

Abstract: The removal of methylene blue (MB) as a cationic dye from aqueous solution by the stabilized Fe(3)O(4) nano-particles with the extracted pectin from apple waste (FN-PA) increased due to using the crosslinked forms of the bound pectin on the nano-particles surface by glutaraldehyde (FN-PAG) and adipic acid (FN-PAA) as the cross-linking agents. This increase happened in spite of binding some of the adsorbent functional groups of pectin with nano-particles. It can be due to the local concentrate of other free functional groups after connecting with nano-scale particles. Thermodynamic studies showed that the adsorption equilibrium constant and the maximum adsorption capacities increased with increasing temperature for all of the nano-bioparticles. The kinetic followed the second-order models with the highest rate constants viz. 16.23, 19.76 and 23.04 ( x 10(-3) g/mg min) by FN-PAA. The adsorption force arrangement of MB by these nano-biosorbents regarding their activation energy was obtained as: FN-PAA > FN-PAG > FN-PA. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Activation, Adsorbent, Adsorption, Adsorption Equilibrium, Biosorption, Column, Cross-Linked, Degradation, Energy, Equilibrium, Extracted Pectin, Functional, Granular Activated Carbon, Kinetic, Kinetics, Methylene Blue, Methylene Blue Uptake, Modified Fe₃O₄ Nano-Particles, Reactive Dyes, Removal, Thermodynamic, Water, Zero-Valent Iron

? Li, N.A., Zhang, L.D., Chen, Y.Z., Tian, Y. and Wang, H.M. (2011), Adsorption behavior of Cu(II) onto titanate nanofibers prepared by alkali treatment. Journal of Hazardous Materials, 189 (1-2), 265-272.

Full Text: 2011\J Haz Mat189, 265.pdf

Abstract: Novel low-cost adsorbents of titanate nanofibers with formula NaxH2-xTi₃O₇ center dot nH₂O have been prepared by alkali treatment for Cu(II) removal from aqueous solutions. The nanofibers have structures in which three edge-shared TiO₆ octahedras join at the corners to form stepped, zigzag Ti₃O₇^2- layers. The sodium cations located between the layers are exchangeable. The results of batch adsorption experiments suggest that the nanofibers with high sodium content can be effective adsorbents for Cu(II) removal. Effects of several important factors such as Na amount in adsorbents, pH, temperature, contact time and initial concentration are systematically studied. Results show that the adsorption is highly pH-dependent and the removal is almost complete (99.8%) for initial concentration under 100 mg/l at pH 4. Equilibrium adsorption follows Langmuir isotherms well and the maximum Cu(II) uptake calculated is 167.224 mg/g. The adsorption kinetics can be explained by pseudo-second-order model well and the time needed for equilibrium is 180 min. Thermodynamic study indicates that the adsorption is spontaneous and endothermic. Desorption of Cu(II) from adsorbents using EDTA-2Na solutions exhibits a high efficiency and the adsorbents can be used repeatedly. These results demonstrate that the titanate nanofibers are readily prepared, enabling promising applications for the removal of Cu(II) from aqueous solutions. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Kinetics, Aqueous-Solution, Chemical-Reactions, Chitosan, Cu(II), Cu(II) Adsorption, Desorption, Equilibrium, Hydrothermal Method, Ions, Isotherms, Kinetics, Langmuir, Nanostructured Materials, Pb(II), pH, Removal, Thermodynamic, Titanate Nanofibers, Titanium-Oxide Nanotubes, Waste-Water

? Kilic, M., Apaydin-Varol, E. and Pütün, A.E. (2011), Adsorptive removal of phenol from aqueous solutions on activated carbon prepared from tobacco residues: Equilibrium, kinetics and thermodynamics. Journal of Hazardous Materials, 189 (1-2), 397-403.

Full Text: 2011\J Haz Mat189, 397.pdf

Abstract: This study consists of producing high surface area activated carbon from tobacco residues by chemical activation and its behavior of phenol removal from aqueous solutions. K₂CO₃ and KOH were used as chemical activation agents and three impregnation ratios (50, 75 and 100 wt.%) were applied on biomass. Maximum BET surface areas of activated carbons were obtained from impregnation with 75 wt.% of K₂CO₃ and 75 wt.% of KOH as 1635 and 1474 m²/g, respectively. Optimum adsorption conditions were determined as a function of pH, adsorbent dosage, initial phenol concentration, contact time and temperature of solution for phenol removal. To describe the equilibrium isotherms the experimental data were analyzed by the Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin isotherm models. Pseudo-first order, pseudo-second order and intraparticle diffusion kinetic models were used to find out the kinetic parameters and mechanism of adsorption process. The thermodynamic parameters such as ΔGº, ΔHº and ΔSº were calculated for predicting the nature of adsorption. According to the experimental results, activated carbon prepared from tobacco residue seems to be an effective, low-cost and alternative adsorbent precursor for the removal of phenol from aqueous solutions. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Acid, Activated Carbon, Adsorbents, Adsorption, Biomass, Biosorbent, Biosorption, Cr(VI), Equilibrium, Equilibrium Isotherms, Freundlich, Isotherm, Isotherms, Kinetic, Kinetic Models, Kinetics, KOH, Langmuir, Mechanism, pH, Phenol, Sorption, Thermodynamic, Thermodynamic Parameters, Thermodynamics, Tobacco

? Yi, X.S., Shi, W.X., Yu, S.L., Wang, Y., Sun, N., Jin, L.M. and Wang, S. (2011), Isotherm and kinetic behavior of adsorption of anion polyacrylamide (APAM) from aqueous solution using two kinds of PVDF UF membranes. Journal of Hazardous Materials, 189 (1-2), 495-501.

Full Text: 2011\J Haz Mat189, 495.pdf

Abstract: To determine the isotherm parameters and kinetic parameters of adsorption of anion polyacrylamide (APAM) from aqueous solution on PVDF ultrafiltration membrane (PM) and modified PVDF ultrafiltration membrane (MPM) is important in understanding the adsorption mechanism of ultrafiltration processes. Effect of variables including adsorption time, initial solution concentration, and temperature were investigated. The Redlich-Peterson equation of the five different isotherm models we chose was the most fitted model, and the R(2) was 0.9487, 0.9765 for PM and MPM, respectively; while, the pseudo-first-order model was the best choice among all the four kinetic models to describe the adsorption behavior of APAM onto membranes, suggesting that the adsorption mechanism was a chemical and physical combined adsorption on heterogeneous surface. The thermodynamic parameters were also calculated from the temperature dependence (Delta(r)G(m)(theta), Delta(r)H(m)(theta), Delta(r)S(m)(theta)), which showed that the process of adsorption is not spontaneous but endothermic process and high temperature favors the adsorption. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Mechanism, Behavior, Copolymer, Isotherm, Isotherm Models, Kinetic, Kinetic Models, Manganese Oxide, Mechanism, Membranes, Microfiltration Membranes, Mode, Model, Modified, Polymers, Protein-Adsorption, Pseudo-First-Order, Removal, Surface, Thermodynamic Parameters, UF Membranes, Ultrafiltration, Ultrafiltration Membranes, Waste-Water

? Narayanan, K.B. and Sakthivel, N. (2011), Synthesis and characterization of nano-gold composite using Cylindrocladium floridanum and its heterogeneous catalysis in the degradation of 4-nitrophenol. Journal of Hazardous Materials, 189 (1-2), 519-525.

Full Text: 2011\J Haz Mat189, 519.pdf

Abstract: Greener synthesis of nanogold-biocomposite by fungus, Cylindrocladium floridanum was reported in this study. Results revealed that when cultured in static condition for a period of 7 d, the fungus accumulated gold nanoparticles on the surface of the mycelia. Bionanocomposites with Au nanocrystals were characterized by UV-Vis spectroscopy, XRD, SEM, EDX and high-resolution TEM. The SPR band of UV-Vis spectrum at 540 nm confirmed the presence of gold nanoparticles on the surface of the fungal mycelia. The fcc (1 1 1)-oriented crystalline nature of particles was identified by XRD pattern. The synthesized particles are spherical in shape as evidenced by TEM image. The biocomposites with Au nanoparticles function as an efficient heterogeneous catalyst in the degradation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP), in the presence of reducing agent, sodium borohydride which was reflected by UV-Vis spectra of the catalytic reaction kinetics. The reduction of 4-nitrophenol follows pseudo-first-order kinetic model with the reaction rate constant of 2.67 x 10(-2) min(-1) with 5.07 x 10(-6) mol/dm(3) of gold at ca. 25 nm. The rate of the reaction was increased by increasing the concentration of gold nanoparticles from 2.54 x 10(-6) to 12.67 x 10(-6) mol/dm(3) (similar to 25 nm) and with reduced size from 53.2 to 18.9 nm respectively. This is the first report on fungal-matrixed gold(0) nanocomposites heterogeneously catalyzing the reduction of the toxic organic pollutant, 4-nitrophenol that enable the recovery and recycling of AuNPs catalysts. (C) 2011 Elsevier B.V. All rights reserved.

Keywords: 4-Nitrophenol, Aromatic Nitro-Compounds, Au Nanoparticles, Bioreduction, Biosorption, Biosynthesis, Catalyst, Characterization, Cylindrocladium Floridanum, Kinetic, Kinetic Model, Kinetics, Metal, Model, Nanocomposite, Nanoparticle, Pseudo-First Order Kinetics, Pseudo-First-Order, Rate Constant, Recovery, Reduction, Silver Nanoparticles, Size-Selective Catalysis, Spectroscopic Characterization, Synthesis, XRD

? Zhao, X.D., Song, L.Z., Fu, J., Tang, P. and Liu, F. (2011), Adsorption characteristics of Ni(II) onto MA-DTPA/PVDF chelating membrane. Journal of Hazardous Materials, 189 (3), 732-740.

Full Text: 2011\J Haz Mat189, 732.pdf

Abstract: The melamine-diethylenetriaminepentaacetic acid/polyvinylidene fluoride (MA-DTPA/PVDF) chelating membrane bearing polyaminecarboxylate groups was prepared for the removal of Ni(II) from wastewater effluents. The membrane was characterized by SEM, (13)C NMR and FTIR techniques. Quantitative adsorption experiments were performed in view of pH, contact time, temperature, the presence of Ca(II) and lactic acid as the controlling parameters. Adsorption kinetics and equilibrium were examined regarding the single Ni(II) system, binary Ni(II) and Ca(II) system and nickel-lactic acid complexes system. The desorption efficiency was also evaluated, and the adsorption mechanism was suggested based on experimental data. The results show that the sorption kinetics fit well to Lagergren second-order equation and the isotherms can be well described by Langmuir model. At 298 K, the second-order rate constant is calculated to be 4.171, 11.39, 6.203 cm(2)/(mg min) and the equilibrium uptake is 0.0264, 0.0211 and 0.0216 mg/cm(2) in the aforementioned three systems. The distribution coefficient of Ni(II) slowly decreases from 4.27 to 2.72, and the separation factor (f(Ni(II)/Ca(II))) increases from 3.10 to 8.46 when the initial Ca(II) concentration varies from 20 to 200 mg/L. This reveals the chelating membrane shows more affinity for Ni(II) than Ca(II) ions. In the studied range of lactic acid concentration, Ni(II) uptake decreases with the maximum ratio of 10%. Chemical bonding (chelation) dominates in the adsorption process, and the negative Delta G degrees and Delta H degrees indicate the spontaneous and exothermic nature of adsorption. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.

Keywords: Adsorption, Adsorption Kinetics, Adsorption Mechanism, Aqueous-Solution, Bonding, Cations, Copper(II), Copyright, Desorption, Equilibrium, Experimental, Extraction, Fluoride, Ftir, Heavy-Metals Removal, Ions, Isotherm, Isotherms, Kinetics, Langmuir Model, Mechanism, Mesoporous Silica, Model, Nickel-Organic Complexes, NMR, Parameters, pH, PVDF Chelating Membrane, Rate Constant, Ratio, Removal, Sawdust, Soils, Sorption, Sorption Kinetics, Uptake, Waste-Water, Wastewater

? Xiong, L., Chen, C., Chen, Q. and Ni, J.R. (2011), Adsorption of Pb(II) and Cd(II) from aqueous solutions using titanate nanotubes prepared via hydrothermal method. Journal of Hazardous Materials,