Personal Research Database

179 (1-3), 721-728.

Full Text: 2010\J Haz Mat179, 721.pdf

Abstract: Batch experiments were conducted to assess the effects of Cu(II) and Zn(II) on the biosorption of Pb(II) ions by fresh tissues of Myriophyllum spicatum. The biosorption of Pb(II) was examined for single, binary and ternary solutions at different initial concentrations and different pH values. The experimental results showed that the biosorption capacity increased with increasing pH from 2.0 to 6.0. Both Cu(II) and Zn(II) ions were found to have an adverse effect on the biosorption of Pb(II). The biosorption equilibrium data for single-metal solution were fitted to three isotherm models: Langmuir, Freundlich and Sips, and the Sips isotherm model gave the best fit for the experimental data. The maximum biosorption of Pb(II) in Pb-Cu binary system decreased with increasing concentration of copper ions, and the biosorption equilibrium data for the binary metal solution fitted the Langmuir competitive model well. Comparison between biosorption of Pb(II) and Cu(II) by M. spicatum in the binary solution could lead to the conclusion that the biosorbent (M. spicatum) has no preference of Pb(II) over Cu(II). Fourier transform infrared (FT-IR) spectroscopy was used to characterize the interaction between M. spica turn and Pb(II) ions. The results revealed that the carboxyl, hydroxyl and carbonyl groups are the main binding sites for Pb(II). (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Aquatic Plant, Aqueous-Solutions, Biosorption, By-Products, Cadmium(II), Competitive Biosorption, Copper, Equilibrium, Heavy-Metals, Ions, Isotherm, Kinetics, Langmuir, Langmuir Competitive Model, Lead, Pb(II), Pb(II) Ions, Removal, Single-Component

? Xia, Q.B., Li, Z., Xiao, L.M., Zhang, Z.J. and Xi, H.X. (2010), Effects of loading different metal ions on an activated carbon on the desorption activation energy of dichloromethane/trichloromethane. Journal of Hazardous Materials, 179 (1-3), 790-794.

Full Text: 2010\J Haz Mat179, 790.pdf

Abstract: The effects of loading Fe3+, Mg2+, Cu2+ or Ag+ on activated carbons (ACs) on interaction of the carbon surfaces with dichloromethane (DCM) and trichloromethane (TCM) were investigated. Temperature-programmed desorption (TPD) experiments were conducted to measure the desorption activation energy of DCM/TCM on the ACs separately doped with ions Fe3+, Mg2+, Cu2+ and Ag+. The absolute hardness and electronegativity of DCM and TCM were estimated on the basis of density functional theory. The influence of loading the metal ions on the ACs on the interaction of its surfaces with DCM/TCM was discussed. Results showed that the desorption activation energy of DCM and TCM on the modified ACs followed the order: Fe(III)/AC>Mg(II)/AC>Cu(II)/AC>AC>Ag(I)/AC. Both DCM and TCM were hard base. The loading of ion Fe3+ or Mg2+ on the surface of the ACs enhanced the interaction between DCM/TCM and the surfaces due to Fe3+ and Mg2+ being hard acid, while the loading of ion Ag+ on the surface of the AC weakened the interaction between DCM/TCM and the carbon surfaces due to Ag+ being soft acid. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Density Functional, Density-Functional, Desorption, Desorption Activation Energy, Dichloromethane, Hardness, HSAB Concept, HSAB Principle, Interaction, Metal Ions, Surfaces, TPD, TPD Technique, Trichloromethane

? Cáceres, L., Escudey, M., Fuentes, E. and Báez, M.E. (2010), Modeling the sorption kinetic of metsulfuron-methyl on Andisols and Ultisols volcanic ash-derived soils: Kinetics parameters and solute transport mechanisms. Journal of Hazardous Materials, 179 (1-3), 795-803.

Full Text: 2010\J Haz Mat179, 795.pdf

Abstract: Metsulfuron-methyl sorption kinetic was studied in Andisol and Ultisol soils in view of their distinctive physical and chemical properties: acidic pH and variable surface charge. Different kinetic models were applied to the experimental results. The pseudo-second-order model fitted sorption kinetics data better than the pseudo-first-order model. The rate constant and the initial rate constant values obtained through this model demonstrated the different behavior of metsulfuron-methyl in both kinds of soils, both parameters being the highest for Andisol. The application of Elovich equation, intraparticle diffusion model and a two-site nonequilibrium model (TSNE) allowed to conclude that: (i) the high organic matter content is the governing factor for Andisols where mass transfer across the boundary layer, and in a lesser degree, intraparticle diffusion were the two processes controlling sorption kinetic and (II) the mineral composition was more relevant in Ultisols where rate was controlled almost exclusively by intraparticle diffusion into macropores and micropores. The slower sorption rate on Ultisols, the mechanism involved and the lower sorption capacity of this kind of soils must be taken into account to assess leaching behavior of this herbicide. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Activated Carbon, Adsorption, Andisols, Aqueous-Solution, Bensulfuron-Methyl, Bound Residues, Desorption, Diffusion, Diuron, Kinetic, Kinetic Models, Kinetics, Organic-Matter, Pesticide Sorption, Sorption Kinetic, Sulfonylurea Herbicides, Ultisols, Variable Charge Soils

? Goh, K.H., Lim, T.T., Banas, A. and Dong, Z.L. (2010), Sorption characteristics and mechanisms of oxyanions and oxyhalides having different molecular properties on Mg/Al layered double hydroxide nanoparticles. Journal of Hazardous Materials, 179 (1-3), 818-827.

Full Text: 2010\J Haz Mat179, 818.pdf

Abstract: The sorption ability of fast-coprecipitated and hydrothermally-treated Mg/Al layered double hydroxide nanoparticles (FCHT-LDH) for various oxyhalides and oxyanions was evaluated. Interactions of oxyhalide such as monovalent bromate or oxyanions such as divalent chromate and divalent vanadate with FCHT-LDH were investigated using a combination of macroscopic (batch sorption/desorption studies and electrophoretic mobility (EM) measurements) and microscopic techniques (CHNS/O, XRD, FUR. XPS, and EXAFS analyses). The sorption studies on various oxyanions and oxyhalides suggested that their sorption characteristics on FCHT-LDH were largely governed by their ionic potentials and molecular structures. Oxyanions which have ionic potentials higher than 7 nm(-1) were found to be more readily sorbed by FCHT-LDH than oxyhalides with ionic potentials lower than 5 nm(-1). The results obtained also demonstrated that trigonal pyramid oxyhalides showed a lower degree of specificity for FCHT-LDH than the tetrahedral coordinated oxyanions. From the macroscopic and microscopic studies, monovalent oxyhalide sorption on FCHT-LDH was postulated to occur mainly via anion exchange mechanism with subsequent formation of outer-sphere surface complexes. For polyvalent oxyanion sorption on FCHT-LDH, the mechanisms were possibly associated with both anion exchange and ligand exchange reactions, resulting in the coexistence of outer-sphere and inner-sphere surface complexes. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Anion Exchange, Arsenate, Batch, Chromate, Desorption, EXAFS, Hydrotalcite, Layered Double Hydroxide, Mobility, Nanoparticles, Oxyanion, Oxyhalide, Perchlorate, Phosphate, Removal, Retention, Sorption, Waste-Water, XPS, XRD

? Borowiak-Resterna, A., Cierpiszewski, R. and Prochaska, K. (2010), Kinetic and equilibrium studies of the removal of cadmium ions from acidic chloride solutions by hydrophobic pyridinecarboxamide extractants. Journal of Hazardous Materials, 179 (1-3), 828-833.

Full Text: 2010\J Haz Mat179, 828.pdf

Abstract: Liquid-liquid extraction of cadmium(II) from acidic chloride solutions was carried out with alkyl derivatives of pyridinecarboxamide in toluene with addition of 2-ethylhexan-1-ol as modifier. Equilibrium as well as kinetic studies was performed. The kinetic studies of a Cd(II) extraction process were carried out with a Lewis cell having a constant interfacial area. Cadmium(II) concentration in the aqueous phases was determined by atomic absorption spectroscopy (Varian SPECTRAA800). The results of equilibrium experiments showed that cadmium(II) was quantitatively extracted with N,N-dihexylpyridine-3-carboxamide whereas the derivative N,N-dihexylpyridine-2-carboxamide was not able to transfer Cd(II) ions from the aqueous phase to the organic one. Thus, the kinetics of extraction and the initial extraction rate were examined only in the systems with N,N-dihexylpyridine-3-carboxamide. The obtained experimental data as well as the calculated values of mass transfer coefficients suggest that the investigated process of extraction of Cd(II) by means of pyridinecarboxamide as extractant occurs in the mixed diffusion-kinetic region. Moreover, the results of adsorption studies indicated that the extraction of Cd(II) with a hydrophobic extractant should be considered as an interfacial process. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Cadmium, Cadmium(II), Carriers, Cd(II), Cobalt, Copper(II), Cyanex-923, Derivatives, Equilibrium, Extraction Modifier, Kinetic, Kinetics, Lewis-Type Cell, Liquid-Liquid-Extraction, Mass Transfer, Mass Transfer Coefficient, Membrane, N,N-Dialkylpyridine-3-Carboxamide, Removal, Solvent-Extraction, System, Toluene, Transport

? Yang, H., An, T.C., Li, G.Y., Song, W.H., Cooper, W.J., Luo, H.Y. and Guo, X.D. (2010), Photocatalytic degradation kinetics and mechanism of environmental pharmaceuticals in aqueous suspension of TiO₂: A case of beta-blockers. Journal of Hazardous Materials, 179 (1-3), 834-839.

Full Text: 2010\J Haz Mat179, 834.pdf

Abstract: This study investigated the photocatalytic degradation of three beta-blockers in TiO2 suspensions. The disappearance of the compounds followed pseudo-first-order kinetics according to the Langmuir-Hinshelwood model and the rate constants were 0.075, 0.072 and 0.182 min(-1) for atenolol, metoprolol and propranolol, respectively. After 240 min irradiation, the reaction intermediates were completely mineralized to CO2 and the nitrogen was predominantly as NH4+. The influence of initial pH and beta-blocker concentration on the kinetics was also studied. From adsorption studies it appears that the photocatalytic degradation occurred mainly on the surface of TiO2. Further studies indicated that surface reaction with (OH)-O-center dot radical was principally responsible for the degradation of these three beta-blockers. The major degradation intermediates were identified by HPLC/MS analysis. Cleavage of the side chain and the addition of the hydroxyl group to the parent compounds were found to be the two main degradation pathways for all three beta-blockers. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Active Compounds, Adsorption, Advanced Oxidation Processes, Analysis, Aquatic Environment, Beta-Blocker, Chromatography, CO₂, Compounds, Degradation, Drugs, HPLC, MS, Kinetics, Mass-Spectrometry, Mechanism, pH, Photocatalytic Degradation, Reactive Oxygen Species, Removal, Sewage-Treatment Plants, TiO₂, Transformations, Waste-Water

? Chen, B.L., Wang, Y.S. and Hu, D.F. (2010), Biosorption and biodegradation of polycyclic aromatic hydrocarbons in aqueous solutions by a consortium of white-rot fungi. Journal of Hazardous Materials, 179 (1-3), 845-851.

Full Text: 2010\J Haz Mat179, 845.pdf

Abstract: Bioremediation is a popular approach used to abate polycyclic aromatic hydrocarbons (PAHs) in the environment. A consortium of white-rot fungi (CW-1) isolated from wood pieces was used for studying their potential of bioremediation of PAHs. Biosorption and biodegradation of PAHs by live and heat-killed white-rot fungi (CW-1) were investigated to elucidate the bio-dissipation mechanisms of PAHs. Sorption isotherms of naphthalene, acenaphthene, fluorene, phenanthrene and pyrene to heat-killed fungal biomass were linear and non-competitive, indicating the primary mechanism of biosorption to be by partition. The carbon-normalized partition coefficients (K-oc) were linearly correlated with octanol-water partition coefficients (K-ow), i.e., logK(oc) = 1.13 logK(ow) -0.84 (n = 5, r(2) = 0.996). Biosorption and biodegradation of phenanthrene and pyrene by live white-rot fungi were quantified. In 1 week, the removal efficiency of phenanthrene (70-80%) and pyrene (90%) by live fungi from aqueous solution were comparable to those by heat-killed fungi. However, approximately 40-65% of phenanthrene and 60-85% of pyrene were still stored in organismal bodies. Biosorption might restrict biodegradation while nutrient limitation and presence of a PAH mixture might stimulate biodegradation. The apparent partition coefficients (K-d(+)) in live fungal systems and the K-d of heat-killed fungi without biodegradation were compared, and then the K-d(+)/K-d ratios were employed to illustrate the relative contributions of biosorption and biodegradation under different nutrient conditions. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Aqueous Solutions, Biodegradation, Biomass, Bioremediation, Biosorption, China, Degradation, Isotherms, Naphthalene, Nutrient Limitation, Organic Pollutants, Plant, Polycyclic Aromatic Hydrocarbons, Removal, Sediments, Soil, Sorption, Sorption Isotherms, White-Rot Fungi

? Choi, H. and Al-Abed, S.R. (2010), Effect of reaction environments on the reactivity of PCB (2-chlorobiphenyl) over activated carbon impregnated with palladized iron. Journal of Hazardous Materials, 179 (1-3), 869-874.

Full Text: 2010\J Haz Mat179, 869.pdf

Abstract: Reactive activated carbon (RAC) impregnated with palladized iron nanoparticles has been developed to treat polychlorinated biphenyls (PCBs). In this study, we evaluated the effects of various reaction environments on the adsorption-mediated dechlorination of 2-chlorobiphenyl (2-CIBP) in the RAC system. The results were discussed in close connection to the implementation issue of the RAC system for the remediation of contaminated sites with PCBs. Adsorption event of 2-CIBP onto RAC limited the overall performance under condition with a 2-CIBP/RAC mass ratio of less than 1.0 x 10(-4) above which dechlorination of 2-CIBP adsorbed to RAC was the reaction rate-determining step. Acidic and basic conditions were harmful to 2-CIBP adsorption and iron stability while neutral pH showed the highest adsorption-promoted dechlorination of 2-CIBP and negligible metal leaching. Coexisting natural organic matter (NOM) slightly inhibited 2-CIBP adsorption onto RAC due to the partial partitioning of 2-CIBP into NOM in the liquid phase while the 2-CIBP absorbed into NOM, which also tended to adsorb onto RAC, was less available for the dechlorination reaction. Common anions slowed down 2-CIBP adsorption but adsorbed 2-CIBP was almost simultaneously dechlorinated. Some exceptions included strong inhibitory effect of carbonate species on 2-CIBP adsorption and severe detrimental effect of sulfite on 2-CIBP dechlorination. Results on treatment of 2-CIBP spiked to actual sediment supernatants implied site-specific reactivity of RAC. Published by Elsevier B.V.

Keywords: Activated Carbon, Adsorption, Barrier, Catalysts, Corrosion, Fe, Pd, Groundwater, Implementation Issue, Nanoparticles, NOM, Oxidation, Palladized Iron, pH, Polychlorinated Biphenyls, Reaction Environments, Reactive Activated Carbon, Reduction, Remediation, Sediment, System, TCE Dechlorination, Treatment, Zero-Valent Iron

? Quan, C., Li, A.M. and Gao, N.B. (2010), Synthesis of carbon nanotubes and porous carbons from printed circuit board waste pyrolysis oil. Journal of Hazardous Materials, 179 (1-3), 911-917.

Full Text: 2010\J Haz Mat179, 911.pdf

Abstract: The possibility and feasibility of using pyrolysis oil from printed circuit board (PCB) waste as a precursor for advanced carbonaceous materials is presented. The PCB waste was first pyrolyzed in a laboratory scale fixed bed reactor at 600 degrees C to prepare pyrolysis oil. The analysis of pyrolysis oil by gas chromatography-mass spectroscopy indicated that it contained a very high proportion of phenol and phenol derivatives. It was then polymerized in formaldehyde solution to synthesize pyrolysis oil-based resin which was used as a precursor to prepare carbon nanotubes (CNTs) and porous carbons. Scanning electron microscopy and transmission microscopy investigation showed that the resulting CNTs had hollow cores with outer diameter of similar to 338 nm and wall thickness of similar to 86 nm and most of them were filled with metal nanoparticles or nanorods. X-ray diffraction reveals that CNTs have an amorphous structure. Nitrogen adsorption isotherm analysis indicated the prepared porous carbons had a Brunauer-Emmett-Teller surface area of 1214 m(2)/g. The mechanism of the formation of the CNTs and porous carbons was discussed. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Activated Carbons, Adsorption, Adsorption Isotherm, Analysis, Carbon Nanotubes, CNTS, Isotherm, Membrane, Nanoparticles, PCB Waste Pyrolysis Oil, Phenol, Phenol-Formaldehyde Resin, Porous Carbons, Precursors, Resource Utilization, X-Ray Diffraction

? Kaušpėdienė, D., Kazlauskienė, E., Gefenienė, A. and Binkienė, R. (2010), Comparison of the efficiency of activated carbon and neutral polymeric adsorbent in removal of chromium complex dye from aqueous solutions. Journal of Hazardous Materials, 179 (1-3), 933-939.

Full Text: 2010\J Haz Mat179, 933.pdf

Abstract: The removal efficiency of chromium complex dye Lanasyn Navy M-DNL from aqueous solution using the activated carbon (AC) and the neutral polymeric adsorbent Macronet MN 200 (MN 200) has been investigated under various experimental conditions: initial dye concentration, pH and temperature. The effectiveness of MN 200 for the dye removal was found relatively higher than that of AC in both acidic and neutral solutions. Two theoretical models (pseudo-second-order-reaction and intraparticle diffusion) were used to describe the sorption kinetics, and to determine the constants of sorption rate (k(2)), intraparticle (k(i)) and film diffusion (k(s)). The both sorption systems dye-AC and dye-MN 200 follow the pseudo-second-order model with a higher k(2) value for dye-MN 200 in acidic media at 20°C when compared with that of the dye-AC. With increase in the solution temperature from 20 to 40°C the k(2) value for dye-AC indicate an increase in acidic media and decrease in alkaline media; whereas k(2) values for dye-MN 200 decrease in both acidic and neutral media. The rate of dye adsorption on both adsorbents is dependent on intraparticle and film diffusion proceeding simultaneously. The boundary layer effect is more pronounced in acidic solutions and with increase in temperature. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Acid-Blue-193, Activated Carbon, Adsorbent, Adsorption, Anion-Exchangers, Basic Activated Carbon, Chromium Complex Dye, Diffusion, Dye, Effluent, Hyper-Cross-Linked Polystyrene, Kinetic, Kinetics, Polystyrene, Reactive Dyes, Removal, Sepiolite, Sorbents, Sorption

? Ribeiro, R.F.L., Magalhaes, S.M.S., Barbosa, F.A.R., Nascentes, C.C., Campos, I.C. and Moraes, D.C. (2010), Evaluation of the potential of microalgae Microcystis novacekii in the removal of Pb²⁺ from an aqueous medium. Journal of Hazardous Materials, 179 (1-3), 947-953.

Full Text: 2010\J Haz Mat179, 947.pdf

Abstract: In this study, the absorption capacity of active and inactive biomass of the microalgae Microcystis novacekii to remove Pb2+ from aqueous solutions was investigated. This is the first reported study of biosorption by a cyanobacterium species, which is abundant and easily found in eutrophic lakes and ponds in tropical areas of the world. We also evaluated the effects of different concentrations of Pb2+ on growth rates of M. novacekii. Inactive biomass was characterized by elemental composition, surface area, potentiometric titration, infrared spectroscopy and thermogravimetric analysis (TGA). The biosorption data of Pb2+ by inactive biomass were analyzed using the Langmuir and Freundlich isotherms. Pb2+ concentrations higher than 0.5 mg L-1 inhibited species growth. Potentiometric titrations showed a significantly higher negative surface charge (1.48 +/- 0.22 mmol g(-1)) with two acidic groups (pKa(1) = 3.74 +/- 0.12 and, pKa(2) = 7.25 +/- 0.30). Analysis of inactive M. novacekii cells by infrared spectroscopy suggests that the cell wall carboxyl and amide groups participate in Pb2+ biosorption. The maximum Pb2+ adsorbed was found to be 70 mg g(-1), and the biosorption of Pb2+ on inactive M. novacekii correlated well (R-2 = 0.931) with the Langmuir equation compared to the Freundlich isotherm equation (R-2 = 0.823) in the concentration range studied. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorption, Analysis, Aqueous Solutions, Aspergillus-Niger, Biomass, Biosorbent Characterization, Biosorption, Brown Alga, Copper, Equilibrium, Freundlich, Freundlich Isotherm, Green-Algae, Heavy-Metal Biosorption, Infrared, Isotherm, Isotherms, Langmuir, Langmuir And Freundlich Isotherms, Lead Biosorption, Microcystis Novacekii, Pb²⁺, Removal, Titration, Toxicity

? Hwang, G., Lee, C.H., Ahn, I.S. and Mhin, B.J. (2010), Analysis of the adhesion of Pseudomonas putida NCIB 9816-4 to a silica gel as a model soil using extended DLVO theory. Journal of Hazardous Materials, 179 (1-3), 983-988.

Full Text: 2010\J Haz Mat179, 983.pdf

Abstract: The extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory was applied to explain the hydrophobic interaction-mediated adhesion of Pseudomonas putida NCIB 9816-4 to soil. Soil particles are heterogeneous, and it is difficult to define consistent physico-chemical properties such as a contact angle and zeta potential. Hence, a silica gel and a silanized (3-aminopropyltriethoxysilane-coated) silica gel, which showed greater hydrophobicity than the unmodified silica gel, were used as model soils. Gibbs energies for the cell adhesion to the silica gels were calculated with the physico-chemical properties of the microbes and the silica gels and then plotted as a function of the separation distance. The extended DLVO theory successfully explained that the adhesion of P. putida NCIB 9816-4 to the silica gel, a model soil, was primarily caused by hydrophobic interaction. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adhesion, Adsorption, Bacteria, Biodegradation, Components, Deposition, Extended Dlvo Theory, Forces, Hydrophobic Interaction, Mechanisms, NCIB-9816-4, Pseudomonas Putida, Silica, Silica Gel, Soil, Soils, Stability, Surface Free-Energy, Zeta Potential

? Sahu, R.C., Patel, R. and Ray, B.C. (2010), Utilization of activated CO₂-neutralized red mud for removal of arsenate from aqueous solutions. Journal of Hazardous Materials, 179 (1-3), 1007-1013.

Full Text: 2010\J Haz Mat179, 1007.pdf

Abstract: A laboratory study was conducted to investigate the ability of activated CO₂-neutralized red mud (ANRM) for the removal of arsenate from the aqueous solutions. The batch adsorption experiments were conducted with respect to adsorbent dose, equilibrium pH, contact time, initial arsenate concentration, kinetics, Langmuir isotherms. The mechanisms involved in adsorption of arsenate ions on ANRM were characterized by using XRD, FT-IR, UV-vis, SEM/EDX, and chemical methods. The percentage removal was found to increase gradually with decrease of pH and maximum removal was achieved at pH similar to 4. Adsorption kinetic studies revealed that the adsorption process followed pseudo-second-order kinetics and equilibrates within 24 h. FT-IR spectra of ANRM before and after adsorption reveals the binding of arsenate to the adsorbent. The adsorption data were fitted to linearly transformed Langmuir isotherm with R² (correlation coefficient) > 0.99. Arsenate adsorbed ANRM can be regenerated using NaOH solution at pH 12.0. (C) 2010 Elsevier B.V. All rights reserved.

Keywords: Adsorbent, Adsorption, Arsenate, CO₂, Desorption, Equilibrium, Ferrihydrite, Hydroxide, Iron, Isotherm, Isotherms, Kinetic, Kinetics, Langmuir, Langmuir Isotherm, Oxidation, Phosphate, Public-Health, Red Mud, Surface, Water

? Deng, S.B., Li, Z.J., Huang, J. and Yu, G. (2010), Preparation, characterization and application of a Ce-Ti oxide adsorbent for enhanced removal of arsenate from water. Journal of Hazardous Materials,