Personal Research Database

Full Text: W\Wat Res36, 4870.pdf

Abstract: The transport through polymer inclusion membranes (PIMs) was found as the effective and selective method of chromium(VI) anions removal from chloride acidic aqueous solutions. The optimal PIMs content was as follows: 41wt% of cellulose triacetate as the support, 23wt% of tri-n-octylamine as the ionic carrier, and 36wt% of o-nitrophenyl pentyl ether as the plasticizer. The results obtained show a linear decrease of permeability coefficient and initial flux values with source phase pH increase. Also linear decrease of initial flux in log–log scale with chromium(VI) concentration increase was observed. Value of slope of this relationship was found to be 0.96 which indicates a first order of chromium(VI) reaction with tri-n-octylamine at membrane/aqueous source interface. Transport of chromium(VI) through PIMs reduces the concentration of chromium(VI) in source aqueous phase from 1.0 to 0.0028 ppm, which is below permissible limit in drinking water in Poland. Competitive transport of chromium(VI), cadmium(II), zinc(II), and iron(III) from acidic aqueous solution across PIMs was found to be efficient for chromium(VI) (99%), and cadmium(II) (99%). (C) 2002 Elsevier Science Ltd. All rights reserved.

Keywords: Chromium(VI), Tri-n-Octylamine, Polymer Inclusion Membrane, Waste Water Treatment

Lai, C.H., Chen, C.Y., Wei, B.L. and Yeh, S.H. (2002), Cadmium adsorption on goethite-coated sand in the presence of humic acid. Water Research, 36 (20), 4943-4950.

Full Text: W\Wat Res36, 4943.pdf

Abstract: Heat was employed to coat crystalline goethite onto a quartz sand surface so that the adsorbent properties of the coating could be utilized. The adsorption characteristics of cadmium and humic acid onto goethite-coated sand were examined. Results show that the goethite-coated sand surface had a higher specific surface area and more mesopores than the uncoated sand. The adsorption of both cadmium and humic acid was highly pH-dependent: cadmium adsorption increased with pH, but humic acid adsorption decreased as pH increased. The presence of humic acid resulted in increasing cadmium adsorption in a specific pH range. The order of reacting humic acid with cadmium was found to have a noticeable effect on the final adsorption capacity. The adsorption capacity of cadmium for humic acid that is adsorbed onto goethite-coated sand before reacting with a cadmium system, exceeds that of humic acid that is mixed with cadmium ions before goethite-coated sand is added.

Keywords: Adsorption, Cadmium, Coating, EDAX, Goethite, Humic Acid

Nishi, Y., Iwashita, N., Sawada, Y. and Inagaki, M. (2002), Sorption kinetics of heavy oil into porous carbons. Water Research, 36 (20), 5029-5036.

Full Text: W\Wat Res36, 5029.pdf

Abstract: Sorption kinetics of heavy oil into porous carbons was evaluated by a concept of liquid sorption coefficient obtained from the weight increase of heavy oil with sorption time, which was measured by a wicking test. Exfoliated graphite, carbonized fir fibers and carbon fiber felts were used as porous materials. It was found that the liquid sorption coefficient of fibrous carbons was twice larger than that of exfoliated graphite. Such a difference in the liquid sorption coefficient between the exfoliated graphite and two fibrous carbons was caused by a difference in effective sorption porosity and tortuosity between them. For the exfoliated graphite and carbonized fir fibers, the liquid sorption coefficient and the effective sorption porosity were strongly dependent on their density. The maximum values of both liquid sorption coefficient and effective sorption porosity of the exfoliated graphite were shown at the bulk density around 16 kg/m³. The liquid sorption coefficient of the carbonized fir fibers increased with increasing the density in the range from 6 to 30 kg/m³. When the carbonized fir fibers were densified above 30 kg/m³, the sorption rate was saturated. On the other hand, the sorption kinetics into the carbon fiber felt was almost independent of the bulk density, because the density of the carbon fiber felt is not effective for the pore structure. The effect of bulk density on the sorption kinetics could be supported from an analysis of pore structure of the porous carbons with different densities, which was measured by mercury porosimeter.

Keywords: Sorption Kinetics, Heavy Oil Recovery, Porous Carbon, Wicking Test, Liquid Sorption Coefficient, Effective Sorption Porosity

Katsoyiannis, I.A. and Zouboulis, A.I. (2002), Removal of arsenic from contaminated water sources by sorption onto iron-oxide-coated polymeric materials. Water Research, 36 (20), 5141-5155.

Full Text: W\Wat Res36, 5141.pdf

Abstract: The modification of polymeric materials (polystyrene and polyHIPE) by coating their surface with appropriate adsorbing agents (i.e. iron hydroxides) was investigated in the present work, in order to apply the modified media in the removal of inorganic arsenic anions from contaminated water sources. The method, termed adsorptive filtration, has been classified as an emerging technology in water treatment processes as it presents several advantages towards conventional technologies: the production of high amounts of toxic sludge can be avoided and it is considered as economically more efficient; whereas it has not yet been applied in full-scale treatment plants for low-level arsenic removal. The present experiments showed that both modified media were capable in removing arsenic from the aqueous stream, leading to residual concentration of this toxic metalloid element below 10 g/L, which is the new maximum concentration limit set recently by the European Commission and imposed by the USEPA. Though, among the examined materials, polyHIPE was found to be more effective in the removal of arsenic, as far as it concerns the maximum sorptive capacity before the filtration bed reaches the respective breakthrough point. (C) 2002 Elsevier Science Ltd. All rights reserved.

Keywords: Arsenic, Drinking Water, Iron Oxides, Polymeric Materials, Upflow Filtration, Drinking-Water, Adsorption, Coagulation, Filtration, Sand, Mechanism, Goethite, Metals, As(V)

DeMarco, M.J., Sengupta, A.K. and Greenleaf, J.E. (2003), Arsenic removal using a polymeric/inorganic hybrid sorbent. Water Research, 37 (1), 164-176.

Full Text: W\Wat Res37, 164.pdf

Abstract: A fixed-bed sorption process can be very effective in removing trace concentrations of arsenic from contaminated groundwater provided: the sorbent is very selective toward both As(III) and As(V) species; the influent and treated water do not warrant any additional pre- or post- treatment; pH and composition of the raw water with respect to other electrolytes remain unchanged besides arsenic removal, and the sorbent is durable with excellent attrition resistance properties. In addition, the sorbent should be amenable to efficient regeneration for multiple reuse. This study reports the results of an extensive investigation pertaining to arsenic removal properties of a polymeric/inorganic hybrid sorbent. Each hybrid sorbent particle is essentially a spherical macroporous cation exchanger bead within which agglomerates of nanoscale hydrated Fe oxide (HFO) particles have been uniformly and irreversibly dispersed using a simple chemical-thermal treatment. The new sorbent, referred to as hybrid ion exchanger or HIX, combines excellent mechanical and hydraulic properties of spherical polymeric beads with selective As(III) and As(V) sorption properties of HFO nanoparticles at circum-neutral pH. Comparison of the results of fixed-bed column runs between the new sorbent and the polymeric anion exchanger confirmed that both As(V) and As(III) were removed very selectively with HIX. Equally important, no pH adjustment, pre- or post-treatment was warranted. Besides the absence of arsenic, the treated water composition was identical to that of influent water. HIX was amenable to efficient in situ regeneration with caustic soda and could subsequently be brought into service following a short rinse with carbon dioxide sparged water. During fixed-bed column runs, intraparticle diffusion was identified as the primary rate-limiting step for both As(III) and As(V) sorption. Repeated use of the same HIX particles during various laboratory investigations provided strong evidence that the new sorbent possesses excellent attrition resistance properties and retains its arsenic removal capacity over cycles. (C) 2002 Elsevier Science Ltd. All rights reserved.

Keywords: Arsenic, Sorbent, Ion Exchange, Toxic, Drinking Water, Ion-Exchange, Water-Treatment, Intraparticle Diffusion, Ground-Water, Contaminants, Adsorption, Stability, Sorption

Kara, M., Yuzer, H., Sabah, E. and Celik, M.S. (2003), Adsorption of cobalt from aqueous solutions onto sepiolite. Water Research, 37 (1), 224-232.

Full Text: W\Wat Res37, 224.pdf

Abstract: Adsorption of Co(II) ions from aqueous sepiolite suspensions has been systematically investigated as a function of several variables including activation conditions, solid to liquid ratio, pH and temperature. The results are analyzed to identify the mechanism of cobalt uptake by sepiolite. Both abstraction and real adsorption isotherms were constructed to isolate the precipitation of cobalt from the real adsorption. Also, for the first time a plausible correlation between the released Mg(II) ions from sepiolite matrix and those adsorbed Co(II) ions is made. A one to one ion exchange mechanism is found to describe the results. The data obtained from adsorption isotherms at different temperatures were fitted to various adsorption models to calculate thermodynamic quantities such as the free energy of adsorption, heat of adsorption and entropy of adsorption. The thermodynamic data indicate that Co(II) adsorption onto sepiolite is entropically driven and characterized by physical adsorption.

Keywords: Adsorption, Clay Minerals, Sepiolite, Cobalt, Wastewater Treatment

Haussard, M., Gaballah, I., Kanari, N., de Donato, Ph., Barrès, O. and Villieras, F. (2003), Separation of hydrocarbons and lipid from water using treated bark. Water Research, 37 (2), 362-374.

Full Text: W\Wat Res37, 362.pdf

Abstract: This paper explores the possibility of using treated bark to remove oily compounds from water. Bark was first biologically or chemically treated and saturated with transition metal ions (TMI) to avoid the release of soluble organic compounds from the bark in the treated effluents.

Several experimental parameters affecting the oil removal efficiency (RE) were studied (initial oil concentration, temperature, time. etc.). Saturated bark was characterized using Fourier transform infrared (FTIR) spectroscopy and bark wetting index was determined. Results of the retention of lipids suggested that their removal could exceed 95% of initial oil concentration. The uptake of lipid by treated bark varied from 0.2 to 2.0 g of organic oil/g of dry sorbent. No significant chemical modifications of saturated bark were observed in infrared spectroscope after the sorption of oleic acid on bark treated with transition metal ions. The structure of adsorbed tridimentional layer of oleic acid molecules seemed to take place through the double bond. The hydrocarbon RE exceeded 95% using oil-water mixture with a hydrocarbon/bark ratio of one.

The sorption reaction of hydrocarbons and lipids was quasi-instantaneous and seemed to be influenced by the temperature. This indicated that the retention mechanism was related to the capillary action. Results of FTIR spectroscopy suggested that no chemical bonds between barks and oily compounds were established. (C) 2002 Elsevier Science Ltd. All rights reserved.

Keywords: Acid, Adsorption, Adsorption, Bark, Chemical Modifications, Hydrocarbons, Lipids, Metal, Metal Ions, Oily Wastes, Removal, Sorption, Treated Bark

Wang, L., Chua, H., Zhou, Q., Wong, P.K., Sin, S.N., Lo, W.L. and Yu, P.H. (2003), Role of cell surface components on Cu²⁺ adsorption by Pseudomonas putida 5-x isolated from electroplating effluent. Water Research, 37 (3), 561-568.

Full Text: W\Wat Res37, 561.pdf

Abstract: A Gram-negative bacterium Pseudomonas putida 5-x with high Cu²⁺ accumulating capability was isolated from electroplating effluent in Kwun Tong, Hong Kong. The pretreated cells without superficial layer-capsule, isolated cell envelopes and the separated peptidoglycan layer materials were obtained from fresh P. putida 5-x cells, their Cu²⁺ adsorption capacities and properties were compared with that of the fresh cells. Pretreatment by 0.1 mol L⁻¹ HCl enhanced Cu²⁺ adsorption capacity due to the degradation of cell superficial layer-capsule of P. putida 5-x cells. Isolated cell envelopes possessed five times more Cu²⁺ adsorption capacity than that of fresh intact cell. The Cu²⁺ adsorption of separated peptidoglycan layer materials indicated that the peptidoglycan layer only played 10–15% part of the Cu²⁺ adsorption capacity, and implied other cell surface components such as outer membrane or inner membrane might play an important role in such high Cu²⁺ binding of the cell envelopes. The adsorption process of fresh cells, pretreated cells and cell envelopes of P. putida 5-x could be described with Freundlich isotherm, while the adsorption of Cu²⁺ by separated peptidoglycan layer materials was better described with Langmuir isotherm. (C) 2003 Elsevier Science Ltd. All rights reserved.

Keywords: Adsorption Isotherm, Cell Capsule, Cell Envelopes, Cu²⁺ Adsorption Capacity, Peptidoglycan Layer (PEG), Pseudomonas putida

Pagnanelli, F., Esposito, A., Toro, L. and Vegliò, F. (2003), Metal speciation and pH effect on Pb, Cu, Zn and Cd biosorption onto Sphaerotilus natans: Langmuir-type empirical model. Water Research, 37 (3), 627-633.

Full Text: W\Wat Res37, 627.pdf

Abstract: Biosorption data of lead, copper, zinc and cadmium onto Sphaerotilus natans at different equilibrium pH (3–5 units) were here reported and analysed. Experimental results outlined the positive effect of pH increase on pollutant uptake and also the biomass affinity series (Pb > Cu > Zn > Cd) reflecting the hydrolytic properties of metals. An original empirical model was proposed to represent the effect of pH on heavy metal biosorption inserting q_max vs. pH empirical functions into the classical Langmuir isotherm.

Keywords: Heavy Metal, Biosorption, Speciation, Modelling, Langmuir

Netpradit, S., Thiravetyan, P. and Towprayoon, S. (2003), Application of ‘waste’ metal hydroxide sludge for adsorption of azo reactive dyes. Water Research, 37 (4), 763-772.

Full Text: W\Wat Res37, 763.pdf

Abstract: The capacity and mechanism of metal hydroxide sludge in removing azo reactive dyes from aqueous solution was investigated with different parameters, such as charge amount of dyes, system pH, adsorbent particle size, and adsorbent dosage. The three anionic dyes used were CI Reactive Red 2, CI Reactive Red 120, and CI Reactive Red 141, increasing in number of sulfonic groups, respectively. Only 0.2% (w/v) of powdered sludge (<75 m) achieved color removal from 30 mg l^-1 reactive dye solutions within 5 min without pH adjustment. The larger the charge amount of the dyes, the greater the adsorption (>90%) on the metal hydroxide sludge. The system pH played a significant role in the adsorption on metal hydroxides and formation of dye–metal complexes. The optimum system pH for dye adsorption was 8–9 which was close to the pH_zpc of the sludge while the precipitation of dye–metal complexes occurred at system pH 2. The maximum adsorption capacity (Q°) of the sludge for the reactive dyes was 48–62 mg dye g^-1 adsorbent. The Langmuir and Freundlich models showed that the higher charged dyes had a higher affinity of adsorption. The smaller particle size and the greater amount of adsorbent showed the faster process, due to an increase in surface area of adsorbent. Desorption studies elucidated that metal hydroxide sludge had a tendency for ion exchange adsorption of sulfonated azo reactive dyes. Leaching data showed that the treated water was nontoxic at a system pH above 5 or a solution pH above 2.

Keywords: Adsorption, Desorption, Ion Exchange, Metal Hydroxides, Reactive Dyes

? Li, Q.L., Snoeyink, V.L., Mariaas, B.J. and Campos, C. (2003), Elucidating competitive adsorption mechanisms of atrazine and NOM using model compounds. Water Research, 37 (4), 773-784.

Full Text: 2003\Wat Res37, 773.pdf

Abstract: Based on the relative adsorbability of natural organic matter (NOM) fractions with different molecular weights (MWs), two model compounds, poly(styrene sulfonate) (PSS) (nominal MW = 1800 Dalton) and p-dichlorobenzene (DCB), were chosen to study the competitive effect of large and small NOM molecules on atrazine adsorption by two powdered activated carbons (PACs) with different pore size distributions. Both isotherm and kinetic tests of atrazine adsorption were conducted using fresh PAC and PAC preloaded with the model compounds. The model compounds were found to affect atrazine adsorption through two different mechanisms due to their size difference: direct competition for sites by p-DCB and pore constriction/blockage by PSS-1.8k. p-DCB was found to significantly reduce atrazine adsorption capacity but to have no effect on atrazine adsorption kinetics. In contrast, the effect of PSS-1.8k on atrazine adsorption capacity was very small. Furthermore, during simultaneous adsorption, PSS-1.8k had no effect on atrazine surface diffusion. However, preloading PAC with PSS-1.8k lowered the atrazine surface diffusion coefficient, D-s, by more than three orders of magnitude; D-s decreased with increasing solid phase PSS-1.8k concentration. The pore size distribution of the PAC was found to play an important role in competitive adsorption. A high mesopore surface area could alleviate pore blockage significantly. (C) 2002 Elsevier Science Ltd. All rights reserved.

Keywords: Activated Carbons, Adsorption, Adsorption Kinetics, Aquatic Humic Substances, Atrazine, Capacity, Carbons, Competitive Adsorption, Diffusion, GAC Adsorption, Granular Activated Carbon, Isotherm, Kinetic, Kinetics, Model, Model Compounds, Molecular, Natural, Natural Organic Matter, Natural-Water, Nom, Organic-Matter, PAC, Pore Blockage, Pore Size Distribution, Pore-Size, Powdered Activated Carbon, Science, Size-Exclusion Chromatography, Spectroscopic Properties, Surface Diffusion, TCE Adsorption

Notes: highly cited

Yavuz, Ö., Altunkaynak, Y. and Güzel, F. (2003), Removal of copper, nickel, cobalt and manganese from aqueous solution by kaolinite. Water Research, 37 (4), 948-952.

Full Text: W\Wat Res37, 948.pdf

Abstract: The removal of some heavy metals such as Mn(II), Co(II), Ni(II), and Cu(II) from aqueous solution is studied using a raw kaolinite. The sorption of these metals on kaolinite conformed to linear form of Langmuir adsorption equation. Langmuir C_m constants for each metal were found as 0.446 mg/g (Mn), 0.919 mg/g (Co), 1.669 mg/g (Ni), 10, 787 mg/g (Cu) at 25°C, respectively. Also, kinetic and thermodynamic parameters such as enthalpy (H), free energy (G) and entropy (S) were calculated and these values show that adsorption of heavy metal on kaolinite was an endothermic process and the process of adsorption was favoured at high temperatures.

Keywords: Heavy Metals, Removal, Adsorption, Kaolinite

Notes: highly cited

? von Gunten, U. (2003), Ozonation of drinking water: Part I. Oxidation kinetics and product formation. Water Research, 37 (7), 1443-1467.

Full Text: 2003\Wat Res37, 1443.pdf

Abstract: The oxidation of organic and inorganic compounds during ozonation can occur via ozone or OH radicals or a combination thereof. The oxidation pathway is determined by the ratio of ozone and OH radical concentrations and the corresponding kinetics. A huge database with several hundred rate constants for ozone and a few thousand rate constants for OH radicals is available. Ozone is an electrophile with a high selectivity. The second-order rate constants for oxidation by ozone vary over 10 orders of magnitude, between <0.1 M(-1)s(-1) and about 7 x 10(9) M(-1)s(-1). The reactions of ozone with drinking-water relevant inorganic compounds are typically fast and occur by an oxygen atom transfer reaction. Organic micropollutants are oxidized with ozone selectively. Ozone reacts mainly with double bonds, activated aromatic systems and non-protonated amines. In general, electron-donating groups enhance the oxidation by ozone whereas electron-withdrawing groups reduce the reaction rates. Furthermore, the kinetics of direct ozone reactions depend strongly on the speciation (acid-base, metal complexation). The reaction of OH radicals with the majority of inorganic and organic compounds is nearly diffusion-controlled.

The degree of oxidation by ozone and OH radicals is given by the corresponding kinetics. Product formation from the ozonation of organic micropollutants in aqueous systems has only been established for a few compounds. It is discussed for olefines, amines and aromatic compounds. (C) 2002 Elsevier Science Ltd. All rights reserved.

Keywords: Ozone, Advanced Oxidation, Water Treatment, Kinetics, Micropollutants, Product Formation, Of-the-Art, Ethylenediaminetetraacetic-Acid Edta, Oxygenated Aqueous-Solution, Radical-Induced Oxidation, Disinfection By-Products, Dissociating Organic-Compounds, Rate Constants, Pulse-Radiolysis, Hydroxyl Radicals, Ozone Decomposition

Notes: highly cited

Sun, Q.Y. and Yang, L.Z. (2003), The adsorption of basic dyes from aqueous solution on modified peat-resin particle. Water Research, 37 (7), 1535-1544.

Full Text: W\Wat Res37, 1535.pdf

Abstract: Modified peat was prepared by mixing thoroughly raw peat with sulfuric acid, and modified peat-resin particle was obtained, by mixing modified peat with solutions of polyvinylalcohol (PVA) and formaldehyde. In this paper, the adsorption of Basic Magenta and Basic Brilliant Green onto modified peat-resin particle is examined. The adsorption isotherm showed that the adsorption of basic dyes on modified peat-resin particle deviated from the Langmuir and Freundlich equations. The pseudo-first order, pseudo-second order and intraparticle diffusion models were used to fit the experimental data. By comparing the standard deviation, it was found that the intraparticle diffusion model could be used to well describe the adsorption of two basic dyes on modified peat-resin particle. According to the change of intraparticle diffusion parameter, the adsorption processes could be divided into different stages. The kinetics experiment also indicated that initial dye concentrations, particle dose and particle size could affect the adsorption processes of basic dyes. (C) 2002 Elsevier Science Ltd. All rights reserved.

Keywords: Modified Peat-Resin Particle, Basic Dyes, Adsorption Isotherm, Adsorption Kinetics, Kinetic Models, Acid Dye, Natural Adsorbents, Waste-Water, Metal-Ions, Sorption, Removal, Diffusion, Moss

Abollino, O., Aceto, M., Malandrino, M., Sarzanini, C. and Mentasti, E. (2003), Adsorption of heavy metals on Na-montmorillonite: Effect of pH and organic substances. Water Research, 37 (7), 1619-1627.

Full Text: W\Wat Res37, 1619.pdf

Abstract: Clays (especially montmorillonite and bentonite) are widely used as barriers in landfills to prevent contamination of subsoil and groundwater by leachates containing heavy metals. For this reason it is important to study the adsorption of metals by these clays. The sorption of seven metals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) on Na-montmorillonite was studied as a function of pH and in the presence of ligands, forming complexes of different stabilities with the metals of interest. The continuous column method was used as it better simulates natural conditions. The total capacity of Na-montmorillonite towards these metals was determined. The pH variations influence to a higher extent the concentrations of Cu, Pb and Cd in the effluent. Moreover the results suggest that complex formation hinders the sorption of the metals on the clay, with an increasing influence in the order: Mn less than or equal to Pb less than or equal to Cd less than or equal to Zn < Ni < Cu < Cr. The evaluation of the total capacity of Na-montmorillonite shows that this clay is a good sorbent towards all examined metals. (C) 2002 Elsevier Science Ltd. All rights reserved.

Keywords: Na-Montmorillonite, Heavy Metals, Adsorption, Metal Complexes, Breakthrough, Sorbents, Surface

Notes: highly cited

? Ternes, T.A., Stuber, J., Herrmann, N., McDowell, D., Ried, A., Kampmann, M. and Teiser, B. (2003), Ozonation: A tool for removal of pharmaceuticals, contrast media and musk fragrances from wastewater? Water Research,