Personal Research Database

Full Text: S\Sep Sci Tec35, 689.pdf

Abstract: Biosorption of heavy metals can be an effective process for the removal and recovery of heavy metal ions from aqueous solutions. The biomass of marine macroalgae has been reported to have high uptake capacities for a number of heavy metal ions. In this paper the adsorption properties of a pretreated biomass of macroalga Durvillaea potatorum for Ni²⁺ were investigated. Adsorption isotherms and kinetics were obtained from batch adsorption experiments. The adsorption capacities were pH dependent and a maximum adsorption capacity was obtained to be 1.13 mmol/g at a pH of about 6. A modified Langmuir model was proposed for the correlation of pH-dependent isotherms. The adsorption process was fast, 90% of adsorption occurred within 25 minutes and equilibrium was reached at around 1 hour. Light metal ions at a concentration of 10 mM did not affect Ni²⁺ adsorption significantly. Fixed-bed breakthrough curves for Ni²⁺ removal were also obtained. This study demonstrated that the pretreated biomass of D. potatorum can be used as an effective biosorbent for the treatment of Ni²⁺-containing wastewater streams.

Keywords: Heavy-Metal Biosorption, Cadmium Adsorption, Removal, Sorption, Water, Algae, Ions, pH, Biosorption of Heavy Metals, Marine Macroalgae, Durvillaea potatorum, Wastewater Treatment

Guibal, E., Milot, C. and Roussy, J. (2000), Influence of hydrolysis mechanisms on molybdate sorption isotherms using chitosan. Separation Science and Technology, 35 (7), 1021-1038.

Full Text: S\Sep Sci Tec35, 1021.pdf

Abstract: Molybdate sorption using chitosan sorbents has proved to be strictly controlled by the pH of the solution. Sorption isotherms exhibit a sigmoid trend, which has been correlated to the appearance of polynuclear hydrolyzed species, the most favorable species for sorption on chitosan. Sorption capacity exceeds 7 mmol.g^-1, which corresponds to a molar ratio between Mo and the amine group significantly higher than 1. The formation of complexes in a pendant fashion and/or the ion-exchange mechanism of polynuclear metal ions are suspected to occur between polynuclear molybdate species and protonated amine groups, though several amine groups can interact with the same polynuclear molybdate group.

Keywords: Chitosan, Molybdate, Hydrolysis, Sorption, Isotherms, pH

? Chern, J.M. and Chang, F.C. (2000), Study of nonlinear wave propagation theory. III. removing heavy metals from wastewater by ion-exchange process. Separation Science and Technology, 35 (8), 1099-1116.

Full Text: 2000\Sep Sci Tec35, 1099.pdf

Abstract: The nonlinear wave propagation theory has been applied to predict the breakthrough and regeneration curves of ion-exchange columns for heavy metal removal. Batch experimental tests using IRC-718 cationic resin were conducted to obtain the ion-exchange equilibria of H/Cu and H/Ni systems, and column tests were conducted to obtain the breakthrough and regeneration curves under various operating conditions. The batch experimental results show that the affinity sequence is Cu > H > Ni. The column experimental results show that IRC-718 In H-form is effective for removing copper from synthetic wastewater but not effective for nickel removal. For a copper-rich feed solution, the ion-exchange wave is a self-sharpening wave and its regeneration wave is a nonsharpening one. For a nickel-rich feed solution, the ion-exchange wave is a nonsharpening wave and its regeneration wave is a self-sharpening one. For a copper/nickel mixture feed, nickel gradually appears in the effluent, and a plateau of concentration higher than the feed one is identified. Simple equations based on the nonlinear wave propagation theory have been developed to predict the breakthrough and regeneration curves, and the predicted results are quite comparable with the experimental data.

Keywords: Breakthrough, Chromatography, Dye Adsorption, Dynamics, Heavy Metal, Heavy Metals, Interference, Ion Exchange, Multicomponent, Regeneration, Removal, Wastewater, Wave Propagation

Walker, G.M. and Weatherley, L.R. (2000), Textile wastewater treatment using granular activated carbon adsorption in fixed beds. Separation Science and Technology, 35 (9), 1329-1341.

Full Text: S\Sep Sci Tec35, 1329.pdf

Abstract: This work involved the treatment of industrial wastewater from a nylon carpet printing plant which currently receives no treatment and is discharged to sea. As nylon is particularly difficult to dye, acid dyes are required for successful coloration and cause major problems with the plant’s effluent disposal in terms of color removal. Granular activated carbon Filtrasorb 400 was used to treat a ternary solution of acid dyes and the process plant effluent containing the dyes in a fixed-bed column system. Experimental data were correlated using the bed depth service time (BDST) model to previously published work by the authors for single dye adsorption. The results were expressed in terms of the BDST adsorption capacity, in milligrams of adsorbate per gram of adsorbent, and indicated that there was a 12-25% decrease iri adsorption capacity in the ternary system compared to the single component system, This reduction has been attributed to competitive adsorption occurring in the ternary component system. Dye adsorption from the process plant effluent showed an approximate 65% decrease in adsorption capacity compared to the ternary solution system. This has been attributed to interference caused by the other colorless textile effluent pollutants found in the process wastewater. A chemical oxygen demand analysis on these components indicated that the dyes accounted for only 14% of the total oxygen demand.

Keywords: Activated Carbon, Adsorption, Bed Depth Service Time, Bed Depth Service Time Model, Column, Copper, Dye, Dye Adsorption, Dyes, Dyestuffs, Fixed Bed, Fixed Bed Column, Fixed-Bed, Fixed-Bed Column, Granular Activated Carbon, Model, Removal, Systems, Textile Process Effluent, Wastewater, Wastewater Treatment, Water

? Suen, S.Y., Chiu, H.C. and Tsai, Y.D. (2000), Polysaccharide-modified poly(ether sulfone) hollow fibers as solid supports for affinity adsorption: Equilibrium adsorption study. Separation Science and Technology, 35 (9), 1343-1362.

Full Text: 2000\Sep Sci Tec35, 1343.pdf

Abstract: Poly(ether sulfone) hollow fibers modified with various polysaccharides were used to immobilize Cibacron Blue 3GA for affinity adsorption. Characterization of modified hollow fibers with respect to their activation using ethylene glycol diglycidyl ether, conjugation with polysaccharides, and immobilization with Cibacron Blue 3GA indicates that the surface modification was successfully achieved. This work also studied the adsorption behavior of lysozyme onto immobilized Cibacron Blue 3GA using the polysaccharide-modified fibers as solid supports. The optimal adsorption capacity was observed from the hollow fibers conjugated with hydroxyethyl cellulose or dextran derivative and with high density of immobilized Cibacron Blue 3GA. Moreover, the effect of temperature on lysozyme adsorption was investigated. The results show that the lysozyme-ligand binding on the polysaccharide-modified hollow fibers tends to be endothermic.

Keywords: Adsorption, Adsorption Capacity, Amino-Acids, Behavior, Breakthrough, Capacity, Cellulose, Density, Ethylene, Fibers, Immobilization, Immunoaffinity Chromatography, Immunoglobulin-G, Lysozyme, Membrane, Modification, Modified, Performance, Polysaccharides, Proteins, Purification, Separation, Sulfone, Supports, Surface, Surface Modification, Temperature

Tsai, W.T., Chang, C.Y., Ho, C.Y. and Chen, L.Y. (2000), Adsorption properties and breakthrough model of 1,1-dichforo-1-fluoroethane on granular activated carbon and activated carbon fiber. Separation Science and Technology, 35 (10), 1635-1650.

Full Text: S\Sep Sci Tec35, 1635.pdf

Abstract: 1,1-dichloro-1-fluoroethane (HCFC-141b) is current recognized as an excellent substitute for chlorofluorocarbons (e.g., CFC-11 and CFC-113). In the present work fixed-bed adsorption studies were performed on the use of granular activated carbon (GAC) and activated carbon fiber (ACF) for the recovery of HCFC-141b vapor from air. Adsorption equilibria were obtained at 283, 293, 303, and 313 K. Three classic models (Langmuir, Freundlich, and Dubinin-Radushkevich) were applied and their parameter constants were determined by regression analysis. It was found that these isotherms were fitted well by the measured adsorption data, and the determined parameters of isotherm equations were consistent with the physical properties (e.g., specific surface areas and pore volumes) of these carbon adsorbents. It is clear that the performance of adsorbent ACF is significantly better than that of adsorbent GAC in terms of the adsorption capacity and the adsorption rate. A simple two-parameter model, originally introduced by Yoon and Nelson, was adopted to describe the entire breakthrough curves regarding the adsorption of HCFC-141b vapor through carbon columns at 283 K. The results indicate that the calculated breakthrough curves agree well with the corresponding experimental data.

Keywords: HCFC-141b, Granular Activated Carbon, Activated Carbon Fiber, Adsorption

Gupta, V.K., Mohan, D., Sharma, S. and Sharma, M. (2000), Removal of basic dyes (rhodamine B and Methylene blue) from aqueous solutions using bagasse fly ash. Separation Science and Technology, 35 (13), 2097-2113.

Full Text: S\Sep Sci Tec35, 2097.pdf

Abstract: Bagasse fly ash, a waste generated in sugar industries in India, has been converted into an inexpensive adsorbent material and utilized for the removal of two basic dyes, rhodamine B and Methylene blue. Results include the effect of pH, adsorbent dose, dye concentration, and presence of surfactant on the removal of rhodamine B and Methylene blue. The adsorption data have been correlated with both Langmuir and Freundlich adsorption models. Thermodynamic parameters obtained indicate the feasibility of the process, and kinetic studies provided the necessary mechanistic information of the removal process.

Keywords: Adsorption, Basic Dyes, Bagasse Fly Ash, Wastewater, Removal, Solid Waste Utilization, Waste-Water, Color Removal, Activated Carbon, Equilibrium Uptake, Sorption Dynamics, Column Operations, Sugar-Industry, Fixed-Bed, Adsorption, Slag

Al-Degs, Y.S., Tutunju, M.F. and Shawabkeh, R.A. (2000), The feasibility of using diatomite and Mn-diatomite for remediation of Pb²⁺, Cu²⁺, and Cd²⁺ from water. Separation Science and Technology, 35 (14), 2299-2310.

Full Text: S\Sep Sci Tec35, 2299.pdf

Abstract: Diatomite and manganese-oxide-modified-diatomite (Mn-diatomite) were tested as adsorbents for Pb²⁺, Cu²⁺, and Cd²⁺ removal from water. Impregnating the surface of diatomite with 0.38 g of manganese oxide per gram diatomite shows an increase of 2.4-fold in the surface area of the modified diatomite. The adsorption capacities were 99, 51, and 26 mg/g Mn-diatomite for Pb²⁺, Cu²⁺, and Cd²⁺, respectively, obtained at solution pH 4, while values of 24, 21, and 16 mg/g diatomite were obtained at the same conditions and for the same metals. The obtained adsorption kinetics experimental data display that 95% of the original Pb²⁺ concentrated was adsorbed by Mn-diatomite within 10 min, while kinetic data for diatomite showed a lower rate for Pb²⁺ uptake. The filtration quality of diatomite was significantly enhanced with the surface modification by manganese oxide.

Keywords: Adsorption, Metal Ions, Diatomite, Adsorption, Sorption

Biškup, B. and Subotić, B. (2000), Removal of heavy-metal ions from solutions by means of zeolites. II. Thermodynamics of the exchange processes between zinc and lead ions from solutions and sodium ions from zeolite A. Separation Science and Technology, 35 (14), 2311-2326.

Full Text: S\Sep Sci Tec35, 2311.pdf

Abstract: Relationships between the corrected selectivity coefficient, K-C(Me) (Me = Zn, Pb), and fraction of the exchanged Me²⁺ ions in zeolite A, f(Me, Z), were determined from the corresponding exchange isotherms. The exchange isotherms were obtained by measuring the equilibrium concentrations of sodium and Me²⁺ ions in both the solid and the liquid phase at constant total-ion concentrations and different temperatures in the range from 20 degreesC to 60 degreesC. Thermodynamic equilibrium constants, K-a(Me), calculated from the corresponding Kielland’s plots (lnK(C)(Me) vs. f(Me, Z) plots) were used for the calculation of the appropriate values of standard free energy, G° (Me), standard enthalpy, H° (Me), and standard entropy, S° (Me).

Keywords: Zeolite A, Ion Exchange, Sodium Ions, Zinc Ions, Lead Ions, Exchange Equilibrium, Thermodynamic Data, Waste-Water, Natural Zeolites, Cadmium, Calcium, Ni, 4A

? Kim, Y.H. (2000), Adsorption characteristics of cobalt on ZrO₂ and Al₂O₃ adsorbents in high-temperature water. Separation Science and Technology, 35 (14), 2327-2341.

Full Text: 2000\Sep Sci Tec35, 2327.pdf

Abstract: To evaluate adsorbents for the removal of soluble corrosion products, mainly Co-60 under PWR reactor coolant conditions, ZrO₂ and Al₂O₃ were prepared by the sol-gel method and hydrolysis of metal alkoxide, respectively. Their structures were studied by x-ray diffractometer and TG-DTA. The Co²⁺ adsorption on ZrO₂ and Al₂O₃ in high-temperature water were investigated in a stirred hatch autoclave. The effect of calcination temperature on Co²⁺ adsorption capacity of ZrO₂ and Al₂O₃, the effect of pH on Co²⁺ adsorption capacity of Al₂O₃, the effect of adsorption temperature on adsorption capacity and Co²⁺ adsorption isotherms were studied. The prepared ZrO₂ and Al₂O₃ adsorbents were found to be stable with tetragonal, monoclinic structures and theta, delta, and alpha phase structures, respectively. The enthalpy changes (DeltaH degrees) due to the adsorption of Co²⁺ on ZrO₂ and Al₂O₃ were 12.8 and 16.1 kJ/gmol, which suggest that the adsorption is an irreversible endothermic reaction in the experiment temperature (150 similar to 250 degreesC). The Co²⁺ adsorption capacities of ZrO₂ and Al₂O₃ at 250 degreesC were 0.16 and 0.18 meq Co²⁺/g adsorbent, respectively. The thermodynamic function of adsorption of DeltaH, DeltaS, DeltaG, and equilibrium constant K-d were calculated. The process of adsorption was established to be endothermic, and chemisorption was stabilized through thermodynamic functions.

Keywords: Adsorbent, Adsorbents, Adsorption, Adsorption Capacities, Adsorption Capacity, Adsorption Isotherms, Calcination, Capacity, Changes, Characteristics, Chemisorption, Co(II), Co²⁺, Cobalt, Corrosion, Endothermic, Enthalpy, Equilibrium, Experiment, Function, Functions, Hydrolysis, Isotherms, Metal, pH, Removal, Sol-Gel, Temperature, Thermodynamic, Thermodynamic Functions, Titanium-Oxide, Water

Mondal, K. and Lalvani, S.B. (2000), Modeling of mass transfer controlled adsorption rate based on the Langmuir adsorption isotherm. Separation Science and Technology, 35 (16), 2583-2599.

Full Text: S\Sep Sci Tec35, 2583.pdf

Abstract: Adsorption techniques are extensively used in bulk separations, purifications, and physiochemical parameter determinations. Generally, the adsorption models are described for equilibrium conditions. This study investigates the development of a mathematical model which describes the rate of adsorption under the conditions when the dynamic mass transfer is the controlling step. The underlying assumption is that the equilibrium isotherms can be used to describe the adsorption phenomena. A mathematical model for the external mass transfer controlled adsorption rate based on the Langmuir adsorption isotherm was developed and validated using data reported in literature using different adsorbents and adsorbates. In addition, using Freundlich adsorption isotherm, mathematical models for zero, one-half, and first-order were obtained. The various relevant parameters, namely the adsorption capacity, the adsorption energy, and the mass transfer coefficients were evaluated and the extension of the model to energetically heterogeneous surfaces is discussed. In addition, the results obtained from the Langmuir isotherm-based model were compared against the results derived from the mass transfer controlled rate equation based on the Freundlich isotherm.

Keywords: Langmuir, Adsorption, Kinetics, Mass Transfer, Modeling, Ctivated Carbon, Fly-Ash, Kinetics, Surfaces

Sağ, Y., Kaya, A. and Kutsal, T. (2000), Biosorption of lead(II), nickel(II), and copper(II) on Rhizopus arrhizus from binary and ternary metal mixtures. Separation Science and Technology, 35 (16), 2601-2617.

Full Text: S\Sep Sci Tec35, 2601.pdf

Abstract: The biosorption of three divalent metal ions [Pb(II), Ni(II), and Cu(II)] frequently encountered together in industrial waste waters and in binary and ternary systems was studied using Rhizopus arrhizus, a filamentous fungus, in batch stirred reactors. The multimetal biosorption data were evaluated in terms of equilibrium isotherms and adsorption yields. The single-metal equilibrium data were analyzed using the Freundlich adsorption model. The individual Freundlich adsorption constants were determined and used to compare biosorptive capacity of the microorganism for different metal ions. The effects of various combinations of the metal ions on the biosorption capacity of R. arrhizus are discussed and the actions of the synergistic or antagonistic metal ion combinations were determined. For the two-metal adsorption equilibrium, competitive adsorption isotherms have been also developed. The six-parameter empirical Freundlich model, restricted to bicomponent systems, was used successfully to characterize simultaneous biosorption of Pb(II), Ni(II), and Cu(II) ions by R. arrhizus from two-metal systems. The biosorption capacity of Pb(II) in the two binary and one ternary systems, in agreement with the single-metal data, was greater than that of the Ni(II) and Cu(II) ions. The relative capacities were Pb(II) > Ni(II) > Cu(II) at pH 5.0 in single, binary, and ternary systems.

Keywords: Waste Water Treatment, Heavy Metal Ion, Biosorption, Rhizopus arrhizus, Multimetal Mixtures, Empirical Freundlich Adsorption Model, Heavy-Metal, Aqueous-Solutions, Fungal Biomass, Adsorption Equilibria, Penicillium Biomass, Activated Carbon, Removal, Microalgae, Isotherms, Ramigera

Al-Degs, Y., Khraisheh, M.A.M., Allen, S.J. and Ahmad, M.N.A. (2001), Sorption behavior of cationic and anionic dyes from aqueous solution on different types of activated carbons. Separation Science and Technology, 36 (1), 91-102.

Full Text: S\Sep Sci Tec36, 91.pdf

Abstract: The effect of dye molecular charges on their adsorption from solution was investigated by using different types of activated carbon adsorbents. Two types of model systems were used representing cationic and anionic dyes. Screening investigations using single point tests were used throughout the study. Cationic dyes, of which Methylene Blue is an example, showed a higher adsorption tendency towards activated carbon over anionic dyes represented by an ate-type reactive compound. of the number of activated carbons tested, only one of the adsorbents showed an exception to this behavior, and a good relation was observed between Methylene Blue capacity and activated carbon performance. The high capacity of cationic dyes in comparison to anionic dyes was also evident in the results obtained by a preliminary kinetic study carried out on the selected systems. Surface net charge of activated carbon and the nature of attractions between the molecules were suggested to be one of the reasons attributed for this behavior.

Keywords: Adsorption, Activated Carbons, Cationic and Anionic Dyes, Spent Bleaching Earth, Reactive Dyes, Organic-Dyes, Adsorption, Removal, Clay

Suzuki, T.M., Tanco, M.L., Tanaka, D.A.P., Matsunaga, H. and Yokoyama, T. (2001), Adsorption characteristics and removal of oxo-anions of arsenic and selenium on the porous polymers loaded with monoclinic hydrous zirconium oxide. Separation Science and Technology, 36 (1), 103-111.

Full Text: S\Sep Sci Tec36, 103.pdf

Abstract: Adsorption properties for oxoanions of Se(IV), Se(VI), As(III), As(V), and methyl derivatives of As(V) have been examined by the porous polymer beads loaded with monoclinic hydrous zirconium oxide (Zr-resin). The retention of these ions on the Zr-resin has been analyzed using Langmuir model of adsorption. The equilibrium constants and the capacities for above ions have been determined. The equilibrium constants for monomethyl arsinic acid and dimethyl arsinic acid are similar to that of As(V) but the adsorption capacity depends on the number of methyl groups. As(V) and Se(IV) are effectively retained on the Zr-resin from an aqueous solution of acidic to neutral pH region, whereas As(III) is removed from neutral to alkaline solution. The column system packed with the present Zr-resin can quantitatively remove low levels of As(V) and Se(IV) from aqueous solution.

Keywords: Separation, Oxoanions, Selenium, Arsenic, Zirconium Oxide, Water Treatment, Water

Koch, H.F. and Roundhill, D.M. (2001), Removal of mercury(II) nitrate and other heavy metal ions from aqueous solution by a thiomethylated lignin material. Separation Science and Technology, 36 (1), 137-143.

Full Text: S\Sep Sci Tec36, 137.pdf

Abstract: Lignin has been derivatized with methylthioether functional groups in order to reduce its solubility in water. This new chemically modified lignin material has been used as a solid adsorbent for mercury(II) nitrate from aqueous solution. This adsorbent strongly adsorbs nitrate salts of lead(II), cadmium(II), and copper(II) from their solutions in water. The nitrate salts of the trivalent metals chromium(III) and iron(III) are also strongly adsorbed. Sodium(I) nitrate is not adsorbed from aqueous solution and calcium(II) nitrate only moderately so. These metal extraction data are compared with those obtained with methylthioether functionalized calix[4]arenes, which show a similar preference for mercury(II), but a lower preference for lead(II), cadmium(II), and iron(III).

Keywords: Lignin, Mercury, Methylthioether

Hall, C., Wales, D.S. and Keane, M.A. (2001), Copper removal from aquous systems: Biosorption by Pseudomonas syringae. Separation Science and Technology, 36 (2), 223-240.

Full Text: S\Sep Sci Tec36, 223.pdf

Abstract: The potential of two strains of Pseudomonas syringae (Blue and Brown) to remove copper from aqueous solutions has been investigated and assessed against the synthetic Linde LZ-52Y aluminosilicate zeolite. The two bacterial strains were tolerant to copper and were able to grow in media doped with concentrations of up to 1000 ppm. The biosorptive capacity and the mechanism of copper uptake were investigated using ‘active’ and ‘inactive’ species grown in nutrient-rich and complex media. The degree of copper removal by ion exchange with the Y zeolite is reported and compared with that achieved when using the biosorbents under the same treatment conditions. The bacteria were harvested, freeze-dried, and used to adsorb copper under starved and glucose activated conditions. The need to distinguish between ‘bio-uptake’ and the action of complexing agents that may be present are highlighted. The experimental data are fitted to standard Freundlich, BET, and Langmuir adsorption models where the latter yielded both meaningful theoretical maximum adsorption capacities and adsorption affinity coefficients. These values are discussed in terms of the sorbate/sorbent interactions, which are shown to involve a passive mechanism where the majority of the copper attaches to the outer cell wall.

Keywords: Adsorption, Copper Uptake, Langmuir Model, Pseudomonas Syringae, Zeolite Y, Biosorption Mechanism, Saccharomyces-Cerevisiae, Metal-Ions, Organic-Ligands, Waste-Water, PV Tomato, Adsorption, Resistance, Cells, Accumulation, Langmuir

Notes: highly cited

Ho, Y.S., Ng, J.C.Y. and McKay, G. (2001), Removal of lead(II) from effluents by sorption on peat using second-order kinetics. Separation Science and Technology,