Personal Research Database

Full Text: 1998\Sep Sci Tec33, 1043.pdf

Abstract: Crab shell particles (Protunus trituberculatus) and activated carbon (Norit 0,8 SUPRA) were used as packing materials in a fixed-bed column. When 1 g crab shell was added in a column packed with 10 g activated carbon, breakthrough occurred at 1500 bed volumes as compared to 380 bed volumes for 10 g activated carbon only. The addition of crab shell particles into an activated carbon column resulted in an increased uptake of lead. The dramatic improvement might be attributed to an increase in CO₃^2- and OH^- available for binding lead. From the results of SEM, XRD, and FT-IR analyses, the major mechanism of lead removal was based on dissolution of CaCO₃ in the crab shell followed by precipitation of Pb-3(CO₃)₂(OH)_2(S) on the surface of activated carbon. The lead uptake increased twofold when the influent lead concentration was increased from 10 to 50 mg, L.

Keywords: Activated Carbon, Adsorption, Aqueous-Solution, Breakthrough, Column, Copper, Crab Shell, Fixed Bed, Fixed Bed Column, Fixed-Bed, Fixed-Bed Column, Heavy-Metals, Lead, Precipitation, Removal, Waste Streams

Al-Asheh, S. and Duvnjak, Z. (1998), Binary metalsorption by pine bark: Study of equilibria and mechanisms. Separation Science and Technology, 33 (9), 1303-1329.

Full Text: 1998\Sep Sci Tec33, 1303.pdf

Abstract: Pine bark was able to sorb cadmium, copper, and nickel ions from aqueous solutions. Binary equilibrium data from the combination of these metals were collected in this work using this sorbent. These data were modeled using three types of binary component equilibrium isotherms, all of which resulted in good fitting of the experimental data, with the Langmuir-Freundlich model resulting in their best representation. In general, the capacity of bark for each metal in the binary system was lower than in the single metalsystems, The study also examined the mechanisms of metal biosorption by bark. Scanning electron microscopy (SEM) and energy-dispersive xray (EDX) microanalyses revealed that metal ions were sorbed mainly at the cell wall of the bark and only a small amount of ions diffused into the cytoplasm. Both the EDX analysis and the atomic absorption spectrophotometry (AAS) measurements showed that ion exchange was an important mechanism in this sorption process. Electron spin resonance (ESR) tests demonstrated that free radicals from the sorbent also have a significant role in the sorption processes.

Keywords: Adsorbents, Adsorption, Agricultural By-Products, Aqueous-Solutions, Bark, Biosorption, Biosorption Equilibria, Cadmium, Combination, Copper, Edx, Equilibrium Isotherms, Heavy-Metals, Ion Exchange, Ion-Exchange, Metal, Metal Ions, Metal Sorption, Metals, Nickel, Pine Bark, Protons, Removal, Rhizopus-arrhizus Biomass, SEM, Sorbent, Sorption

Gupta, V.K., Mohan, D. and Sharma, S. (1998), Removal of lead from wastewater using bagasse fly ash: A sugar industry waste material. Separation Science and Technology, 33 (9), 1331-1343.

Full Text: 1998\Sep Sci Tec33, 1331.pdf

Abstract: Bagasse fly ash, a waste generated in sugar industries in India, has been converted into a low cost adsorbent and has been used for the removal of lead from aqueous solutions in the 4.8010^-4 to 4.8310^-3 M concentration range, Maximum removal takes place at pH 3.0 using 10 g.L^-1 of the adsorbent of particle size 150-200 mesh. The effect of the presence of other metal ions, temperature, and contact time has also been studied. Sorption data have been correlated with both Langmuir and Freundlich adsorption models. The adsorbent has been satisfactorily used for the removal of Pb²⁺ from the effluent of a metal-finishing plant.

Keywords: Metal-Ions, Adsorption, Water, Equilibrium, Sorption, Lead, Wastewater Treatment, Low Cost Adsorbent, Adsorption, Bagasse Fly Ash, Metal Ions, Solid Waste Utilization

? Kwon, S.C., Song, D.I. and Jeon, Y.W. (1998), Adsorption of phenol and nitrophenol isomers onto montmorillonite modified with hexadecyltrimethylammonium cation. Separation Science and Technology, 33 (13), 1981-1998.

Full Text: 1998\Sep Sci Tec33, 1981.pdf

Abstract: Single- and two-component competitive adsorptions were carried out in a batch adsorber to investigate the adsorption behavior of phenol and 2-, 3-, and 4-nitrophenols in aqueous solution at 25C onto hexadecyltrimethylammonium (HDTMA)-treated montmorillonite. HDTMA cation was exchanged for metal cations on the montmorillonite to prepare HDTMA-montmorillonite, changing its surface property from hydrophilic to organophilic. Effective solid diffusivity of HDTMA cation in the montmorillonite particle was estimated to be about 310^-12 cm²/s by fitting the film-solid diffusion model to a set of HDTMA adsorption kinetic data onto montmorillonite. Adsorption affinity on HDTMA-montmorillonite was found to be in the order 3-nitrophenol approximate to 4-nitrophenol > 2-nitrophenol > phenol. The Langmuir and the Redlich-Peterson (RP) adsorption models were used to analyze the single component adsorption equilibria. The ideal adsorbed solution theory (IAST) and the Langmuir competitive model (LCM) were used to predict the multicomponent competitive adsorption equilibria. These models yielded favorable representations of both individual and competitive adsorption behaviors.

Keywords: Adsorption, Adsorption Kinetic, Behavior, Diffusion, Hdtma, Hexadecyltrimethylammonium, Hydrophilic, Ideal, Kinetic, Langmuir, Model, Models, Modified, Montmorillonite, Organic Phenols, Particle, Phenol, Predict, Smectite, Sorption, Surface, Water

? Song, H.K. and Lee, K.H. (1998), Adsorption of carbon dioxide on chemically modified carbon adsorbents. Separation Science and Technology, 33 (13), 2039-2057.

Full Text: 1998\Sep Sci Tec33, 2039.pdf

Abstract: Carbon adsorbents were chemically modified to have base sites on their surfaces, and the adsorption characteristics of carbon dioxide on them were investigated. Three kinds of carbon materials were used as support materials: two activated carbons and a carbon black. Base sites were introduced by impregnating the support materials with calcium acetate solution, followed by calcination at 700°C for 2 hours in an inert gas flow. Chemical modification reduced the surface areas of adsorbents due to the blocking of micropores. Irreversible adsorption of carbon dioxide occurs up to 300°C due to chemisorption. However, reversible adsorption was possible by pretreating adsorbents with carbon dioxide. Strong interaction between carbon dioxide and base sites enhanced adsorption of carbon dioxide at higher temperatures up to 250°C.

Keywords: Acetate, Adsorbents, Adsorption, Calcium, Carbon, Carbon Adsorbents, Carbon Dioxide, Chemisorption, Flow, Gas, Interaction, Materials, Modification, Modified, Separation, Sites, Surface, Surfaces

Khalid, N., Ahmad, S., Kiani, S.N. and Ahmed, J. (1998), Removal of lead from aqueous solutions using rice husk. Separation Science and Technology, 33 (15), 2349-2362.

Full Text: 1998\Sep Sci Tec33, 2349.pdf

Abstract: Rice husk, an agricultural waste, was studied as a potential scavenger of lead from various aqueous solutions. Physicochemical parameters such as selection of appropriate electrolyte, shaking time, and the concentrations of adsorbent and adsorbate were studied to optimize the conditions to be utilized on a commercial scale for the decontamination of effluents using a batch technique. Maximum adsorption was observed with 0.01 mol.dm^-3 acid solutions (HNO₃, HCl, H₂SO₄ and HClO₄) using 1000 mg of adsorbent for a 4.8210^-5 mol.dm^-3 lead concentration in less than 10 minutes equilibration time. Studies show that the adsorption decreases with an increase in the concentrations of all the acids. The adsorption data follows the Freundlich isotherm over the 9.6510^-5 to 4.8310^-3 mol.dm^-3 range of lead concentration. The characteristic Freundlich constants, i.e., 1/n = 0.93±0.04 and A = 19.86±0.82 m.mol.g^-1, have been computed for the sorption system. Thermodynamic parameters, i.e., Delta G degrees, Delta S degrees, and Delta H degrees, have also been calculated for the system.

Keywords: Heavy-Metal Ions, Atomic-Absorption Spectrometry, Trace-Metals, Sea-Water, Preconcentration, Adsorption, Binding, Seawater, Cadmium, Carbon

Kabay, N., Demircioglu, M., Yayli, S., Yuksel, M. and Saglam, M., Levison, P.R. (1999), Removal of metal ions from aqueous solution by cellulose ion exchangers. Separation Science and Technology, 34 (1), 41-51.

Full Text: S\Sep Sci Tec34, 41.pdf

Abstract: The sorption of metal ions [Cd(II), Cu(II), Co(II), Pb(II), Zn(II), Cr(III), V(IV), V(V) from aqueous solution by Whatman cellulose ion exchangers was investigated as a function of pH. Whatman P-ll (ammonium cellulose phosphate) exhibited better performance than a fibrous anion exchanger (Whatman Cellect-Ion Exchanger DT-1) with respect to their sorption capacities for Cd(II), Cu(II), Co(II), Pb(II), Zn(II), and Cr(III). The Cellect-Ion anion exchanger (DT-1) had a higher sorption for V(IV) and V(V). The ionic form of cellulose phosphate (P-11) influenced their metal sorption capacities.

Keywords: Selective Separation, Preconcentration, Lead

Namasivayam, C. and Senthilkumar, S. (1999), Adsorption of copper(II) by ‘waste’ Fe(III)/Cr(III) hydroxide from aqueous solution and radiator manufacturing industry wastewater. Separation Science and Technology, 34 (2), 201-217.

Full Text: S\Sep Sci Tec34, 201.pdf

Abstract: ‘Waste’ Fe(III)/Cr(III) hydroxide has been used as an adsorbent for the effective removal of copper from aqueous solution. The parameters studied include agitation time, Cu(II) concentration, adsorbent dose, temperature, and pH. The percent adsorption of Cu(II) increased with a decrease in the concentration of Cu(II) and an increase in temperature. Quantitative removal of Cu(II) by 50 mg/50 mt adsorbent was observed at pH 5.0 for a Cu(II) concentration of 40 mg/L. The equilibrium data fit well with the Langmuir isotherm. The adsorption capacity (Q₀) calculated from the Langmuir isotherm was 92.59 mg/g at an initial pH of 5.0 at 32°C. Desorption of Cu(II) from a Cu(II)-loaded adsorbent was 55.4% at pH 3.0. Application of the adsorbent for the removal of Cu(II) was successfully demonstrated using radiator manufacturing industry wastewater.

Keywords: Removal, Water, Equilibrium, Adsorbents, Carbon, Cd(II)

Hasany, S.M., Saeed, M.M. and Ahmed, M. (1999), Retention of Hg(II) by solid mercury sulfide from acidic solution. Separation Science and Technology, 34 (3), 487-499.

Full Text: S\Sep Sci Tec34, 487.pdf

Abstract: Mercury sulfide was prepared and characterized by measuring average pore size and surface area. The sorption of mercury onto mercury sulfide was investigated in detail with respect to sorptive medium, agitation time, sorbent and sorbate concentration, and temperature. The maximum sorption of mercury (>99.8) was achieved from 10^-3 M hydrochloric acid solution using 50 mg mercury sulfide for 10 minutes. The sorption data of mercury followed the Langmuir isotherm over the entire concentration of mercury investigated whereas the Freundlich and Dubinin–Radushkevich isotherms were obeyed only up to low and moderate concentrations. Useful parameters like sorption capacity and energy have been evaluated using these isotherms. The variation of the equilibrium constant with temperature has the results ΔH=23.8±3.2 kJ.mol^-1, ΔS = 130±10 J.mol^-1, and ΔG = -13.5±0.4 kJ.mol^-1 at 298 K. Among the ions tested, tartrate, fluoride, and citrate increase the sorption whereas Cu(II), Ba(II), Zn(II), Ni(II), Fe(II), and Cr(III) reduce the sorption significantly. Except for Y(III) (~91%), all the metal ions showed a lower affinity toward HgS, especially trivalent Ho, Fe, Sc, Tm, Ga, Dy, As, and Pr which showed sorption >1 and >10%. The mercury sulfide column can be used to separate Hg(II) from these trivalent metal ions.

Aksu, Z., Açikel, Ü. and Kutsal, T. (1999), Investigation of simultaneous biosorption of copper(II) and chromium(VI) on dried Chlorella vulgaris from binary metal mixtures: Application of multicomponet adsorption isotherms. Separation Science and Technology, 34 (3), 501-524.

Full Text: S\Sep Sci Tec34, 501.pdf

Abstract: Although the biosorption of single metal ions to various kinds of microorganisms has been extensively studied and the adsorption isotherms have been developed for only the single metal ion situation, very little attention has been given to the bioremoval and expression of adsorption isotherms of multimetal ions systems. In this study the simultaneous biosorption of copper(II) and chromium(VI) to Chlorella vulgaris from a binary metal mixture was studied and compared with the single metal ion situation in a batch stirred system. The effects of pH and single-and dual-metal ion concentrations on the equilibrium uptakes were investigated. In previous studies the optimum biosorption pH had been determined as 4.0 for copper(II) and as 2.0 for chromium(VI). Multimetal ion biosorption studies were performed at these two pH values. It was observed that the equilibrium uptakes of copper(II) or chromium(VI) ions were changed due to the biosorption pH and the presence of other metal ions. Adsorption isotherms were developed for both single-and dual-metal ion systems at these two pH values, and expressed by the mono-and multicomponent Langmuir and Freundlich adsorption models. Model parameters were estimated by nonlinear regression. It was seen that the adsorption equilibrium data fitted very well to the competitive Freundlich model in the concentration ranges studied.

Keywords: Simultaneous Biosorption, Binary Mixture of Copper(II) and Chromium(VI), Chlorella vulgaris, Mono-and Multicomponent Adsorption Isotherms, Heavy-Metals, Waste-Water, C. Vulgaris, Cell-Walls, Ions, Biomass, Cadmium, Equilibria, Binding, Zinc

Huh, J.K., Song, D.I. and Jeon, Y.W. (1999), Dual-mode sorption model for single-and multisolute sorption onto organoclays. Separation Science and Technology, 34 (4), 571-586.

Full Text: S\Sep Sci Tec34, 571.pdf

Abstract: The dual-mode sorption model (DSM) was applied to the single-solute sorption of 2-chlorophenol, 3-cyanophenol, and 4-nitrophenol from water onto organoclays. The three parameters contained in the DSM were determined for each solute by fitting to the single-solute isotherm data and subsequently utilized in competitive multisolute sorptions. A systematic method to determine the parameters for each solute was also suggested. The ideal adsorbed solution theory (IAST) coupled with the single-solute DSM and the competitive dual-mode sorption model (CDSM) extended to describe multisolute sorption were used to predict multisolute sorption onto organoclays and compared with the data to determine the predictive capabilities. The DSM was found to describe well single-solute sorption from water onto organoclays. The predictions from the CDSM and the IAST based on the DSM, though rather poor for some solutes, were generally in agreement with the multisolute sorption data. However, we could not tell at this stage which of the two competitive models is better.

Katoh, M., Katayama, K. and Tomida, T. (1999), Effect of temperature on air adsorption onto alkali metal ion-exchanged ZSM-5 zeolites. Separation Science and Technology, 34 (4), 599-608.

Full Text: S\Sep Sci Tec34, 599.pdf

Abstract: Alkali metal ion-exchanged ZSM-5 zeolites, M-ZSM-5 (M = Li, Na, K, Rb, and Cs), were prepared from Na-ZSM-5 by a conventional ion-exchange method, and their abilities to adsorb air were investigated through measurements of the amount of gases adsorbed as determined from elution curves on chromatography. The interaction of adsorbed gases and cations of M-ZSM-5 were examined from IR spectra of the adsorbed gases. It was found that the nitrogen in air was adsorbed selectively on M-ZSM-5 adsorbents, particularly Li-ZSM-5 and Na-ZSM-5 at room temperature. IR spectra indicated that nitrogen in air was adsorbed predominantly on cation sites in M-ZSM-5 zeolites owing to their strong interactions with these sites.

Keywords: Adsorption, ZSM-5 Zeolite, Air, Temperature

Aksu, Z. and Çalik, A. (1999), Comparative study of the biosorption of iron(III)-cyanide complex anions to Rhizopus arrhizus and Chlorella vulgaris. Separation Science and Technology, 34 (5), 817-832.

Full Text: S\Sep Sci Tec34, 817.pdf

Abstract: In this study a comparative biosorption of iron(III)-cyanide complex anions from aqueous solutions to Rhizopus arrhizus and Chlorella vulgaris was investigated. The iron(III)-cyanide complex ion-binding capacities of the biosorbents were shown as a function of initial pH, initial iron(III)-cyanide complex ion, and biosorbent concentrations. The results indicated that a significant reduction of iron(III)-cyanide complex ions was achieved at pH 13, a highly alkaline condition for both the biosorbents. The maximum loading capacities of the biosorbents were found to be 612.2 mg/g for R. arrhizus at 1996.2 mg/L initial iron(III)-cyanide complex ion concentration and 387.0 mg/g for C. Vulgaris at 845.4 mg/L initial iron(III)-cyanide complex ion concentration at this pH. The Freundlich, Langmuir, and Redlich-Peterson adsorption models were fitted to the equilibrium data at pH 3, 7, and 13. The equilibrium data of the biosorbents could be best fitted by all the adsorption models over the entire concentration range at pH 13.

Keywords: Iron(III)-Cyanide Complex Anions, Rhizopus arrhizus, Chlorella vulgaris, Biosorption, Batch Stirred Reactor, Aqueous-Solutions, Adsorption, Equilibrium, Cyanides, Removal, Dyes

Park, G.I., Park, H.S. and Woo, S.I. (1999), Influence of pH on the adsorption of uranium ions by oxidized activated carbon and chitosan. Separation Science and Technology, 34 (5), 833-854.

Full Text: S\Sep Sci Tec34, 833.pdf

Abstract: The adsorption characteristics of uranyl ions on surface-oxidized carbon were com pared with those of powdered chitosan over a wide pH range. In particular, an extensive analysis was made on solution pH variation during the adsorption process or after adsorption equilibrium. Uranium adsorption on the two adsorbents was revealed to be strongly dependent on the initial pH of the solution. A quantitative comparison of the adsorption capacities of the two adsorbents was made, based on the isotherm data obtained at initial pH 3, 4, and 5. In order to analyze the adsorption kinetics incorporated with pH effects, batch experiments at various initial pH values were carried out, and solution pH profiles with the adsorption lime were also evaluated. The breakthrough behavior in a column packed with oxidized carbon was also characterized with respect to the variation of effluent pH. Based on these experimental results, the practical applicability of oxidized carbon for uranium removal from acidic radioactive liquid waste was suggested.

Keywords: Aqueous-Solutions, Removal, Water

Subramaniam, K., Yiacoumi, S. and Tsouris, C. (1999), Effect of copper and cadmium binding on flocculation of ferric oxide particles. Separation Science and Technology, 34 (6-7), 1301-1318.

Full Text: S\Sep Sci Tec34, 1301.pdf

Abstract: The sorption of copper and cadmium ions from aqueous solutions by ferric oxide particles was studied using batch equilibrium and kinetic experiments. The sorption process was found to be pH dependent, with the uptake increasing at high pH values. An increase in equilibrium pH was observed when the initial pH was in the acidic range, and a decrease from initial values was observed in the basic range, in the case of both copper and cadmium sorption. The former phenomenon is due to competition between metal and proton binding, and the latter is due to precipitation mechanisms at high initial pH values. A large increase in the zeta potential of the particles from baseline values was observed during equilibrium sorption. This increase occurs as a result of surface charge neutralization due to metal ion uptake. Particle destabilization appears to occur as a result of metal ion sorption. Kinetic experiments indicate that the uptake of copper by Ferric oxide particles is a slow process. The pH histories were similar to those obtained in the sorption equilibrium experiments. Changes in the size distribution of the ferric oxide particles due to aggregate formation during uptake of ions were observed in the kinetic studies. These findings indicate a potential role of metal ion uptake in particle flocculation kinetics through alteration of the surface electrostatic potential.

Seco, A., Marzal, P., Gabaldón, C. and Ferrer, J. (1999), Study of the adsorption of Cd and Zn onto an activated carbon: Influence of pH, cation concentration, and adsorbent concentration. Separation Science and Technology, 34 (8), 1577-1593.

Full Text: 1999\Sep Sci Tec34, 1577.pdf

Abstract: The single adsorption of Cd and Zn from aqueous solutions has been investigated on Scharlau Ca 346 granular activated carbon in a wide range of experimental conditions: pH, metal concentration, and carbon concentration. The results showed the efficiency of the activated carbon as sorbent for both metals. Metal removals increase on raising the pH and carbon concentration, and decrease on raising the initial metal concentration. The adsorption processes have been modeled using the surface complex formation (SCF) Triple Layer Model (TLM). The adsorbent TLM parameters were determined. Modeling has been performed assuming a single surface bidentate species or an overall surface species with fractional stoichiometry. The bidentate stoichiometry successfully predicted cadmium and zinc removals in all the experimental conditions. The Freundlich isotherm has been aso checked.

Keywords: Single, Complexation, Removal, Systems, Activated Carbon, Adsorption, Cadmium, Zinc, Triple Layer Model

Yu, Q.M. and Kaewsarn, P. (1999), Binary adsorption of copper(II) and Cadmium(II) from aqueous solutions by biomass of marine alga Durvillaea potatorum. Separation Science and Technology, 34 (8), 1595-1605.

Full Text: 1999\Sep Sci Tec34, 1595.pdf

Abstract: Much work on the biosorption of heavy metals by low-cost, natural bionnass has been on the uptake of single metals. In practice, wastewaters often contain multiple heavy metal ions. In this paper the binary adsorption of copper(II) and Cadmium(II) by a pretreated biomass of the marine alga Durvillaea potatorum from aqueous solutions was studied. The results showed that the uptake capacities for each heavy metal of the binary system were lower when compared with the single metal biosorption for copper and cadmium, respectively, but the total capacities for the binary system were similar to those obtained for single metal biosorption. The uptake capacities for copper and cadmium increased as the equilibrium pH increased and reached a plateau at a pH around 5.0. The uptake process was relatively fast, with 90% of the adsorption completed within 10 minutes for copper and 30 minutes for cadmium, and equilibrium reached after about 60 minutes of stirring. The biosorption isotherms of binary systems were not significantly affected by equilibrium temperature. The presence of light metal ions in solution also did not affect adsorption significantly. The binary adsorption was successfully predicted by the extended Langmuir model, using parameters and capacities obtained from single component systems.

Keywords: Heavy-Metal Biosorption, Competitive Adsorption, Removal, Water, Ions, Biosorbents, Binding, Radiata, Lead, Zn, Biosorption of Heavy Metals, Binary Adsorption, Copper, Cadmium, Durvillaea potatorum, Marine Algae

Chang, J.S. and Chen, C.C. (1999), Biosorption of lead, copper, and cadmium with continuous hollow-fiber microfiltration processes. Separation Science and Technology,