Personal Research Database

Full Text: 2005\Sep Sci Tec40, 1797.pdf

Abstract: Batch adsorption experiments were conducted in the laboratory, aiming to the removal of aluminum from aqueous solutions onto powdered marble wastes (PMW) as an effective inorganic sorbent, which is inexpensive, widespread, and may represent an environmental problem. The main parameters (i.e., initial solution pH, sorbent and Al³⁺ ions concentrations, stirring times and temperature) influencing the sorption process in addition to the effect of some foreign ions was examined. The results obtained revealed that the sorption of Al³⁺ ions onto PMW is endothermic in nature and followed first-order kinetics. The adsorption data were well described by the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption models over the concentration range studied. Under the optimum experimental conditions employed, the removal of ca. 100% of Al³⁺ ions was attained. The procedure was successfully applied to the removal of aluminum from aqueous and different natural water samples with an RSD (%), does not exceed 2.12%. Moreover, the adsorption mechanism is suggested.

Keywords: Aluminum, Sorption, Powdered Marble Wastes, Natural Waters, Aqueous-Solutions, Hexavalent Chromium, Activated Carbon, Drinking-Water, Oleic-Acid, Fly-Ash, Ions, Copper(II), Flotation, Sorption

? Rao, P.S., Kalyani, S., Suresh Reddy, K.V.N. and Krishnaiah, A. (2005), Comparison of biosorption of nickel(II) and copper(II) ions from aqueous solution by Sphaeroplea algae and acid treated Sphaeroplea algae. Separation Science and Technology, 40 (15), 3149-3165.

Full Text: 2005\Sep Sci Tec40, 3149.pdf

Abstract: Biosorption of nickel(II) and copper(II) ions from aqueous solution by dead sphaeroplea algae in natural and acid treated forms were studied as a function of concentration, pH, and adsorbent dose. The optimum pH for nickel(II) and copper(II) biosorption was found to be 6.0 and 4.0 respectively. The metal ion uptake increased with initial metal ion concentration studied up to 500 mg/L. Both the Freundlich and Langmuir adsorption models could fit the equilibrium data. The adsorption reasonably fitted the Lagergren kinetic model. Further the biomass was characterized by FTIR spectra. Surface area values are measured to be 0.9 and 2.1 m²/g for natural and acid treated forms respectively. The maximum adsorption capacity was found to be 3.40, 4.15 mmol/g for nickel(II) and 2.21, 3.41 mmol/g for copper(II) in natural and acid treated forms respectively.

Keywords: Green Algae, Biosorption, Nickel, Copper, FTIR, Waste Water, Metal-Ions, Adsorption, Biomass, Lead, Equilibrium, Removal, Cadmium, Cu(II), Zinc

? Petkovska, M. and Petkovska, L.T. (2006), Application of nonlinear frequency response to investigation of membrane transport. Separation Science and Technology, 41 (1), 43-72.

Full Text: 2006\Sep Sci Tec41, 43.pdf

Abstract: The concept of higher order frequency response functions, used for investigation of weekly nonlinear systems by frequency response techniques, is applied to investigation of membrane systems. Isothermal permeation of single gases through non-porous and porous membranes is analysed for three transport mechanisms: solution-diffusion, pore-surface diffusion, and viscous-flow. In the course of definition of the transmembrane transport in dynamic conditions, a new concept of generalized membrane permeability, defined as an indefinite sequence of the permeabilities of the first, second, third,...order, dependent on the equilibrium and transport parameters of the membrane in steady-state, is introduced. A simple two-reservoir system, with variation of the volume of one reservoir, is defined and its first and second order frequency response functions are derived. It is shown that these functions can be used for identification of the transport mechanism, i.e., of the corresponding model and for estimation of the model parameters: permeabilities of different orders, as well as the separate values of the relevant equilibrium and transport parameters.

Keywords: Membrane Transport, Nonlinear Frequency Response, Higher Order Frequency Response Functions, Generalized Membrane Permeability, Solution-Diffusion Model, Pore-Surface Diffusion Model, Viscous-Flow Model, Parameter Estimation, Adsorption-Kinetics, Diffusion, Systems, Mechani

? Modrzejewska, Z., Sujka, W., Dorabialska, M. and Zarzycki, R. (2006), Adsorption of Cr(VI) on cross-linked chitosan beads. Separation Science and Technology, 41 (1), 111-122.

Full Text: 2006\Sep Sci Tec41, 111.pdf

Abstract: A possibility of Cr(VI) removal by the adsorption method is discussed in the paper. An adsorbent were hydrogel chitosan beads are produced by the phase inversion method (by changing pH). The possibility of removing Cr(VI) ions by both pure chitosan hydrogel and its chelate compounds (chitosan cross-linked with Cu(II) and Ag(I) ions) was investigated. The adsorption proceeded from the solutions of potassium dichromate and ammonium dichromate (NH₄)₂Cr₂O₇ and K₂Cr₂O₇. The process rates and adsorption isotherms were determined and described by relevant equations. The process rate was described by the pseudo- and second-order equations, and adsorption equilibria by the Langmuir equations. A slight advantageous change in adsorption properties of chitosan beads was revealed after cross-linking (for chromium concentration up to 10 g/dm³). A maximum adsorption was 1.1 g(Cr)/g chitosan. Results of the studies show that chitosan hydrogel proves useful in the removal of Cr(VI) ions, additionally, cross-linking with Cu(II) and Ag(I) ions has an advantageous effect in the case of low-concentrated solutions.

Keywords: Chitosan, Adsorption, Cr(VI) Ions, Heavy-Metal Ions, Waste-Water, Removal, Separation, Sorbents, Equilibrium, Adsorbents, Membranes, Sorption, Silver

? Basso, M.C. and Cukierman, A.L. (2006), Wastewater treatment by chemically activated carbons from giant reed: Effect of the activation atmosphere on properties and adsorptive behavior. Separation Science and Technology, 41 (1), 149-165.

Full Text: 2006\Sep Sci Tec41, 149.pdf

Abstract: Uptake of nickel and benzene from dilute single-solute solutions, mimicking wastewater with low concentrations of heavy metals or volatile organic compounds, was examined using activated carbons with similar good surface properties (BET surface area of approximate to 1100 m²/g). They were developed through H₃PO₄ acid activation of giant reed (Arundo donax L.) under flowing air or N₂. The carbons obtained in air proved more effective to capture Ni(II) ions under pre-established equilibrium conditions. Inversely, the N₂-derived carbons exhibited a better ability for benzene adsorption. The behavior was related to the smaller total content of acidic/polar surface oxygen functionalities of the carbons developed under N₂ (1.9 meq/g), compared to that of the air-derived ones (3.3 meq/g). Two-, three-parameter models described properly the isotherms, predicting similar maximum adsorption capacities (X_m) for the investigated systems. The X_m parameter in the Langmuir’s model was 0.44 mmol/g for the adsorption of Ni(II) ions on the air-derived carbons, and 0.45 mmol/g for benzene adsorption on those obtained in N₂. Present results highlight the relevance of the surface chemistry developed upon activation to optimize the performance of activated carbons for wastewater treatment according to the pollutants’ nature.

Keywords: Wastewater Treatment, Activated Carbons, Heavy Metals, Volatile Organic Compounds, Lignocellulosic Materials, Functional-Groups, Phosphoric-Acid, Arundo-Donax, Shell, Dioxide, Metals, Lignin, Ions, Wood

? Sauer, T.P., Casaril, L., Oberziner, A.L.B., Soares, J.L. and Moreira, R.D.P.M. (2006), Modeling of adsorptive filtration of a leather dye in a fixed bed column. Separation Science and Technology, 41 (3), 501-513.

Full Text: 2006\Sep Sci Tec41, 501.pdf

Abstract: Activated carbons offer an efficient option for the removal of organic and inorganic contaminants from water. However, due to its high costs and difficulty in the regeneration, other low cost adsorbents have been used. In this work, the adsorption capacity of an adsorbent carbon with high iron oxides concentration was compared with that of a commercial activated carbon in the removal of a leather dye from an aqueous solution. The adsorbents were characterized using SEM/EDAX analysis and BET surface area. The capacity of adsorption of the adsorbents was evaluated through the static method at 25°C. The results showed that the color removal was due to the adsorption and precipitation of the dye on the surface of the solids. The adsorption equilibrium was described according to the linear model for the adsorbent carbon and the equilibrium constant was 0.02 L g^-1. The equilibrium of adsorption on activated carbon exhibited a behavior typical of the Langmuir isotherm and the monolayer coverage was 24.33 mg g^-1. A mathematical model was proposed to describe the dynamics of the color removal using a fixed bed considering that the color removal is due to the adsorption and the precipitation of the dye on the adsorbent.

Keywords: Activated Carbons, Adsorption, Color Removal, Dye, Ions, Iron, Langmuir, Modeling, Removal, Surface, Water, Water Treatment

? Onyango, M.S., Kojima, Y., Kumar, A., Kuchar, D., Kubota, M. and Matsuda, H. (2006), Uptake of fluoride by Al³⁺ pretreated low-silica synthetic zeolites: Adsorption equilibrium and rate studies. Separation Science and Technology, 41 (4), 683-704.

Full Text: 2006\Sep Sci Tec41, 683.pdf

Abstract: The removal of fluoride from single component aqueous solution using Al³⁺ - pretreated low-silica synthetic zeolites (Al-Na-HUD, Al-HUD, Al-F9, and Al-A4) was studied. The effects of adsorbent mass, initial solution pH, and initial concentration on fluoride removal in a batch system were evaluated. Equilibrium data were simulated using simple isotherms such as the Freundlich (F), Langmuir-Freundlich (LF), Redlich-Peterson (RP) and Dubinin-Radushkevitch (DR) isotherms. From the DR model, initial pH effects and desorption studies, it was considered that the fluoride adsorption onto the zeolites proceeded by ion-exchange or chemisorption mechanism. In interpreting the kinetic results, reaction kinetics (using Elovich equation) and mass transfer processes (both external mass transfer and intraparticle diffusion) were considered. Equilibrium and kinetic results of fluoride adsorption onto the adsorbents demonstrated the following order of performance: Al-Na-HUD>Al-F9> Al-HUD>Al-A4.

? Dias, N.L., do Carmo, D.R. and Rosa, A.H. (2006), Selective sorption of mercury(II) from aqueous solution with an organically modified clay and its electroanalytical application. Separation Science and Technology, 41 (4), 733-746.

Full Text: 2006\Sep Sci Tec41, 733.pdf

Abstract: The organo-clay used in this work was prepared from a Na-montmorillonite (Wyoming-USA deposit) by treatment with water solution of hexadecyltrimethylammonium cations. As organo-clays exhibit strong sorptive capabilities for organic molecules, 2-mercapto-5-amino-1,3,4-thiadiazole organofunctional groups, with potential usefulness in chemical analysis, were incorporated on its solid surface. The physically adsorbed reagent did not present any restrictions in coordinating with several metal ions on the surface. The resultant organo-clay complex exhibited strong sorptive capability for removing mercury ions from water in which other metals and ions were also present. The purpose of this work is to study the selective separation of mercury(II) from aqueous solution using the organo-clay complex, measured by batch and chromatographic column techniques, and its application as preconcentration agent in a chemically modified carbon paste electrode for determination of mercury(II) in aqueous solution.

Keywords: 2-Mercaptoimidazole, Adsorption, Adsorption, Analysis, Carbon, Carbon Paste Electrode, Chemical, Chemical Analysis, Clay, Complex, Complexes, Determination, Hexadecyltrimethylammonium, Industrial Wastewaters, Inorgano-Organo-Clays, Ion-Exchange Voltammetry, Mercury, Mercury(II), Metal Ions, Metals, Modified, Modified Clay, Modified Electrodes, Montmorillonite, Montmorillonite, Organic, Organic Molecules, Organo-Clay, Organo-Clays, Organoclay, Organoclays, Preconcentration, Priority Pollutants, Selective, Separation, Silica-Gel Surface, Sorption, Surface, Techniques, Treatment, Water

? Wang, X.S., Qin, Y. and Li, Z.F. (2006), Biosorption of zinc from aqueous solutions by rice bran: Kinetics and equilibrium studies. Separation Science and Technology, 41 (4), 747-756.

Full Text: 2006\Sep Sci Tec41, 747.pdf

Abstract: Rice bran, an agricultural by-product, was used for the removal of zinc ions from aqueous solution. The work considered the determination of zinc-biomass equilibrium data in batch system. These studies were carried out in order to determine some operational parameters of zinc sorption such as the time required for the Zinc-biosorbent equilibrium, the effects of biomass particle size, pH, and temperature. The results showed that pH has an importance effect on zinc biosorption capacity. The biosorbent size also affects the zinc biosorption capacity. The sorption process follows pseudo-second-order kinetics. The intraparticle diffusion may be the rate-controlling step involved in the adsorption zinc ions onto the rice bran up to 30 min. The equilibrium data could be best fitted by the Langmuir sorption isotherm equation over the entire concentration range (40-160 mg/dm³). Thermodynamic parameters, such as Delta G degrees, Delta H degrees, Delta S degrees, have been calculated. The thermodynamics of zinc ion/rice bran system indicate spontaneous and endothermic nature of the process.

Keywords: Biosorption, Zinc(II), Rice Bran, Adsorption Kinetic, Langmuir Isotherm, Thermodynamic Property, Metal-Ions, Tree Fern, Sorption, Removal, Copper, Chromium(III), Biomass, Wastes, Nickel

? Nassar, M.M. (2006), Adsorption of Fe⁺³ and Mn⁺² from ground water onto maize cobs using batch adsorber and fixed bed column. Separation Science and Technology, 41 (5), 943-959.

Full Text: 2006\Sep Sci Tec41, 943.pdf

Abstract: The removal of iron and manganese from ground water is an important step for producing safe drinking water. A detailed investigation of the sorption of iron and manganese from ground water onto maize cobs is reported. This work deals with determination of adsorption equilibrium isotherms, kinetic, and fixed bed column studies. Results of Freundlich and Langmiur parameters revealed the favorability of maize cobs for adsorption of iron and manganese ions. Kinetic studies were carried out using from ground water samples (El-Mina Governorate, Egypt). From the kinetic studies, a model is proposed to determine the external mass transfer (Ks) which can be correlated by the following equation Ks =A (mass) B . where A and B are constants. During the fixed bed column studies, the effect of process variables such as bed height, flow rate, initial concentration, and percentage breakthrough has been investigated. A simplified design method, namely, the bed depth service time (BDST) model has been applied to the experimental data and the results of this analysis are presented. The mechanism of the metal ion sorption on maize cobs was also investigated. Both the calorific values and differential thermal analysis (DTA) data proved that the loaded maize cobs can be used as solid fuel. Pretences of iron and manganese salts catalyze the thermal decomposition reaction toward more flammable gases, which increase their calorific values. The loaded maize cobs are considered a new potential source for energy conversion.

Keywords: Adsorption, Adsorption Equilibrium Isotherms, Aqueous-Solutions, Bagasse Pith, BDST, Diffusion, Dyes, Fired Bed Column Studies, Ground Water, Iron And Manganese Removal, Kinetic Studies, Maize Cobs, Palm-Fruit Bunch, Pore, Removal, Sorption

? Northcott, K., Kokusen, H., Komatsu, Y. and Stevens, G. (2006), Synthesis and surface modification of mesoporous silicate SBA-15 for the adsorption of metal ions. Separation Science and Technology, 41 (9), 1829-1840.

Full Text: 2006\Sep Sci Tec41, 1829.pdf

Abstract: In this study surface modified SBA-15, coated with octadecyltrichlorosilane (C18), is considered as an alternative adsorbent for metal ions in water. The SBA-C18 was loaded with Bis(2,4,4-trimethylpentyl) phosphinic acid (cyanex 272) as the metal ion extractant. The adsorption characteristics of phosphinic acid loaded SBA-C18 were evaluated for Cu(II) and Zn(II) ions in aqueous solution. Adsorption tests indicated that a contact time of 1 hour was sufficient for adsorption equilibrium to occur. The pH 1/2 values of Zn(II) and Cu(II) onto SBA-C18, were found to be similar to published data for levextrel ion exchange resins and around 1 pH unit lower than published solvent extraction data for cyanex 272 in xylene.

Keywords: Acid, Adsorbent, Adsorption, Adsorption Equilibrium, C18, Equilibrium, Extraction, Ion, Ion Exchange, Mesoporous Silicate, Metal Ions, Modification, Modified, Molecular-Sieves, pH, Resins, SBA-15, Separation, Silicate, Solvent Extraction, Surface, Surface Modification, Water, Zn(II)

? Bhatnagar, A., Jain, A.K., Minocha, A.K. and Singh, S. (2006), Removal of lead ions from aqueous solutions by different types of industrial waste materials: Equilibrium and kinetic studies. Separation Science and Technology, 41 (9), 1881-1892.

Full Text: 2006\Sep Sci Tec41, 1881.pdf

Abstract: A comparative study of the adsorbents prepared from several industrial wastes for the removal of Pb²⁺ has been carried out. Fertilizer industry waste viz. carbon slurry and steel plant wastes viz. blast furnace (B.F.) slag, dust, and sludge were investigated as low-cost adsorbents after proper treatment in the present study. The adsorption of Pb²⁺ on different adsorbents has been found in the order: B.F. sludge > B.F. dust > B.F. slag > carbonaceous adsorbent. The least adsorption of Pb²⁺ on carbonaceous adsorbent even having high porosity and consequently greater surface area as compared to other three adsorbents, indicates that surface area and porosity are not important factors for Pb²⁺ removal from aqueous solutions. The adsorption of Pb²⁺ has been studied as a function of contact time, concentration, and temperature. The adsorption has been found to be exothermic, and the data conform to the Langmuir equation. The kinetic results reveal that the present adsorption system follows Lagergren’s first order rate equation. Since all three waste products from the steel industry show higher potential to remove lead from water, therefore, it is suggested that these metallurgical wastes can be fruitfully employed as low-cost adsorbents for effluent treatment containing toxic metal ions.

Keywords: Steel Plant Wastes, Fertilizer Industry Waste, Low-Cost Adsorbents, Lead Removal, Equilibrium and Kinetic Studies, Blast-Furnace Sludge, Low-Cost Adsorbent, Heavy-Metals, Sorption, Water, Slag, Adsorption, Peat

? Rains, W.O. and Counce, R.M. (2006), Liquidus curves of NH₄NO_3(aq) calculated from the modified adsorption isotherm model for aqueous electrolytes. Separation Science and Technology, 41 (11), 2629-2634.

Full Text: 2006\Sep Sci Tec41, 2629.pdf

Abstract: The Stokes-Robinson modification of the Brunauer-Emmett-Teller (BET) adsorption isotherm is used to calculate the liquidus curve of NaNO_3(aq) including the eutectic point and metastable phases. The method described here represents a simplified approach to predict the liquidus curves with sparse information and considers the presence of several crystalline solid phases of NH₄NO₃.

Keywords: Absorption Isotherm, Activity Coefficients, Adsorption, Adsorption Isotherm, Adsorption Isotherm Model, Aqueous Electrolyte, BET Model, Brunauer-Emmett-Teller (BET), Concentrated-Solutions, Electrolytes, Eutectic, Information, Isotherm, Model, Modification, Modified, Predict, Salt, Water

? Srivastava, V.C., Mall, I.D. and Mishra, I.M. (2006), Modelling individual and competitive adsorption of cadmium(II) and zinc(II) metal ions from aqueous solution onto bagasse fly ash. Separation Science and Technology, 41 (12), 2685-2710.

Full Text: 2006\Sep Sci Tec41, 2685.pdf

Abstract: The present study deals with the competitive adsorption of cadmium (Cd(II)) and zinc (Zn(II)) ions onto bagasse fly ash (BFA) from binary systems. BFA is a waste obtained from the bagasse-fired boilers of sugar mills. The initial pH approximate to 6.0 is found to be the optimum for the individual removal of Cd(II) and Zn(II) ions by BFA. The equilibrium adsorption data were obtained at different initial concentrations (C-0 = 10-100 mg/l), 5 h contact time, 30°C temperature, BFA dosage of 10 mg/l at pH(0) = 6. The Redlich-Peterson (R-P) and the Freundlich models represent the single ion equilibrium adsorption data better than the Langmuir model. The adsorption capacities in the binary-metal mixtures are in the order Zn(II)> Cd(II) and is in agreement with the single-component adsorption data. The equilibrium metal removal decreases with increasing concentrations of the other metal ion and the combined action of Cd(II) and Zn(II) ions on BFA is found to be antagonistic. Equilibrium isotherms for the binary adsorption of Cd(II) and Zn(II) ions on BFA have been analyzed by non-modified Langmuir, modified Langmuir, extended-Langmuir, Sheindorf-Rebuhn-Sheintuch (SRS), non-modified R-P and modified R-P adsorption models. The isotherm model fitting has been done by minimizing the Marquardt’s percent standard deviation (MPSD) error function using MS Excel. The SRS model satisfactory fits for most of the adsorption equilibrium data of Cd(II) and Zn(II) ions onto BFA.

Keywords: Binary Adsorption, Bagasse Fly Ash (BFA), Simultaneous Metal Removal, Multi-Component Isotherms, Cadmium(II), Zinc(II), Equilibrium Isotherm Analyses, Freundlich-Type Isotherm, Activated Carbon, Multicomponent Isotherm, Removal, Biosorption, Waste, Biomass, Zn(II), Water

? Deng, S.B., Yu, G. and Ting, Y.P. (2006), Removal of humic acid using PEI-modified fungal biomass. Separation Science and Technology, 41 (13), 2989-3002.

Full Text: 2006\Sep Sci Tec41, 2989.pdf

Abstract: A modified fungal biomass was prepared through the adsorption of polyethylenimine (PEI) and subsequent crosslinking with glutaraldehyde on the biomass surface. FTIR result verified that the amine groups were introduced on the biomass surface. As a large number of amine groups are present on the biomass surface and can be protonated in solution, the modified biomass was positively charged at pH < 10.3. The modified biomass was used as an adsorbent to remove humic acid in a series of batch adsorption experiments. The amount of humic acid adsorbed on the biosorbent decreased with increasing solution pH, and the electrostatic interaction between the positive protonated amine groups on the biomass surface and the negative carboxyl groups in the humic acid molecules played an important role in humic acid adsorption. The time-dependent sorption of humic acid on the biomass can be described well by the Fickian diffusion model at the initial stage and the pseudo-second-order equation over 10 h. Using the Langmuir adsorption isotherm, the maximum sorption capacity of the modified biomass for humic acid at pH 5 was 96.5 mg/g. The desorption experiments showed that the humic acid loaded biomass could be easily regenerated in a 0.1 M NaOH solution, and the regenerated biomass possessed good adsorption capacity up to the fifth cycle. The PEI-modified biomass with polyamine chains shows the potential for application in water treatment for the removal of humic substances.

Keywords: PEI-Modified Biomass, Zeta Potential, Adsorption Behavior, Humic Acid, Ftir Analysis, Aminated Polyacrylonitrile Fibers, Natural Organic-Matter, Mineral Particles, Metal-Ions, Adsorption, Sorption, Ultrafiltration, Biosorption, Mechanisms, Trivalent

? Wen, D.H., Ho, Y.S., Xie, S.G. and Tang, X.Y. (2006), Mechanism of the adsorption of ammonium ions from aqueous solution by a Chinese natural zeolite. Separation Science and Technology,