Personal Research Database

Full Text: 1999\Sep Sci Tec34, 1607.pdf

Abstract: A hollow-fiber crossflow microfiltration membrane was utilized to retain a biomass of Pseudomonas aeruginosa PU21 for continuous biosorption of lead (Pb), copper (Cu), and cadmium (Cd) ions in single or ternary metalsystems. The results obtained from the microfiltration systems showed that in both single and ternary biosorption, the metal removal efficiency based on a molar basis war, clearly Pb > Cu > Cd. For a single-membrane process with an influent metal concentration of 200 µM and a flow rate of 350 mL/h, the effluent concentration of Pb and Cu satisfied the national regulations for an influent volume of 6.3 L. With a three-metal influent, the adsorption capacity of the biomass for Pb, Cu, and Cd was reduced 4, 50, and 74% compared to that for single-metal adsorption. Selective biosorption with a three-column sequential microfiltration operation exhibited an enhancement of 40 and 57% of total metal removal for Cu and Cd, respectively, over the results from single-membrane operation. The multimembrane operation also enabled locally optimal accumulation of Pb, Cu, and Cd at the first, second, and third stage, respectively. The regeneration efficiency of the biomass was 70% after three repetitive adsorption/desorption cycles, whereas the Pb recovery efficiency was maintained at nearly 90%. A rapid-equilibrium model (Model A) and a mass-transfer model (Model B) were used to describe the results of single-and multimetal biosorption with the microfiltration processes. Model A exhibited excellent prediction for the results of single-metal biosorption, while Model B was more applicable to interpret the multimetal biosorption data.

Keywords: Pseudomonas-Aeruginosa PU21, Heavy-Metals, Removal, Adsorption, Column, Cells, Biosorption, Microfiltration, Hollow Fiber, Heavy Metals, Multimetal Adsorption

Bialopiotrowicz, T., Blanpain-Avet, P. and Lalande, M. (1999), Characterization of inorganic carbon-supported microfiltration and ultrafiltration membranes by aqueous phenol adsorption. Separation Science and Technology, 34 (9), 1803-1818.

Full Text: S\Sep Sci Tec34, 1803.pdf

Abstract: The adsorption of phenol on inorganic carbon-supported microfiltration and ultrafiltration membranes has been determined. Using the statistical Student’ s t-test, it has been shown that phenol adsorption data are well fitted to the Langmuir and BET isotherm equations. It was thus concluded that the adsorption of phenol was monomolecular and that the specific surface area (SSA) calculated from these data was essential. M1 and M2 ultrafiltration membranes were found to have a higher SSA than microfiltration M14 and carbon support membranes. Assuming that a simple model of the porous structure consisted of a packed bed of spherical particles, it was possible to determine an apparent average pore diameter from SSA data using the Carman-Kozeny equation. The SSA determined from phenol adsorption was found to be close to that measured from mercury porosimetry for the microfiltration membrane and carbon support. Such a result is due to the fact that there is a common basis between the Carman-Kozeny equation employed in the adsorption method and the determination of the ratio 4V/A (V = total porous volume, A = total pore area) in the mercury porosimetry method (as both methods consider a constant volume/surface ratio of the pores along the microporous membrane thickness).

Keywords: Phenol Adsorption, Specific Surface Area, Membrane Support Characterization, Inorganic Membranes

Juang, R.S., Shiau, J.Y. and Shao, H.J. (1999), Effect of temperature on equilibrium adsorption of phenols onto nonionic polymeric resins. Separation Science and Technology, 34 (9), 1819-1831.

Full Text: S\Sep Sci Tec34, 1819.pdf

Abstract: The amounts of equilibrium adsorption of phenol and 4-chlorophenol from aqueous solutions on nonionic polymeric resins were measured in the 288-318 K temperature range. In general, these polymeric resins have a higher capacity for 4-chlorophenol at low solute concentrations but for phenol at higher solute concentrations. The adsorption data for both phenols were presented in terms of the number of adsorbed monolayers and the fraction of pore volume filled due to poor fit by the widely used Langmuir, Freundlich, and BET equations over the entire concentration range (100-3000 g/m³). Finally, the isosteric enthalpies of adsorption were determined. They decreased with increasing surface coverage.

Keywords: Equilibrium Adsorption, Phenol, 4-Chlorophenol, Nonionic Polymeric Resins, Temperature Effect, Aqueous-Solution, Carboxylic-Acids, Sorption, Adsorbents, Organics

Chern, J.M. and Huang, S.N. (1999), Study of nonlinear wave propagation theory. II. Interference phenomena of single-component dye adsorption waves. Separation Science and Technology, 34 (10), 1993-2011.

Full Text: S\Sep Sci Tec34, 1993.pdf

Abstract: Yellow acid dye was adsorbed from aqueous solution by granular activated carbon packed in a column. The feed concentration was kept constant for a period of time and then switched to another level to simulate the concentration variation in wastewater treatment processes. The resulting breakthrough curves were experimentally measured and theoretically predicted. Explicit equations and an algorithm were developed based on the wave interference theory to predict the column breakthrough curves of single-component adsorption processes with step change in the feed concentration. The experimental results show that the wave interference theory predicts the column breakthrough curves satisfactorily.

Keywords: Activated Carbon, Aqueous-Solutions, Mass-Transfer, Chromatography, Dyestuffs, Removal, Wave Propagation, Fixed-Bed Dynamics, Dye, Activated Carbon, Adsorption, Wave Interference

? Kocjan, R. and Swieboda, R. (1999), Silica gel treated with a mixture of Aliquat 336 and Acid Alizarin Violet N and its application. Separation Science and Technology, 34 (13), 2571-2582.

Full Text: 1999\Sep Sci Tec34, 2571.pdf

Abstract: Acid Alizarin Violet N is strongly extracted by chloroform solutions of Aliquat 336 by an ion-exchange mechanism. Relatively high concentrations of mineral acids are required for its reextraction from the ion pair formed. By impregnation of silica with ion pairs composed of the cation of Aliquat 336 and the anion of the dye, a chelating sorbent for metal ions can be obtained. The sorbent prepared may be successfully used for the separation of mixtures of various metal ions by the column extraction chromatography technique, for additional purification of sodium and potassium salts from the ions of heavy metals, and for the concentration of trace amounts of ions of various metals from aqueous solutions followed by their quantitative determination. The sorbent can be used repeatedly for the sorption and desorption of metal ions (especially those forming less stable complexes with the reagent) after regeneration with solutions of chloric(VII) acid. The effect of hydrophobicity of the chelating reagent on the stability of its ion pair with the tetraalkylammonium cation has been confirmed. Acid Alizarin Violet N forms less stable ion pairs with Aliquat 336 than the more hy drophobic Calmagit.

Keywords: Desorption, Dye, Heavy Metals, Ion Exchange, Metals, Preconcentration, Regeneration, Salts, Sorbent, Sorption

Porras, M. and Talens, F.I. (1999), Removal of 2,4-d from aqueous solutions by micellar flocculation. Separation Science and Technology, 34 (13), 2679-2684.

Full Text: S\Sep Sci Tec34, 2679.pdf

Abstract: This paper describes removal of the pesticide 2,4-dichlorophenoxyacetic acid from aqueous solutions by sorption on aggregates formed by flocculation of micelles of the anionic surfactant sodium lauryl sulfate with aluminum sulfate. The micelles aggregate in a single flee containing all the micellar surfactant, and this flee is sufficiently consistent to be removed by filtration. This example illustrates the potential of micellar flocculation as a water treatment technique.

Keywords: Anionic, Surfactant, Separation, Micelle, Pesticide, Separation

Suhasini, I.P., Sriram, G., Asolekar, S.R. and Sureshkumar, G.K. (1999), Nickel biosorption from aqueous systems: Studies on single and multimetal equilibria, kinetics, and recovery. Separation Science and Technology, 34 (14), 2761-2779.

Full Text: S\Sep Sci Tec34, 2761.pdf

Abstract: This paper reports studies on the removal of toxic trace metals (nickel separately, and simultaneously with cobalt) from aqueous solutions by employing fungal biosorbents, PFB1 and PFB2, which were developed in our laboratory. The observed maximum equilibrium uptake of nickel on the biosorbent was 214 mg.g^-1 (PFB1) and 110 mg.g^-1 (PFB2). The average efficiency for nickel removal was 84.5% (PFB1) and 60.8% (PFB2). The equilibrium uptake of nickel followed first-order Langmuir kinetics in the case of PFB1 and second-order Langmuir kinetics in the case of PFB2. Studies on simultaneous removal of cobalt and nickel indicated that the extent of secondary interactions between cobalt and nickel can be quantified by the change in Langmuir equilibrium constants for both metals. A mathematical model based on Fick’s law of diffusion and Langmuir adsorption was developed to simulate the kinetics of nickel removal. The model was able to predict the experimentally observed kinetics well. From the simulations, the diffusivity of nickel in PFB1 was found to be 1.6×10^-8 m².s^-1. Desorption studies indicated that it was possible to reuse the biosorbent over three sorption-desorption cycles, and that acidic solutions desorbed better than basic or salt solutions. Among the desorbents studied, HCl and CaCl₂, with dt sorption efficiencies equal to 73.2 and 74.1%, respectively, for PFB1 and 70.0 and 63.1%, respectively, for PFB2 at the end of three cycles, were found to be the best desorbents.

Keywords: Biosorption, Nickel, Kinetics, Multimetal Equilibria, Desorption, Saccharomyces-Cerevisiae, Heavy-Metals, Biomass, Ions

? Kim, J.S. and Yi, J. (1999), The removal of copper ions from aqueous solutions using silica supports immobilized with 2-hydroxy-5-nonylacetophenoneoxime. Separation Science and Technology, 34 (15), 2957-2971.

Full Text: 1999\Sep Sci Tec34, 2957.pdf

Abstract: Silica supports immobilized with 2-hydroxy-5-nonylacetophenoneoxime (LIX 84) were prepared after surface modification by gamma-aminopropyltriethoxysilane. Three types of silica beads and a silica powder were used as supports. Batch and packed-column tests were conducted to investigate the capabilities of the prepared adsorbents to remove copper ions. A comparison of the different silica supports was performed with respect to copper adsorption capacity, copper adsorption rate, and nitrogen content. In addition, studies were carried out for the modified silica beads that showed highest copper ion removal capability among the three silica beads (SB2-L). The extraction rate of the SB2-L increases with solution pH in the range between pH 2 and 4. Stability tests show that the SB2-L is stable under acidic conditions. From regeneration experiments it was found that copper ions which are adsorbed at the surface of the SB2-L were recovered by washing with 0.1 M HNO3 and that the regenerated beads are reversible. The recovery ratios were between 80 and 90%. A breakthrough curve was obtained using modified silica powder (SP-L). The copper recovery ratio for SPL was 74%. The results show that the SP-L prepared is feasible for the extraction of copper ions from aqueous solutions using a fixed-bed reactor.

Keywords: Solvent-Extraction, Separation, Acid, Membranes, Recovery, Exchange, Phase, Resin, Lead

Khalid, N., Ahmad, S., Kiani, S.N. and Ahmed, J. (1999), Removal of mercury from aqueous solutions by adsorption to rice husks. Separation Science and Technology, 34 (16), 3139-3153.

Full Text: S\Sep Sci Tec34, 3139.pdf

Abstract: The adsorption of mercury ions from aqueous solutions on rice husk has been investigated as a function of appropriate electrolyte, contact time, concentrations of adsorbent and adsorbate, and temperature. The radiotracer technique was used to determine the distribution of mercury. Maximum adsorption was observed at 0.01 mol.dm^-3 acid solutions (HNO₃, HCl, H₂SO₄, and HClO₄) using 1.0 g of adsorbent for 1.3010^-3 mol.dm^-3 mercury concentration in 5 minutes of equilibration time. Studies show that the adsorption decreases with an increase in the concentrations of all the acids. The adsorption data follow the Freundlich isotherm over the range of 1.310^-4 to 2.610^-3 mol.dm^-3 mercury concentration. The characteristic Freundlich constants. i.e., 1/n = 0.890.05 and A = 208m.mol.g^-1, have been computed for the sorption system. The uptake of mercury increases with a rise in temperature. Thermodynamic parameters, i.e., Delta G degrees, Delta S degrees, and Delta H degrees, have also been calculated for the system. The sorption process was found to be endothermic. Application of the method to the effluents of medium-sized industries showed that 9.9 kg of rice husk was sufficient for their decontamination.

Keywords: Heavy-Metal Ions, Neutron-Activation, Radiotracer Technique, Efficient Removal, Zirconium-Oxide, Trace-Elements, Sea-Water, Behavior, Binding, Preconcentration

Sağ, Y., Ataçoğlu, I. and Kutsal, T. (1999), Simultaneous biosorption of chromium(VI) and copper(II) on Rhizopus arrhizus in packed column reactor: Application of the competitive Freundlich model. Separation Science and Technology, 34 (16), 3155-3171.

Full Text: S\Sep Sci Tec34, 3155.pdf

Abstract: The simultaneous biosorption of Cr(VI) and Cu(II) on free Rhizopus arrhizus in a packed column operated in the continuous mode was investigated and compared to the single metal ion situation. The breakthrough curves were measured as a function of feed flow rate, feed pH, and different combinations of metal ion concentrations in the feed solutions. Column competitive biosorption data were evaluated in terms of the maximum (equilibrium) capacity of the column, the amount of metal loading on the R. arrhizus surface, the adsorption yield, and the total adsorption yield. In the single-ion situation the adsorption isotherms were developed for optimum conditions, and it was seen that the adsorption equilibrium data fit the noncompetitive Freundlich model. For the multicomponent adsorption equilibrium the competitive adsorption isotherms were also developed. The competitive Freundlich model for binary metal mixtures represented most the column adsorption equilibrium data of Cr(VI) and Cu(II) on R. arrhizus satisfactorily.

Keywords: Immobilized Biomass, Heavy-Metals, Adsorption, Equilibria, Removal, Waste Water, Free Microorganism, Simultaneous Biosorption, Chromium(VI), Copper(II), Packed Column, The Competitive Freundlich Model

Huh, J.K., Song, D.I. and Jeon, Y.W. (2000), Sorption of phenol and alkylphenols from aqueous solution onto organically modified montmorillonite and applications of dual-mode sorption model. Separation Science and Technology, 35 (2), 243-259.

Full Text: S\Sep Sci Tec35, 243.pdf

Abstract: Single- and multisolute competitive sorptions were carried out in a batch reactor to investigate the uptake of phenol, 4-methylphenol (MeP), 2,4-dimethylphenol (DMeP), and 4-ethylphenol (EtP) dissolved in water at 25°C onto organically modified montmorillonite. Hexadecyltrimethylammonium (HDTMA) cation was exchanged for metal cations on the montmorillonite to the extent of the cation-exchange capacity (CEC) of the montmorillonite to prepare HDTMA–montmorillonite, changing its surface property from hydrophilic to organophilic. It was observed from the experimental results that the adsorption affinity on HDTMA–montmorillonite was in the order 4-EtP 2,4-dMeP 4-MeP phenol. The Langmuir, dual-mode sorption (DS), and Redlich–Peterson (RP) models were used to analyze the single-solute sorption equilibria. The competitive Langmuir model (CLM), competitive dual-mode sorption model (CDSM), and ideal adsorbed solution theory (IAST), coupled with the single-solute models (i.e., Langmuir, DS, and RP models), were used to predict the multisolute competitive sorption equilibria. All the models considered in this work yielded favorable representations of both single- and multisolute sorption behaviors. DSM, CDSM, and IAST coupled with the DSM were found to be other satisfactory models to describe the single- and multisolute sorption of the phenolic compounds onto HDTMA–montmorillonite.

Keywords: Adsorption, Alkylphenols, Applications, Capacity, Cation, Cation Exchange Capacity, Clay, Dissolved, Distributed Reactivity Model, Equilibrium, Hdtma, Hydrophilic, Ideal, Langmuir, Model, Models, Modified, Montmorillonite, Phenol, Phenolic Compounds, Predict, Reactor, Sediments, Smectite, Soils, Sorption, Surface, Thermodynamics, Uptake, Water

Bae, J.H., Song, D.I. and Jeon, Y.W. (2000), Adsorption of anionic dye and surfactant from water onto organomontmorillonite. Separation Science and Technology, 35 (3), 353-365.

Full Text: S\Sep Sci Tec35, 353.pdf

Abstract: Single-and bisolute competitive adsorptions were carried out to investigate the adsorption behavior of an anionic dye, Orange II, and an anionic surfactant, dodecylbenzenesulfonate (DBS), from water at 25C onto montmorillonite treated with hexadecyltrimethylammonium (HDTMA) cation. The monovalent HDTMA cation was exchanged for the metal cations on the montmorillonite to prepare HDTMA-montmorillonite, changing its surface property from hydrophilic to organophilic. Adsorption affinity of DBS on HDTMA-montmorillonite was found to be slightly higher than that of Orange II, probably due to hydrophobic or nonpolar interactions between the long hydrocarbon chains of the HDTMA with an anion. The single-solute adsorption data were fitted to the Langmuir and the Redlich-Peterson (RP) adsorption models. The competitive Langmuir model and the ideal adsorbed solution theory (IAST) coupled with the single-solute adsorption models were used to predict the bisolute competitive adsorption equilibria. Among the models, the IAST coupled with the Langmuir and the RP models for DBS and Orange II, respectively, yielded the most favorable representation of the bisolute competitive adsorption behavior.

Keywords: Organic Pollutants, Sorption, Chromate, Clinoptilolite, Phenols

Hasany, S.M., Saeed, M.M. and Ahmed, M. (2000), Adsorption isotherms and thermodynamic profile of Co(II)—SCN complex uptake on polyurethane foam. Separation Science and Technology, 35 (3), 379-394.

Full Text: S\Sep Sci Tec35, 379.pdf

Abstract: Sorption of cobalt(II)–thiocyanate complex onto polyurethane foam (PUF) has been investigated in detail with respect to the equilibrating time between Co(II)-thiocyanate complex in solution and foam, and concentrations of cobalt(II) and sorbent. The sorption was optimized with respect to the composition of electrolyte. Maximum sorption has been achieved from 0.1 M HCl solution containing 0.5 M SCN after 10 minutes of shaking time. The kinetics and thermodynamics of sorption are studied in detail. The kinetics follow a first-order rate equation with the rate constant, k, equal to 9.57×10^-2 min.^-1 The variation of equilibrium constant K_c with temperature (15–50°C) yields values of ΔH = -64±4.6 kJ.mol^-1, ΔS = -192.6±15.6 J.mol^-1.K^-1, and ΔG = -8.71 kJ.mol^-1 at 298 K. The sorption of Co(II)-thiocyanate onto PUF in the presence of common anions and cations has also been measured. The sorption data studied in the concentration range of Co(II) 1.12×10^-4 to 1.20×10^-3 M follow Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherms. Freundlich parameters 1/n = 0.35±0.02 and A = 0.85±0.2 mmol.g^-1, Langmuir constants Q = (5.54±0.12)×10^-5 mol.g^-1 and b = (3.55±0.74)×10⁴ dm³.mol^-1 and D–R isotherms β= -0.002999±0.000189 kJ².mol^-2, C_m = 10.66±0.16×10^-4 mol.g^-1 and E = 12.9±0.4 kJ.mol^-1 have been evaluated. The possible sorption mechanism of cobalt–thiocyanate complex onto PUF is also discussed.

Keywords: Adsorption, Adsorption Isotherms, Co(II), Cobalt(II), Composition, Concentration, Data, Equilibrium, Extraction, First Order, Foam, Freundlich, Iridium, Isotherms, Kinetics, Kinetics and Thermodynamics, Langmuir, Mechanism, Polyurethane, Polyurethane Foam, Preconcentration, Rate Constant, Rhodium, Separation, Solution, Sorbent, Sorption, Sorption Mechanism, Temperature, Thermodynamic, Thermodynamics, Thiocyanate, Uptake, Zinc

Bassi, R., Prasher, S.O. and Simpson, B.K. (2000), Removal of selected metal ions from aqueous solutions using chitosan flakes. Separation Science and Technology, 35 (4), 547-560.

Full Text: S\Sep Sci Tec35, 547.pdf

Abstract: Commercially available chitosan’s potential in the adsorption of heavy metals like zinc, copper, cadmium, and lead from aqueous solutions under variable physicochemical conditions was investigated. The results obtained from equilibrium and kinetic studies showed that there was significant uptake of these metal ions by chitosan and that chitosan flakes had a maximum sorption capacity for copper ions. The order of metal ion adsorption by chitosan decreased from Cu²⁺ to Zn²⁺ as follows: copper < lead < cadmium < zinc. There was a considerable increase in sorption capacity with an increase in chitosan amount, however, this parallelism diminished when the chitosan mass exceeded 0.24 g in 25 mL of metalsolution. The sorption of metal ions from various salt solutions by chitosan flakes was not improved by agitation. The heavy metal uptake by chitosan was found to be pH-dependent, with a maximum at pH 6.0 and 7.0. Sorption equilibrium studies were conducted with a constant sorbent weight and varying initial concentration of metal ions. The experimental data of adsorption from solutions containing metal ions were found to correlate well with the Langmuir isotherm equation.

Keywords: Adsorption, Sorption, Beads, Heavy Metals, Chitosan, Adsorption, Kinetics, Equilibrium

? Suen, S.Y., Tsai, Y.H. and Chen, R.L. (2000), Comparison of breakthrough performance using dye-affinity membrane disks and gel bead columns. Separation Science and Technology, 35 (4), 573-591.

Full Text: 2000\Sep Sci Tec35, 573.pdf

Abstract: The breakthrough curve performance of lysozyme and bovine serum albumin to immobilized Cibacron 3GA using different solid supports such as gel beads and membrane disks was investigated in this work. The effects of flow rate and different module designs were also studied. Variation in the flow rate was found to be insignificant for the column process in both nonadsorption and single-protein experiments, but it affected the elution peak height for membrane disks. The peak height decreased with increasing flow rate. As for the effect of different designs, a long column and a wide membrane stack induced a broader breakthrough performance. The performance varied with different solid supports in two-protein experiments. Competitive adsorption occurred for a gel bead column, and the breakthrough curve performance resembled the prediction of combining local equilibrium theory and the extra module effect. The affinity strenth to the gel bead support is in the order lysozyme > BSA dimer > BSA monomer. As for membrane performance, two BSA solutes did not adsorb onto membranes, so as simple separation of lysozyme from BSA, instead of displacement phenomena, was observed.

Keywords: Adsorption, Albumin, Bovine Serum Albumin, Breakthrough, Breakthrough Curve, BSA, Dye-Affinity, Elution, Equilibrium, Flow Rate, Lysozyme, Protein Chromatography, Purification, Separation

Yu, Q.M. and Kaewsarn, P. (2000), Adsorption of Ni²⁺ from aqueous solutions by pretreated biomass of marine macroalga Durvillaea potatorum. Separation Science and Technology,