Personal Research Database

Full Text: 2006\Sep Sci Tec41, 3485.pdf, 2006\Sep Sci Tec-Wen.pdf

Abstract: The adsorption of ammonium ions onto a Chinese natural zeolite in an agitated batch adsorber was studied. A trial-and-error non-linear method was developed to examine two widely used isotherms, the Langmuir and Freundlich. The data gained from the adsorption system fitted the Freundlich isotherm better. An ion exchange model, describing the relationship among the total metal ions in the solution, NH₄t removed from the solution, and ions initially released from the zeolite, was developed for the adsorption system. In addition, a parameter of the ion exchange potential was defined to describe the adsorption mechanism. Ion exchange was the main mechanism that accounted for the adsorption of ammonium ions onto the Chinese natural zeolite.

Keywords: Natural Zeolite, Adsorption, Isotherm, Ion Exchange

? Abu Al-Rub, F.A. (2006), Biosorption of zinc on palm tree leaves: Equilibrium, kinetics, and thermodynamics studies. Separation Science and Technology, 41 (15), 3499-3515.

Full Text: 2006\Sep Sci Tec41, 3499.pdf

Abstract: The efficiency of using palm tree leaves to remove zinc ions from aqueous solution was studied. Adsorption isotherms, kinetics, and thermodynamics studies were conducted. The influence of different experimental parameters, such as equilibrium pH, shaking rate, temperature, and the presence of other pollutants such as chelating agents on the biosorption of zinc on palm tree leaves was investigated.

Batch biosorption experiments showed that palm tree leaves used in this study proved to be suitable for the removal of zinc from dilute solutions where a maximum uptake capacity of 14.7 mg/g was obtained at 25°C. Zinc biosorption on palm tree leaves was found to be highly pH dependent. The biosorption process was found to be rapid with 90% of the adsorption completed in about 10 min. Dynamics studies of the biosorption of zinc on palm tree leaves showed that the biosorption process followed the pseudo second-order kinetics with little intraparticle diffusion mechanism contribution. The equilibrium results indicated that zinc biosorption on palm tree leaves could be described by the Langmuir, Freundlich, Gin et al., and Sips models. Using the Langmuir equilibrium constants obtained at different temperatures, the thermodynamics properties of the biosorption (Delta G(0), Delta H-0, and Delta S-0) were also determined. The values of these parameters indicated the spontaneous and endothermic nature of zinc biosorption on palm tree leaves.

Keywords: Biosorption, Zinc, Palm Tree Leaves, Isotherms, Aqueous-Solution, Heavy-Metals, Chlorella-Vulgaris, Activated Carbon, Lead Ions, Removal, Sorption, Cadmium, Adsorption, Copper

? Özcan, A.S., Özcan, A., Tunali, S., Akar, T., Kiran, I. and Gedikbey, T. (2007), Adsorption potential of lead(II) ions from aqueous solutions onto Capsicum annuum seeds. Separation Science and Technology, 42 (1), 137-151.

Full Text: 2007\Sep Sci Tec42, 137.pdf

Abstract: The purpose of this work was to evaluate the adsorption potential of Capsicum annumn seeds, in a batch system for the removal of lead(H) ions from aqueous solutions. The experimental results showed that this agricultural by-product was effective in removing lead(H) ions. The FT-IR analysis indicated that the mechanism involved in adsorption of lead(H) ions by seeds of C. annuum was mainly attributed to lead(H) binding of amino and hydroxyl groups. Adsorption equilibrium approached within 40 min. The adsorption data fitted well to the Langmuir isotherm model. The maximum adsorption capacity (q_max) was 1.8710^-4 mol g^-1. Pseudo-second-order kinetic model was applicable to all the adsorption data over the entire time range. The thermodynamic parameters indicated that the adsorption process is spontaneous since Gibbs free energy values are negative, which are between -26.92 and -30.77 kJ mol at the temperature range of 20-50°C.

Keywords: Agricultural By-Products, Adsorption, Heavy Metals, Isotherm, Kinetics, Capsicum Annuum Seeds, Heavy-Metals, Removal, Biosorption, Biomass, Equilibrium, Copper(II), Biosorbent, Kinetics, Pb(II), Water

? Liu, Y., Xiao, D. and Li, H. (2007), Kinetics and thermodynamics of lead(II) adsorption on vermiculite. Separation Science and Technology, 42 (1), 185-202.

Full Text: 2007\Sep Sci Tec42, 185.pdf

Abstract: The kinetics and thermodynamics of Pb(II) adsorption on vermiculite have been studied by the sets of experiments at various conditions (temperature, initial lead concentration and adsorption time). The structures of the vermiculite before and after Pb(II) adsorption were measured using X-ray diffraction (XRD), thermogravimetric analysis (TA), and X-ray photoelectron spectroscopy (XPS). Adsorption of Pb(II) was strongly affected by pH. First order kinetics model best described the reaction rate, and the adsorption capacity calculated by the model was consistent with that actual measurement. Isotherms for the adsorption of Pb(II) on vermiculite were developed and the equilibrium data fitted well to the Langmuir and Freundlich models. Thermodynamic parameters such as enthalpy, entropy, and free energy were calculated using the Van’t Hoff equations. The thermodynamics of Pb(II) on vermiculite indicates the spontaneous and endothermic nature of adsorption. Quantitative desorption of Pb(II) from vermiculite was found to be more than 40% which facilitates the sorption of metal by ion exchange.

Keywords: Kinetics, Thermodynamics, Adsorption, Lead, Vermiculite, Bagasse Fly-Ash, Sugar-Industry Waste, Aqueous-Solutions, Activated Carbon, Metal Removal, Water, Cadmium, Ions, Biosorption, Equilibrium

? Torres-Pérez, J., Solache-Ríos, M. and Olguín, M.T. (2007), Sorption of azo dyes onto a Mexican surfactant-modified clinoptilolite-rich tuff. Separation Science and Technology, 42 (2), 299-318.

Full Text: 2007\Sep Sci Tec42, 299.pdf

Abstract: The selectivity of a Mexican surfactant-modified clinoptilolite-rich tuff to retain azo dyes (red-40, yellow-5 and a mixture of them) from aqueous solutions has been investigated. The zeolitic material was modified with hexadecyltrimethylammonium bromide and then left in contact with azo dyes. The uptake was determined at different contact times and concentrations of dyes solutions. First order Elovich, and pseudo second order models as well as the lineal, Langmuir, and Freundlich isotherms were used to describe the experimental data. It was found that in single and binary solutions, under the experimental conditions, the modified zeolitic material retain preferentially the dye red-40 in comparison to yellow-5. The best models to describe the reaction rate and the sorption of azo dyes red-40 and yellow-5 by Mexican surfactant modified clinoptilolite-rich tuff were pseudo-second order and Langmuir models, respectively. These results show that surfactant modified clinoptilolite-rich tuff from Villa de Reyes (San Luis Potosi, Mexico) could be considered as a potential adsorbent of azo dyes from aqueous solutions.

Keywords: Dye, Modified Zeolitic Rock, Sorption, Aqueous-Solutions, Reactive Dyes, Color Removal, Adsorption, Hexadecyltrimethylammonium, Sepiolite, Zeolites, Kinetics, Cadmium

? Jacques, R.A., Bernardi, R., Caovila, M., Lima, E.C., Pavan, F.A., Vaghetti, J.C.P. and Airoldi, C. (2007), Removal of Cu(II), Fe(III), and Cr(III) from aqueous solution by aniline grafted silica gel. Separation Science and Technology, 42 (3), 591-609.

Full Text: 2007\Sep Sci Tec42, 591.pdf

Abstract: The aniline moiety was covalently grafted onto silica gel surface. The modified silica gel with aniline groups (SiAn) was used for removal of Cu(II), Fe(III), and Cr(III) ions from aqueous solution and industrial effluents using a batch adsorption procedure. The maximum adsorption of the transition metal ions took place at pH 4.5. The adsorption kinetics for all the adsorbates fitted better the pseudo second-order kinetic model, obtaining the following adsorption rate constants (k(2)): 1.23310^-2, 1.90210^-2, and 8.32010^-3 g.mg^-1 min^-1 for Cr(III), Cu(II), and Fe(III), respectively. The adsorption of these transition metal ions were fitted to Langmuir, Freundlich, Sips, and Redlich-Peterson isotherm models, however, the best isotherm model fitting which presented a lower difference of the q (amount adsorbed per gram of adsorbent) calculated by the model from the experimentally measured, was achieved by using the Sips model for all adsorbates chosen. The SiAn adsorbent was also employed for the removal of the transition metal ions Cr(III) (95%), Cu(II) (95%), and Fe(III) (94%) from industrial effluents, using the batch adsorption procedure.

Keywords: Adsorbent, Adsorption, Adsorption Kinetics, Adsorption Rate, Aniline, Batch Adsorption Procedure, Biosorption, Chemically Modified Silica Gel, Chitosan, Copper, Effluents, Equilibrium, Freundlich, Gel, Grafted, Groups, Heavy-Metal Removal, Industrial, Industrial Effluents, Ions, Isotherm, Isotherm Models, Kinetic, Kinetic Model, Kinetics, Kinetics of Adsorption, Langmuir, Mesoporous Silicas, Metal, Metal Ions, Model, Models, Modified, Natural-Waters, pH, Pseudo-Second-Order, Removal, Silica, Silica Gel, Sorbent, Surface, Transition Metal, Treatment of Effluents

? Chuang, Y.H., Ju, Y.H. and Widjaja, A. (2007), Kinetic studies of phytosterol adsorption on zeolite. Separation Science and Technology, 42 (3), 611-624.

Full Text: 2007\Sep Sci Tec42, 611.pdf

Abstract: Equilibrium isotherms of sterol adsorption on zeolite show the characteristics of irreversible equilibrium adsorption. First order and second order surface adsorption control mechanisms as well as micropore diffusion control model failed to satisfactorily describe the kinetics of sterol adsorption on zeolite. From the analysis of adsorption data, it was found that macropore diffusion control model satisfactorily describes the kinetics of sterol adsorption on zeolite. The effect of temperature on the diffusivity during adsorption was found to conform to the Eyring equation. It was shown that a change in temperature has a negligible effect on the selectivity of sterol adsorption on zeolite.

Keywords: Adsorption, Analysis, Beta-Sitosterol, Beta-Sitosterol, Campesterol, Control, Diffusion, Equilibrium, Isotherms, Kinetic Model, Kinetics, Mechanisms, Model, Purification, Selectivity, Separation, Speed Countercurrent Chromatography, Sterol, Surface, Temperature, Zeolite

? Ghazy, S.E. and Ragab, A.H. (2007), Removal of lead from water samples by sorption onto powdered limestone. Separation Science and Technology, 42 (3), 653-667.

Full Text: 2007\Sep Sci Tec42, 653.pdf

Abstract: Bench scale batch adsorption experiments were performed, aiming at the removal of the Pb²⁺ ions from aqueous solutions and water samples by fine powdered Limestone (LS) as an effective inorganic sorbent, which is inexpensive, widespread, and cheap. The main parameters (i.e., solution pH, sorbent and lead concentrations, stirring times, and temperature) influencing the sorption process, in addition to the effect of some foreign ions, were investigated. The results obtained stated that the sorption of Pb²⁺ ions onto LS is well described by Freundlich model and deviated from that of Langmuir over the concentration range studied. Under the optimum experimental conditions employed, the removal of ca. 100% of Pb²⁺ ions was attained. The procedure was successfully applied to the removal of lead from aqueous and different natural water samples. Moreover, the adsorption mechanism is suggested.

Keywords: Lead, Sorption, Powdered Limestone, Natural Waters, Heavy-Metal Removal, Aqueous-Solutions, Adsorption, Calcite, Ions, Effluents, Wastes, Hydroxyapatite, Adsorbents, Retention

Full Text: 2007\Sep Sci Tec42, 653.pdf

? Deliyanni, E.A., Peleka, E.N. and Matis, K.A. (2007), Effect of cationic surfactant on the adsorption of arsenites onto akaganeite nanocrystals. Separation Science and Technology, 42 (5), 993-1012.

Full Text: 2007\Sep Sci Tec42, 993.pdf

Abstract: The current research focuses on removal of arsenite ions from aqueous solutions by a new adsorbent, surfactant modified akaganeite (Ak(m)), prepared after the adsorption of the cationic surfactant, hexadecyl trimethyl ammonium bromide (N-Cetyl-N,N,N-Trimethylammonium Bromide) onto akaganeite. The new adsorbent was investigated with Fourier transform infrared spectra and X-ray photoelectron spectroscopy methods for a better understanding of the effects of surface properties on arsenite adsorption. Surfactant modified akaganeite was found to be an effective adsorbent for the removal of arsenite ions from aqueous systems. It presented a significantly higher arsenite adsorption capacity than the pure nanocrystalline akaganeite. Kinetics of adsorption obeys a second-order rate equation. The maximum adsorption capacity was found to 328.3 mg g^-1 over a wide pH range significantly higher than those of other adsorbents reported.

Keywords: Activated Alumina, Adsorbent, Adsorbents, Adsorption, Adsorption Capacity, Akaganeite, Ammonium, Aqueous-Solutions, Arsenate, Arsenite, Arsenite Removal, Biosorption, Capacity, Cationic Surfactant, Effects, Equilibrium, Iron Oxide Hydroxide, Mechanisms, Methods, Modified, Modified Clinoptilolite, Nanocrystalline, pH, Photoelectron Spectroscopy, Process Mechanism, Properties, Range, Rate Equation, Removal, Research, Spectroscopy, Surface, Surface Properties, Surfactant, Surfactant-Modified Adsorbent, Titanium-Dioxide, X-Ray Photoelectron Spectroscopy

? Yilmaz, I., Kabay, N., Yuksel, M., Holdich, R. and Bryjak, M. (2007), Effect of ionic strength of solution on boron mass transfer by ion exchange separation. Separation Science and Technology, 42 (5), 1013-1029.

Full Text: 2007\Sep Sci Tec42, 1013.pdf

Abstract: In the present study, batch kinetic tests have been performed for boron removal from model solutions using boron selective ion exchange resins Diaion CRB 02, Dowex (XUS 43594.00) and Purolite S 108. Several kinetic models have been used to evaluate the sorption kinetics of boron by means of a well mixed stirred system, diffusional models, pseudo-first-order, and pseudo-second-order kinetic models. The mass transfer model, based on a well stirred system including maximum capacity (Q(m), mg/g) and Langmuir constant (b, L/mg) values obtained from Langmuir isotherms, has been used to obtain predictive concentration changes against time. The experimental results have been used to compare with the modelling data for different ionic strength media.

Keywords: Boron, Capacity, Concentration, Geothermal Waste-Water, Ion, Ion Exchange, Ion-Exchange, Ionic Strength, Isotherms, Kinetic, Kinetic Models, Kinetics, Langmuir, Langmuir Isotherms, Mass Transfer, Media, Model, Modelling, Models, Power-Plant, Pseudo Second Order, Pseudo-Second-Order, Recovery, Removal, Resins, Selective, Separation, Sorption, Sorption Kinetics, Sorption-Elution, Strength, Tests, Transfer, Water

? Wang, X.S., Hu, H.Q. and Sun, C. (2007), Removal of copper(II) ions from aqueous solutions using Na-mordenite. Separation Science and Technology, 42 (6), 1215-1230.

Full Text: 2007\Sep Sci Tec42, 1215.pdf

Abstract: The potential to remove copper(II) ions from aqueous solutions using Na-mordenite, a common zeolite mineral, was thoroughly investigated. The effects of relevant parameters solution pH, adsorbent dose, ionic strength, and temperature on copper(II) adsorption capacity were examined. The sorption data followed the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherms. The maximum sorption capacity was found to be 10.69 mg/g at pH 6, initial concentration of 40 mg/dm³, and temperature of 40°C. Different thermodynamic parameters viz., changes in standard free energy (G°), enthalry (H°), and entropy (S°) have also been evaluated and the results show that the sorption process was spontaneous and endothermic in nature. The dynamics of the sorption process were studied and the values of rate constant of adsorption, rate constant of intraparticle diffusion were calculated. The activation energy (E-a) was found to be 11.25 kJ/mol in the present study, indicating a chemical sorption process involving weak interactions between sorbent and sorbate. The interaction between copper(II) ions and Na-mordenite is mainly attributable to ion exchange. The sorption capacity increased with the increase of solution pH and the decrease of ionic strength and adsorbent dose. The Na-mordenite can be used to separate copper(II) ions from aqueous solutions.

Keywords: Adsorption, Copper(II), Na-Mordenite, Sorption Mechanism, Wastewater Treatment, Sorption Isotherms, Activated Carbon, Waste-Water, Tree Fern, Adsorption, Equilibrium, Zeolites, Biosorbents, Kinetics, Sawdust

? Bhatnagar, A., Minocha, A.K., Jeon, B.H. and Park, J.M. (2007), Adsorptive removal of cobalt from aqueous solutions by utilizing industrial waste and its cement fixation. Separation Science and Technology, 42 (6), 1255-1266.

Full Text: 2007\Sep Sci Tec42, 1255.pdf

Abstract: In the present study, the adsorption potential of battery industry waste as adsorbent has been investigated for the removal of cobalt from aqueous solutions. The results have shown that the prepared adsorbent adsorbs cobalt to a sufficient extent (35 mg/g). The adsorption of cobalt has been studied on this battery industry waste as a function of contact time, concentration, and temperature by the batch method. The adsorption has been found to be endothermic and the data conform to the Langmuir equation. The analysis of kinetic data indicates that adsorption is a first order process and pore-diffusion controlled.

Further, the metal-laden adsorbent was immobilized into cement for ultimate disposal and no significant leaching was observed from the stabilized products. Thus, the present study clearly reveals that battery industry waste can be fruitfully employed in treating industrial effluents containing toxic metal ions.

The proposed technology (utilization of industrial wastes for effluent treatment and then ultimate disposal of adsorbents laden with pollutants in cementitious materials by fixation) provides a twofold aim of wastewater treatment and solid waste management.

Keywords: Industrial Waste Minimization, Battery Industry Waste, Adsorbent, Cobalt Removal, Water Treatment, Blast-Furnace Sludge, Sorption, Adsorbent, Kinetics, Water, Lead(II), Models, Ions, Peat, Slag

? Jain, S. and Jayaram, R.V. (2007), Adsorption of phenol and substituted chlorophenols from aqueous solution by activated carbon prepared from jackfruit (artocarpus heterophyllus) peel-kinetics and equilibrium studies. Separation Science and Technology, 42 (9), 2019-2032.

Full Text: 2007\Sep Sci Tec42, 2019.pdf

Abstract: This study is aimed at the effectiveness of an adsorbent prepared from jackfruit peel (artocarpus heterophyllus), an agricultural waste, for the removal of phenol, 2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol from aqueous solutions. Batch adsorption experiments were carried out as a function of solution pH, contact time, phenol concentration, adsorbent dose, and temperature. The adsorption equilibrium was reached in 5 h. The order of removal was found to be 2,4-dichlorophenol > 4-chlorophenol > 2-chlorophenol > phenol. The Freundlich and Langmuir isotherm models were applied to the equilibrium data. The maximum sorption capacities for phenol, 2-chlorophenol, 4-chlorophenol, and 2,4-dichlorophenol were found to be 144.9 mg/g, 243.9 mg/g, 277.7 mg/g, and 400.0 mg/g respectively. The removal of phenols was found to be most effective at lower pH. Kinetic data of the adsorption process could fit a pseudo second order rate equation. An attempt was also made to understand the mechanism of phenol adsorption. The results reveal that the activated carbon prepared can be economical for the removal of phenols compared to many other reported adsorbents.

Keywords: 2,4-Dichlorophenol, 2-Chlorophenol, 4-Chlorophenol, Activated Carbon, Adsorbent, Adsorbents, Adsorption, Adsorption Equilibrium, Adsorption Isotherm, Adsorption Process, Agricultural, Agricultural Solid-Waste, Agricultural Waste, Aqueous Solution, Aqueous Solutions, Carbon, Carbon Black, Chlorophenols, Coir Pith, Concentration, Contact Time, Dyes, Effective, Effectiveness, Equilibrium, Equilibrium Data, Equilibrium Studies, Freundlich, Function, Isotherm, Isotherm Models, Jackfruit Peel, Langmuir, Langmuir Isotherm, Langmuir-Isotherm, Made, Mass-Transfer, Maximum Sorption, Mechanism, Models, Order, Oxidation, pH, Phenol, Phenol Adsorption, Phenols, Process, Pseudo Second Order, Pseudo-Second-Order, Rate, Rate Equation, Removal, Removal of Phenol, Second Order, Shell, Solution pH, Solutions, Sorption, Surface-Chemistry, Temperature, Waste

? Zhao, Y.Q., Razali, M., Babatunde, A.O., Yang, Y. and Bruen, M. (2007), Reuse of aluminum-based water treatment sludge to immobilize a wide range of phosphorus contamination: Equilibrium study with different isotherm models. Separation Science and Technology, 42 (12), 2705-2721.

Full Text: 2007\Sep Sci Tec42, 2705.pdf

Abstract: The adsorption equilibrium of a wide range of phosphorus species by an aluminum-based water treatment sludge (Al-WTS) was examined in this study. Four kinds of adsorption-isotherm models, namely Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich, were used to fit the adsorption equilibrium data. In order to optimize the adsorption-isotherm model, correlation coefficient (R-2) and four error functions were employed to facilitate the evaluation of fitting accuracy. Experiments have demonstrated that the Al-WTS may be an excellent raw material to adsorb P in a polluted aqueous environment with adsorption ability in the order of KH₂PO₄ (orthoP) > Na(PO₃)₆ (poly-P) > C₁₀H₁₄N₅O₇P center dot H₂O (organic-P). More importantly, this study provides an entire comparison of the four isotherms in describing the P adsorption behavior. By considering both the standard least-square based R-2 and the results of four error functions analysis, this study reveals that the Freundlich isotherm appears to be the best model to fit the experimental equilibrium data. Langmuir and Temkin isotherms are also good models in current experimental conditions while the Dubinin-Radushkevich isotherm poorly described the adsorption behavior. The error analysis in this study provides vital evidence to reflect its role in facilitating the optimization in the adsorption isotherm study. Obviously, R-2 seems inadequate in optimizing multi-isotherm models due to its inherent bias resulting from the least-squares linearization.

Keywords: Adsorption, Aluminum, Disposal, Drinking Water Treatment Sludge, Phosphorus Removal, Reuse, Wastewater Treatment, Treatment Residuals, Waste-Water, Reduce Phosphorus, Removal, Adsorption, Sorption, Wastewaters, Mechanisms, Retention, Capacity

? Yousef, R.I. and El-Eswed, B. (2007), Adsorption behavior of chlorophenols on natural zeolite. Separation Science and Technology, 42 (14), 3187-3197.

Full Text: 2007\Sep Sci Tec42, 3187.pdf

Abstract: The adsorption of aqueous organic pollutants, i.e., phenol, monochlorophenols (2- and 4-), and dichlorophenols (2,4- and 3,5-) on natural Jordanian zeolitic tuff was studied. Three simplified kinetic models, viz., pseudo-first order, pseudo-second order, and intraparticle diffusion models were used to fit the kinetics data. The results revealed that at earlier stages of adsorption of phenols onto zeolite, the pseudo-second order and the bulk diffusion rate constants are dependent on the acidity and the hydrophobicity of phenols. Whereas at later stages of adsorption, the adsorption capacity and the intraparticle diffusion rate constants are affected by the molecular size and the extent of dissociation of phenols.

Keywords: Acidity, Adsorption, Adsorption Capacity, Aqueous-Solutions, Basic-Dyes, Behavior, Capacity, Chlorophenols, Constants, Diffusion, Diffusion Models, Diffusion Rate, Dissociation, Hydrophobicity, Intraparticle, Intraparticle Diffusion, Ions, Kinetic, Kinetic Models, Kinetic-Models, Kinetics, Models, Monochlorophenols, Natural, Natural Zeolite, Order, Organic, Organic Pollutants, Peat, Phenol, Phenol, Phenols, Pollutants, Pseudo Second Order, Pseudo-First and, Pseudo-First Order, Pseudo-First-Order, Pseudo-Second Order, Pseudo-Second-Order, Rate, Rate Constants, Size, Sorption, Zeolite, Zeolitic Tuff

? Cotoruelo, L.M., Marqués, M.D., Díaz, F.J., Rodríguez-Mirasol, J., Cordero, T. and Rodríguez, J.J. (2007), Activated carbons from lignin: Their application in liquid phase adsorption. Separation Science and Technology,