Personal Research Database

Full Text: 2005\Sep Pur Tec45, 79.pdf

Abstract: The sorption of Cd(II) and Pb(II) from aqueous solutions by a low-cost sorbent (leonardite) was investigated. The effect of pH, contact time and initial metal concentration was studied. The sorption of the two metals was pH dependant, the optimum range being 5–6. Batch kinetic studies showed that equilibrium was reached after 2 h. The sorption data were correlated with the Langmuir and Freundlich adsorption models. The maximum adsorption capacities obtained from the Langmuir isotherms were 0.45 mmol g⁻¹ (50.6 mg g⁻¹) and 1.21 mmol g⁻¹ (250.7 mg g⁻¹) for Cd(II) and Pb(II), respectively.

An extensive study of the competitive adsorption between both metals was performed under the same conditions of the individual experiments. The extended Langmuir model was used to fit the experimental data to a series of 3D response surfaces. For binary systems, the maximum adsorption capacities of Cd(II) and Pb(II) were calculated as 0.27 mmol g⁻¹ (30.6 mg g⁻¹) and 0.57 mmol g⁻¹ (118.7 mg g⁻¹), respectively. Cd(II) adsorption was found to be more sensitive than Pb(II) to the presence of a competitive sorbate.

Keywords: Adsorption, Leonardite, Cadmium, Lead

? Otero, M., Zabkova, M. and Rodrigues, A.E. (2005), Comparative study of the adsorption of phenol and salicylic acid from aqueous solution onto nonionic polymeric resins. Separation and Purification Technology, 45 (2), 86-95.

Full Text: 2005\Sep Pur Tec45, 86.pdf

Abstract: Phenolic compounds are undesirable pollutants in the environment, specifically in aquatic media. Salicylic acid is a phenolic compound, and, together with phenol, which is its precursor, it is present in wastewaters from different industries. Adsorption being one of the most common ways for these wastewaters treatment, the comparison of the adsorption on these compounds onto two different polymeric resins (Amberlite XAD16 and Duolite S861) was the aim of this work. The adsorptive behavior of these resins has been compared in batch and fixed bed operation. Langmuir isotherm model was used to fit equilibrium data. In order to ascertain the fixed bed implementation of the adsorbents, adsorption runs were carried out at laboratory scale and the effects of temperature and flow-rate were addressed. For modelling, the adsorption kinetics a linear driving force (LDF) approximation was used. The LDF rate constant accounting for macropore diffusion and adsorption and the film mass transfer resistance were grouped in an overall mass transfer coefficient. According to the results, the capacity of Duolite S861 for phenol adsorption (96.13 mg g⁻¹) was slightly higher than for Amberlite XAD (81.68 mg g⁻¹). On the contrary, Amberlite XAD salicylic acid adsorptive capacity (85.06 mg g⁻¹) was nearly double than that of Duolite S861 (43.01 mg g⁻¹). From a kinetic point of view, for both the resins the overall mass transfer coefficient was higher when adsorbing phenol than salicylic acid. Nevertheless, in the temperature range studied (293–333 K), the separation parameter for thermal parametric pumping purification is larger for Amberlite XAD16 for both phenol and salicylic acid.

Keywords: Phenol, Salicylic Acid, Polymeric Resins, Adsorptive Purification, Fixed Bed Adsorption

? Deliyanni, E.A. and Matis, K.A. (2005), Sorption of Cd ions onto akaganéite-type nanocrystals. Separation and Purification Technology, 45 (2), 96-102.

Full Text: 2005\Sep Pur Tec45, 96.pdf

Abstract: The aim of this paper is to remove cadmium ions from aqueous solutions by sorption onto synthetic akaganéite-type nanocrystals. This material was shown to be a promising inorganic adsorbent due to its favourite characteristics. Synthetic akaganéite was prepared in the laboratory according to a new method. In this paper, the effects of adsorbent amount, initial cadmium concentration, pH value of solution, concentration of background electrolyte ions and temperature variation on the treatment process of cadmium removal by akaganéite were investigated. Typical adsorption isotherms (Freundlich and Langmuir) were determined for the mechanism of sorption process. X-ray photoelectron spectroscopy (XPS) analysis also revealed useful information.

Keywords: Cadmium Removal, Metal Cations, Adsorbent, Iron Oxides, Industrial Wastewater, Effluents

? Deliyanni, E.A. and Matis, K.A. (2005), Kinetic and equilibrium modelling of lead(II) sorption from water and wastewater by polymerized banana stem in a batch reactor. Separation and Purification Technology, 45 (2), 131-140.

Full Text: 2005\Sep Pur Tec45, 131.pdf

Abstract: The aim of this research work was a kinetic and equilibrium study of the sorption of lead(II) ions from water and wastewater by formaldehyde polymerized banana stem containing sulphonic acid groups. The adsorbent was characterized using surface area analyzer, infrared spectroscopy and scanning electron microscopy measurements. The surface charge and the acid groups of the adsorbent were determined using potentiometric and acid–base titrations, respectively. Batch experiments were performed under kinetic and equilibrium conditions. The optimum pH range for the maximum removal of lead(II) was 5–9. The maximum adsorption of 98.5 and 89.9% took place for an initial concentration of 10 and 25 mg/l, respectively, at pH 6.0. The sorption process occurred in two stages: external mass transport occurred in the early stage and intraparticular diffusion occurred in the long-term stage. The diffusion coefficients, energies of activation and entropies of activation for both processes were calculated to determine the theoretical behaviour of the sorption process. In the external mass transfer process, the diffusion coefficient increases with increasing initial concentration while in the intraparticle diffusion process, the diffusion coefficient decreases with increasing initial concentration. The temperature dependence indicates the endothermic nature of adsorption process. The Langmuir, Freundlich and Redlich–Peterson isotherm models were tried to represent the equilibrium data of lead(II) adsorption. The data fitted very well to the Freundlich isotherm model in the studied concentration range of lead(II) adsorption. Quantitative removal of 10.0 mg/l lead(II) in 50 ml of battery manufacturing wastewater by 125 mg of the adsorbent was observed at pH 6.0. The adsorbent was suitable for repeated use (for more than four cycles) without noticeable loss of capacity.

Keywords: Adsorption, Lead(II) Removal, Polymerized Banana Stem, Kinetics, Mass Transport, Isotherm Constants

? Raman, G., Jayaprakasha, G.K., Cho, M., Brodbelt, J. and Patil, B.S. (2005), Rapid adsorptive separation of citrus polymethoxylated flavones in non-aqueous conditions. Separation and Purification Technology, 45 (2), 147-152.

Full Text: 2005\Sep Pur Tec45, 147.pdf

Abstract: Flavanoids exist as secondary plant metabolites, which displays a wide variety of biological effects. The polymethoxylated flavones, such as nobiletin and tangeretin, present in Citrus reticulata peels are of great interest due to their pharmacological effects. Separation and isolation of these structurally very similar flavones has been achieved by using commercially available ion exchange resins. The strong cation exchange resin [H⁺] selectively adsorbs the tangeretin and other phenolic compounds present in the matrix in comparison to the hexamethoxylated flavone, i.e. nobiletin. The cation exchange resin can be used successfully to isolate nobiletin and tangeretin from a plant extract. Purity of the isolated compounds was monitored by HPLC using a C-18 column with photometric detection at 280 nm. The structures of the isolated compounds have been confirmed by NMR and tandem mass spectrometry.

Keywords: Citrus, Adsorptive Separation, Polymethoxylated Flavones

? Ho, Y.S., Harouna-Oumarou, H.A., Fauduet, H. and Porte, C. (2005), Kinetics and model building of leaching of water-soluble compounds of Tilia sapwood. Separation and Purification Technology, 45 (3), 169-173.

Full Text: 2005\Sep Pur Tec45, 169.pdf S\Sep Pur Tec-Ho.pdf

Abstract: The kinetics of the leaching of water-soluble compounds of Tilia sapwood was investigated. A batch leaching model, based on the assumption of a second-order mechanism for the leaching, was developed to predict the rate constant of leaching, the saturated leaching capacity, and the initial leaching rate with various leaching temperatures. The rate constant is a function of the temperature, and the leaching of water-soluble compounds of Tilia sapwood is an endothermic process. In addition, the activation energy of leaching was also determined based on the second-order rate constants of the leaching.

Keywords: Kinetics, Second-Order, Leaching, Tilia Sapwood, Extraction, Wood

? Kim, S.I., Aida, T. and Niiyama, H. (2005), Binary adsorption of very low concentration ethylene and water vapor on mordenites and desorption by microwave heating. Separation and Purification Technology, 45 (3), 174-182.

Full Text: 2005\Sep Pur Tec45, 174.pdf

Abstract: Microwave heating can be applied to regeneration of an adsorbent in the removal of volatile organic compounds in very low concentration. In this study, binary adsorption of ethylene and water vapor on mordenites (MORs) was carried out for very low concentration of ethylene. Microwave was irradiated to the adsorbent bed and the effect of adsorbed water on the heating of MORs and the desorption of the adsorbates were investigated. In the binary adsorption, all MORs showed linear adsorption for ethylene in very low concentration range and the amounts of adsorbed ethylene decreased as compared with the adsorption of the single component. NaMOR was heated up rapidly and to high temperature by microwave irradiation under both dry and humid conditions as compared with HMORs. Due to the strong adsorption of water on NaMOR, the coexisting water vapor hindered the adsorption of ethylene, but promoted microwave heating. In microwave heating of NaMOR after pre-adsorption of ethylene and water, ethylene was concentrated maximally about nine times as high as that in initial feed.

Keywords: Binary Adsorption, Regeneration by Microwave Heating, Very Low Concentration Ethylene, Mordenite, Hydrophilic And Hydrophobic

? Bayramoğlu, G. and Arıca, M.Y. (2005), Ethylenediamine grafted poly(glycidylmethacrylate-co-methylmethacrylate) adsorbent for removal of chromate anions. Separation and Purification Technology, 45 (3), 192-199.

Full Text: 2005\Sep Pur Tec45, 192.pdf

Abstract: The removal of chromate anions (CrO₄²⁻) from aqueous solutions under different experimental conditions using cross-linked poly(glycidylmethacrylate-co-methylmethacrylate), poly(GMA-co-MMA), adsorbent was investigated in this study. The epoxy group containing adsorbent in the beads form was prepared from glycidylmethacrylate and methylmethacrylate via suspension polymerization. The epoxy groups of the poly(GMA-co-MMA) beads were used for grafting with ethylenediamine to prepare specific adsorbent (poly(GMA-co-MMA)-ED) for CrO₄²⁻ anions removal from aqueous solutions. Adsorption equilibrium was achieved in approximately 120 min. The removal was favored at low pH, with a maximum adsorption at pH 2.0. Isotherm studies showed that CrO₄²⁻ anions could be effectively removed by poly(GMA-co-MMA)-ED beads. The maximum adsorption capacities of the poly(GMA-co-MMA) and poly(GMA-co-MMA)-ED beads were 0.044 and 0.441 mmol CrO₄²⁻ anions/g of dry adsorbents, respectively. The experimental data of the adsorption equilibrium from CrO₄²⁻ anions aqueous solution correlated well with the Langmuir–Freundlich isotherm model. The experimental data were analyzed using the first- and the second-order kinetic models. The rate constants of adsorption for both kinetics models have been calculated. The second-order model provides the best correlation of the data. Desorption experiments show that the process of adsorption of CrO₄²⁻ anions was reversible and the adsorbent was easily regenerated with 0.1 M NaOH up to 96% recovery.

Keywords: Beads, Adsorption, Heavy Metal Removal, CrO₄^2- Anions, Kinetic Characterization

? Ribeiro, M.H.L. and Ribeiro, I.A.C. (2005), Recovery of erythromycin from fermentation broth by adsorption onto neutral and ion-exchange resins. Separation and Purification Technology, 45 (3), 232-239.

Full Text: 2005\Sep Pur Tec45, 232.pdf

Abstract: Erythromycin was produced by Saccharopolyspora erythraea in batch mode. Selective adsorption was the method chosen to enable the recovery of erythromycin from growth media. The following sorbents were used: neutral resins (XAD-4, XAD-7 and XAD-16) and ion-exchange resins, Amberlite™ IRA-410 (anionic resin) and Amberlite™ IR-120 (cationic resin). A mathematical kinetic model for the adsorption of erythromycin, from fermentation media, versus time, on these resins was used.

The maximum erythromycin adsorption from fermentation media, at 303 K, was attained with XAD-16 (0.38 mmol/g), IR-120 (0.35 mmol/g) and XAD-7 (0.28 mmol/g) resins and a removal higher than 70% (m/v) was achieved with low sorbent loads (less than 1%, m/v). In addition, XAD-7 resin showed a better performance when it was considered the adsorption per unit of surface area (1.22×10⁻³ mmol/m²).

For every solute/sorbent system tested, adsorption equilibrium was attained in less than 3 h contact. The adsorption data for the sorbents XAD-16 and IRA-120 resins are correlated with Freundlich and Langmuir models.

The thermodynamic parameters such as ΔHads, ΔSads and ΔGads were calculated to predict the nature of adsorption. The positive value of enthalpy (6 kJ/mol) suggest that the original salt in the resin is bound strongly, while the positive value of entropy (54 J/mol K) means that liberation of the salt into the solution is entropically favorable, and the favorable entropy drives the overall process, with a free energy of adsorption of −10 kJ/mol.

Keywords: Erythromycin, Fermentation, Saccharopolyspora Erythraea, Adsorption, Neutral Resins, Ion-Exchange Resins

? Adam, O., Bitschené, M., Torri, G., De Giorgi, F., Badot, P.M. and Crini, G. (2005), Studies on adsorption of propiconazole on modified carbons. Separation and Purification Technology, 46 (1-2), 11-18.

Full Text: 2005\Sep Pur Tec46, 11.pdf

Abstract: The adsorption capacity and kinetics of propiconazole in aqueous solution using untreated and treated activated carbons as adsorbents have been studied, providing new experimental data at different temperatures which were obtained using the bottle-point method. Untreated carbon was oxidized with HNO₃, H₂O₂, NaOCl and NaOH to produce a series of samples with different surface chemical properties. The surface chemistry was characterized by the determination of the point of zero charge. It was found that the physical morphology of the sample is affected by the strength of the oxidizing agent and the operating conditions. The surface chemistry of the activated carbon plays a key role in pollutant adsorption performance. Results of sorption experiments showed that carbon modified with NaOH is the best material for the adsorption of propiconazole at pH 6.5. Sorption of propiconazole reached equilibrium in 120 min. The maximum adsorption onto untreated activated carbon was 101 mg/g. As expected, the adsorption increased with increasing temperature. Adsorption kinetics obeyed a second-order kinetic model.

Keywords: Activated Carbon, Activated Carbon, Adsorbents, Adsorption, Adsorption Capacity, Aqueous-Solution, Aromatics, Capacity, Carbon, Chemical, Chemical Properties, Determination, Dye, Equilibrium, Functional-Groups, H₂O₂, Heavy-Metals, HNO₃, Key, Kinetic, Kinetic Model, Kinetics, Low-Cost Adsorbents, Model, Modified, Morphology, Oxidizing, P-Nitrophenol, Performance, pH, Pollutant, Properties, Propiconazole, Sorption, Surface, Surface Chemistry, Surface-Chemistry, Temperature, Waste-Water Treatment, Zero Charge

? Machida, M., Yamazaki, R., Aikawa, M. and Tatsumoto, H. (2005), Role of minerals in carbonaceous adsorbents for removal of Pb(II) ions from aqueous solution. Separation and Purification Technology, 46 (1-2), 88-94.

Full Text: 2005\Sep Pur Tec46, 88.pdf

Abstract: Adsorptive removal of Pb(II) ions from aqueous solution onto a non-activated charcoal (CC) of oak wood origin was studied in comparison with an activated carbon of coal origin. The adsorption capacity for Pb(II) of the non-activated charcoal increased significantly with deceasing particle diameter, whereas the activated carbon (AC) exhibited approximately constant capacity for Pb(II) adsorption as a function of particle size. Adsorption to the ashes prepared from the non-activated charcoal and the activated carbon was also investigated to examine the role of mineral ash. Although the ash from the activated carbon did not show any Pb(II) adsorption, the ash from the charcoal was very effective for Pb(II) adsorption. Furthermore, Pb(II) was hardly adsorbed when the ash was removed from the non-activated charcoal by acid treatment. Based on the results, the adsorption sites for Pb(II) are considered to be acidic surface functional groups on the external and internal surfaces for the activated carbon, mineral ash containing oxides of manganese and magnesium exposed on the external surface are dominantly responsible for the Pb(II) adsorption for the non-activated charcoal.

Keywords: Heavy Metal Ions, Charcoal, Activated Carbon, Ash, Adsorption

? Purakayastha, P.D., Pal, A. and Bandyopadhyay, M. (2005), Sorption kinetics of anionic surfactant on to waste tire rubber granules. Separation and Purification Technology, 46 (3), 129-135.

Full Text: 2005\Sep Pur Tec46, 129.pdf

Abstract: The efficiency of a locally available very low cost waste tire rubber granule in removing anionic surfactant (AS) by adsorption process was evaluated. As a representative member of AS sodium dodecyl sulfate (abbreviated as SDS) was used. It was found that in the batch experiment conducted at 2.0 mg/l initial concentration of SDS, rubber granules could remove up to 92% of SDS from wastewater. Kinetic profiles under various conditions were developed. The equilibrium time was found to be 6 h. Reaction rate constants (forward, reverse and overall) were determined for different initial concentrations of SDS by approximating the kinetic data to the first-order reversible kinetic model. Pore and film diffusion coefficients were determined from the half-time equations and film diffusion appeared to be rate limiting. This was further supported by multiple interruption tests.

Keywords: Adsorption, Anionic Surfactant, Kinetic Studies, Diffusion Coefficient, Rate-Limiting Process

? Sprynskyy, M., Lebedynets, M., Zbytniewski, R., Namieśnik, J. and Buszewski, B. (2005), Ammonium removal from aqueous solution by natural zeolite, Transcarpathian mordenite, kinetics, equilibrium and column tests. Separation and Purification Technology, 46 (3), 155-160.

Full Text: 2005\Sep Pur Tec46, 155.pdf

Abstract: The scope of this study was ammonium ions removal from synthetic aqueous solutions by raw and pretreated natural zeolite, Transcarpathian mordenite under static and dynamic conditions. The cation exchange capacity of the Transcarpathian mordenite regarding ammonium ions was evaluated as 1.64 meq/g at 1000 mg/l initial NH₄–N concentration. The dynamic exchange capacity exceeded one estimated in equilibrium study at the same initial concentration that may be conditioned by the constant removal of ion exchange products. Ammonium uptake rate was controlled by particle diffusion with diffusion coefficients determined in the range of 0.7–3.6×10⁻¹² m²/s. Efficiency of ammonium sorption may be improved by slowing down of initial solution rate in the column test and non-significantly by NaCl and HCl pretreatment of the mordenite. Ammonium sorption by the mordenite increased from the coarser to the finer fraction but this dependence became weaker to low flow rates. It was established that hydrogen ions displaced exchangeable cations on the mordenite in distilled water and hydrochloric acid with destroy of the zeolite framework structure in the last case. NH₄⁺-ions removal from aqueous solutions occurs mainly by ion exchange with Na⁺- and Ca²⁺-ions at the practically equal parts of them because of the weakest affinity of the mordenite to these cations.

Keywords: Mordenite, Ion Exchange, Ammonium Removal, Kinetic and Column Tests

? Yang, W.B., Li, A.M., Zhang, Q.X., Fei, Z.H. and Liu, F.Q. (2005), Adsorption of 5-sodiosulfoisophthalic acids from aqueous solutions onto acrylic ester polymer YWB-7 resin. Separation and Purification Technology, 46 (3), 161-167.

Full Text: 2005\Sep Pur Tec46, 161.pdf

Abstract: A new acrylic ester polymer YWB-7 resin was prepared and systematically characterized. The adsorption properties of YWB-7 resin were compared with those of the commercial Amberlite XAD-7, Diaion HP2MG and hypercrosslinked polymer NDA-150 resins. Both surface area and micropore area of YWB-7 resin are larger than those of XAD-7 and HP2MG resins. The Freundlich isotherm equation was successfully employed to describe the adsorption phenomena. The adsorption experiments showed that the NDA-150 resin has the largest adsorption capacity to 5-sodiosulfoisophthalic acid sodium salt (SIPA) from aqueous solutions without methanol, but the adsorption capacity decreases significantly in SIPA solutions with methanol (5%). In contrast, methanol in SIPA solution has little effect on the adsorption capacity of acrylic ester resins. The adsorption capacities of SIPA on YWB-7 resin in the tested range are always larger than those on XAD-7 and HP2MG resins. Hydrogen bonding is believed to be the predominant interaction between acrylic ester resin and SIPA in the adsorption process and the increasing acid concentration impels the formation of hydrogen bonding to some extent.

Keywords: Acrylic Ester Resin, 5-Sodiosulfoisophthalic Acid Sodium Salt (SIPA), Hydrogen Bonding, Hydrophobic Interaction, Adsorption

? Inglezakis, V.J., Zorpas, A.A., Loizidou, M.D. and Grigoropoulou, H.P. (2005), The effect of competitive cations and anions on ion exchange of heavy metals. Separation and Purification Technology, 46 (3), 202-207.

Full Text: 2005\Sep Pur Tec46, 202.pdf

Abstract: In the present study, the effects of competitive cations NH4⁺, K⁺, Ca²⁺, Na⁺, Mg²⁺ and Li⁺ and co-anions Cl- and Br- on ion exchange of heavy metals Pb2+, Fe3+, Cr3+ and Cu²⁺ on clinoptilolite is examined. The presence of cations and anions in the solutions of heavy metals is reducing the removal of the latter and the order of decreasing negative effect is the following: NH4+ > Mg2+ > Ca²⁺ > Na+ > K+ > Li+ and Br- > Cl- for Pb²⁺ NH4+ > K+ > Ca2+ > Na+, Mg2+ approximate to Li+ and Br- > Cl- for Cr³⁺, NH4⁺ > K+ > Na+ > Ca2+ > Li+ > Mg2+ and Cl- > Br- for Fe3+ and Ca²⁺ > NH4⁺ > Li⁺ > K+ > Na+ > Mg2+ and Cl- > Br- for Cu2+. In all cases, the selectivity of clinoptilolite for heavy metals is the following: Pb2+ > Fe3+ > Cr3+ >= Cu²⁺. (C) 2005 Elsevier B.V. All rights reserved.

Keywords: Clinoptilolite, Heavy Metals, Ion Exchange, Competitive Cations, Anion Complexes, Natural Clinoptilolite, Sieve Properties, Zeolites, Removal, Sedimentary, Mordenite, Sorption, Water

? Atia, A.A., Donia, A.M. and Shahin, A.E. (2005), Studies on the uptake behavior of a magnetic Co₃O₄-containing resin for Ni(II), Cu(II) and Hg(II) from their aqueous solutions. Separation and Purification Technology,