Yazar "Pehlivan, E" seçeneğine göre listele
Listeleniyor 1 - 7 / 7
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Adsorption of Cr(III) ions by Turkish brown coals(ELSEVIER SCIENCE BV, 2005) Gode, F; Pehlivan, EThe equilibrium and kinetic properties of Cr(III) ion adsorption by two brown coals from Anatolia, Turkey, have been investigated in batch stirred-tank experiments. The effects of adsorbent dose, initial sorbate concentration and contact time on the adsorption of Cr(III) by Isparta-Yalvac-Yarikkaya (YK) and Kasikara (KK) brown coals were evaluated. The Cr(III) ions are able to form complex compounds with carboxylic and phenolic groups of brown coals and they were also bounded with phenolic groups even at low pH reaction of the solution (< 3). Mechanisms including ion exchange, complexation and adsorption to the surface are possible in the sorption process. Our batch adsorption studies show the equilibrium adsorption data fit the linear Langmuir adsorption isotherm. Adsorption equilibrium was achieved in about 15-20 min for chromium(III). The Langmuir adsorption isotherm was used to describe the observed sorption phenomena. The maximum equilibrium uptake was 0.05 mmol of Cr(III)/g for KK, and 0.26 mmol of Cr(III)/g for YK, respectively, at a pH of 4.5. More than 90% of chromium(III) was removed by KK and YK from an aqueous solution after 60 min. In every experiment, the maximum Cr(III) was sequestered from the solution within 60 min. It is proposed that KK and YK brown coals can be used as potential sorbents for Cr(III) removal from aqueous solutions. (c) 2004 Elsevier B.V. All rights reserved.Öğe Analysis of polychlorinated dibenzofurans (PCDFs) isomers in soil samples(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY, 2001) Pehlivan, M; Pehlivan, EThis study presents an analytical method for the separation of a series of polychlorinated dibenzofurans (PCDFs) emitted to the soil. PCDF contaminants were concentrated from soil samples and isolated from other materials by chromatographic methods and their quantitative determinations were performed by GC/MS (gas chromatography/mass spectroscopy).Öğe Electrochemical investigation of binding of heavy metal ions to Turkish lignites(WILEY-V C H VERLAG GMBH, 2004) Pehlivan, E; Richardson, A; Zuman, PAdsorption and desorption of Cu2+, Ph2+, Cd2+, Ni2+ and Zn2+ ions on samples of lignites (young brown coal) from three areas in the vicinity of Konya (Anatolia, Turkey) were followed using the polarographic method of analysis. This method enables the determination of free metal ions in suspensions containing both small and colloidal particles of lignite. Effects of pH, nature of the metal ion, and origin of the lignite on its adsorption capacity were followed. Binding is only between 5 and 30% reversible, indicating that ion exchange is not the predominant factor. The role of the size and shape of cavities inside pulverized lignite and of the functional groups inside these cavities was considered.Öğe The identification and quantitative analysis of the very toxic 2,3,7,8-tetrachlordibenzo-P-dioxin in the presence of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) contaminated soil samples(MARCEL DEKKER INC, 1999) Pehlivan, M; Pehlivan, E; Ozler, MA; Barlas, HThis research decribes the nature and extent of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) contamination in the soil samples from a waste cable incineration plant. The samples are collected at different places in the nearest and far away points of the soil around the incineration plant. A procedure which is described for the selective separation of 2,3,7,8-TCDD from ail other PCDDs and PCDFs fractionated on Alumina Woelm B Super 1 in such a manner that all PCDDs and PCDFs are eluted prior to 2,3,7,8-TCDD. This procedure allows more sensitive quantitative determination of 2,3,7,8-TCDD in the soil samples.Öğe Ion exchange equilibria of heavy metals in aqueous solution on new chelating resins of sporopollenin (vol 24, pg 195, 1995)(ELSEVIER SCIENCE BV, 1995) Ersoz, M; Pehlivan, E; Duncan, HJ; Yildiz, S; Pehlivan, M[Abstract not Available]Öğe Recent studies on activated carbons and fly ashes from Turkish resources(TAYLOR & FRANCIS INC, 2006) Demirbas, A; Arslan, G; Pehlivan, EThis article deals with adsorptive properties of activated carbons (ACs) and fly ashes from Turkish coal and biomass resources. ACs because of their high surface area, microporous character and the chemical nature of their surface have been considered potential adsorbents for the removal of heavy metals from industrial wastewater. Pyrolysis is an established process method for preparation of activated carbon from biomass. The bio-char is can be used as AC. The adsorption properties of ACs were strictly defined by the physicochemical nature of their surface and their texture, i.e., pore volume, pore size distribution, surface area. It is well known that the pH of the solution-adsorbant mixture is an important variable in the adsorption process. Fly ash has the highest adsorption capacity (198.2 mg/g) for Cd(II). Almond shell AC has the lowest adsorption capacity (2.7 mg/g).Öğe Removal of Cr(VI) from aqueous solution by two Lewatit-anion exchange resins(ELSEVIER SCIENCE BV, 2005) Gode, F; Pehlivan, EThe sorption of hexavalent chromium, Cr(VI), from aqueous solutions on macroporous resins containing tertiary amine groups (Lewatit MP 62 and Lewatit M 610) was studied at varying Cr(VI) concentrations, adsorbent dose, pH, contact time and temperatures. The concentration of chromium in aqueous solution was determined by inductively coupled plasma spectrometry (ICP-AES). Batch shaking sorption experiments were carried out to evaluate the performance of Lewatit MP 62 and Lewatit M 6 10 anion exchange resins in the removal of Cr(VI) from aqueous solutions. The ion-exchange process, which is pH dependent, shows maximum removal of Cr(VI) in the pH range 2-6 for an initial Cr(VI) concentration of 100ppm. The sorption increases with the decrease in pH and slightly decreases with the increase in temperature. Both ion exchangers had high bonding constants with Lewatit M 610 showing stronger binding. It was observed that the maximum adsorption capacity of 0.40 mmol of Cr(VI)/g for Lewatit NIP 62 and 0.41 mmol of Cr(Vl)/g for Lewatit M 610 was achieved at pH of 5.0. The thermodynamic parameters (free energy change, Delta G degrees; enthalpy change, Delta S degrees; and entropy change, Delta H degrees) for the sorption have been evaluated. The rise in temperature caused a slight decrease in the value of the equilibrium constant (K-c) for the sorption of Cr(VI) ion. The sorption of Cr(VI) on the resin was rapid during the first 15 min and equilibrium was found to be attained within 30 min. The sorption of Cr(VI) onto the resins followed reversible first-order rate kinetics. Such ion exchange resins can be used for the efficient removal of chromium from water and wastewater. (c) 2004 Elsevier B.V. All rights reserved.
