Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection
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Article Citation - WoS: 21Citation - Scopus: 23Activated Carbon Adsorption of Fuel Oxygenates Mtbe and Etbe From Water(Springer Verlag, 2009) İnal, Fikret; Yetgin, Senem; Aksu, Gülsüm T.; Şimşek, Selvi; Sofuoğlu, Aysun; Sofuoğlu, Sait CemilThe aqueous phase adsorption of fuel oxygenates methyl tertiary butyl ether (MTBE) and ethyl tertiary butyl ether (ETBE) onto commercially available granular activated carbon (GAC; Norit GAC 1240) was investigated in a batch system at 27°C. The oxygenate concentrations were determined by headspace gas chromatography/mass spectrometry analyses. The experimental data were used with four two-parameter isotherm models (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich) and two kinetic models (pseudo first-order and pseudo second-order) to determine equilibrium and kinetic parameters. Considering the correlation coefficient and root mean square error, Dubinin-Radushkevich isotherm showed better fit with the equilibrium data for MTBE. However, the performances of Langmuir and Dubinin-Radushkevich models were comparable for ETBE. The adsorption capacities were calculated as 5.50 and 6.92 mg/g for MTBE and ETBE, respectively, at an equilibrium solution concentration of 1 mg/L using Dubinin-Radushkevich isotherm. The differences between the model predictions and experimental data were similar for the pseudo first-order and pseudo second-order kinetic models. Gibbs free-energy changes of adsorption were found to be -22.59 and -28.55 kJ/mol for MTBE-GAC and ETBE-GAC systems, respectively, under the experimental conditions studied.Master Thesis Investigation of Fuel Oxygenate Adsorption on Clinoptilolite Rich Natural Zeolite(Izmir Institute of Technology, 2006) Yetgin, Senem; İnal, FikretThe wide use of fuel oxygenates in gasoline as anti-knocking and emission reduction agent have recently led to serious environmental concerns due to their detection in groundwater and surface water. Among the various gasoline additives, methyl tertiary butyl ether (MTBE) and ethyl tertiary butyl ether (ETBE) are the most frequently used fuel oxygenates worldwide. Due to the physical and chemical properties of fuel oxygenates, the conventional treatment technologies are generally ineffective for their removal from contaminated water. Adsorption is a common process frequently used to remove fuel oxygenates from water. The use of natural zeolites as adsorbent have increased significantly because of their availability and low cost. Clinoptilolite is one of the most abundant zeolites in nature, and Turkey has very large clinoptilolite reserves. In this project the adsorption properties of clinoptilolite rich natural zeolites for use in the removal of MTBE and ETBE from water have been investigated using batch equilibrium and fixed-bed column experiments. The adsorption properties have been compared with those of two activated carbons (i.e., Powdered Activated Carbon (PAC) and Granulated Activated Carbon (GAC)). In addition, bisolute (i.e., benzene and oxygenate) adsorption experiments were also carried out to determine the effectiveness of these adsorbents in the presence of other gasoline hydrocarbons. All the experiments were performed at 25 °C with initial oxygenate and benzene concentrations of 2000 ppb and 400 ppb, respectively. In batch equilibrium experiments, it has been found that the powdered and granulated activated carbons had higher adsorption capacities for MTBE and ETBE than clinoptilolite. The highest capacity for the amount of MTBE adsorbed per unit mass of adsorbent was achieved using GAC while that of ETBE was obtained using PAC. The presence of benzene decreased the adsorption capacities of GAC and PAC. However, the effect of benzene was not clear and was dependent on the adsorbent loading for clinoptilolite. In fixed-bed column experiments, GAC and clinoptilolite were tested as adsorbents. The column breakthrough curves for clinoptilolite were steep indicating fast adsorption and narrow mass transfer region. For GAC, mass transfer regions were wider due to the relatively flat breakthrough curves. There was no significant effect of benzene on the breakthrough curves for GAC and clinoptilolite.