Chemical Engineering / Kimya Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/14
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Article Citation - WoS: 27Citation - Scopus: 31Fluoroacrylate-Aromatic Acrylate Copolymers for Viscosity Enhancement of Carbon Dioxide(Elsevier Ltd., 2019) Kılıç, Sevgi; Enick, Robert M.; Beckman, Eric J.The effect of the structure of aromatic acrylate-fluoroacrylate copolymers on CO2 viscosity at elevated pressures was investigated. These copolymers were all found to be miscible with CO2 at pressures between 10-15 MPa (295 K) and induce an increase in the viscosity to some degree. It appears that stacking of aromatic rings is the key factor in viscosity enhancement. The results showed that viscosity of the solution increases with the increasing content of the aromatic acrylate unit in the copolymer, but a point is reached beyond which additional comonomer causes the relative viscosity to drop, suggesting that the aromatic rings associate through intramolecular rather than intermolecular interactions beyond the optimum value. The most effective CO2 thickener identified in this study was the 29% phenyl acrylate-71% fluoroacrylate copolymer. However, the presence of a spacer (methyl or ethyl) between the backbone and the aromatic group substantially diminished the viscosity enhancement.Article Citation - WoS: 3Citation - Scopus: 5Adsorption Characteristics of Lead-, Barium- and Hydrogen-Rich Clinoptilolite Mineral(SAGE Publications Inc., 2003) Çakıcıoğlu Özkan, Seher Fehime; Ülkü, SemraThe carbon dioxide and water vapour adsorption properties of local clinoptilolite-rich material, both as the original and as lead-, barium- and hydrogen-rich forms, were examined. The lead- and barium-rich forms were prepared by treatment of the original clinoptilolite with Pb(NO3)2 and BaCl2 respectively, while the hydrogen-rich form was prepared by NH4Cl and heat treatment. Water and CO2 adsorption experiments were conducted in a volumetric system under static conditions, with low-pressure adsorption data being used for the characterization of the natural, Pb-rich, Ba-rich and H-rich clinoptilolite samples. Although the existence of barium-exchange was not noted, an appreciable decrease in CO2 adsorption was observed with the Pb-rich and H-rich forms due to a decrease in the electrostatic interaction between the surface and the adsorbate. Application of the Dubinin-Astakhov equation to the water adsorption data established the existence of micropores of different sizes that exhibited different adsorption mechanisms.Article Citation - WoS: 21Citation - Scopus: 22Role of Ph on Co2 Sequestration in Coal Seams(Elsevier Ltd., 2016) Özdemir, EkremThe effect of acidic or basic pre-treatment on the adsorption capacity of CO2 on coals was investigated. Argonne Premium Pocahontas No. 3, Upper Freeport, Pittsburgh No. 8, Lewiston-Stockton, Blind Canyon, Illinois No. 6, Wyodak, and Beulah-Zap coals were washed in weak solutions of H2SO4 and NaOH to the pH values of 10, 7, and 2, after an initial washing in acidic water. Attempts to treat the Wyodak and Beulah-Zap coals were unsuccessful because the base treatment after the initial acid treatment resulted in a suspension which could be separated neither via filtration through a 45 μm filter nor centrifugation. Equilibration took several days in some cases, although the as-received coal had been ground to 150 μm. Acid washing preferentially removed Ca (calcite) and Mg. Aluminosilicate clays were not notably removed. Iron was removed in significant amounts only after base treatment, possibly after it was converted to hematite. The adsorption capacity of CO2 on the acid treated coals was higher than both the base treated and untreated coals. The difference in adsorption capacities for acid and base treated coals was related to the pore sizes and mineral matter removal from the coals, where the calculated average pore size was higher for acid treated coals than for the base treated coals. It is concluded that the pH decrease due to CO2 dissolution in cleat water is favored in coal seam sequestration, which resulted in an increase in storage capacity of coals.Article Citation - WoS: 23Citation - Scopus: 22Exposure To Particulate Matter in a Mosque(Elsevier Ltd., 2012) Ocak, Yılmaz; Kılıçvuran, Akın; Eren, Aykut Balkan; Sofuoğlu, Aysun; Sofuoğlu, Sait CemilIndoor air quality in mosques during prayers may be of concern for sensitive/susceptible sub-groups of the population. However, no indoor air pollutant levels of potentially toxic agents in mosques have been reported in the literature. This study measured PM concentrations in a mosque on Friday when the mid-day prayer always receives high attendance. Particle number and CO 2 concentrations were measured on nine sampling days in three different campaigns before, during, and after prayer under three different cleaning schedules: vacuuming a week before, a day before, and on the morning of the prayer. In addition, daily PM 2.5 concentrations were measured. Number concentrations in 0.5-1.0, 1.0-5.0, and>5.0μm diameter size ranges were monitored. In all campaigns the maximum number concentrations were observed on the most crowded days. The lowest number concentrations occurred when vacuuming was performed a day before the prayer day in two of the three size ranges considered. PM 2.5 concentrations (four-hour samples that integrated before, during, and after the prayer) were comparable to the other indoor environments reported in the literature. CO 2 concentrations suggested that ventilation was not sufficient in the mosque during the prayers. The results showed that better ventilation, a preventive cleaning strategy, and a more detailed study are needed.