Chemical Engineering / Kimya Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/14
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Article Citation - WoS: 8Citation - Scopus: 9Indoor Air Quality in Chemical Laboratories(Elsevier Ltd., 2016) Ugranlı, Tuğba; Güngörmüş, Elif; Sofuoğlu, Aysun; Sofuoğlu, Sait CemilChemical laboratories are special microenvironments, in which many pollutants may be found because of the large range and number of chemicals that can be used, while concentrations of some specific ones may relatively be elevated due to high source strengths depending on the type and the number of experiments conducted and the number of people working in the laboratory. Laboratories can be considered as public places for the students whereas they are occupational microenvironments for their staff (technicians, specialists and teaching/research assistants). Hence, laboratory indoor air quality (IAQ) is of importance due to chronic, toxic and carcinogenic health risks for the staff in addition to possible acute effects for both staff and students. This chapter presents background information regarding pertinent indoor air pollutants, factors that determine their concentrations, indoor environmental comfort, a review of the literature on indoor environmental quality in chemical laboratories and measures of IAQ management.Article Citation - WoS: 14Citation - Scopus: 15Chitosan-Immobilized Pumice for the Removal of As(v) From Waters(Springer Verlag, 2014) Turan, Dilek; Kocahakimoğlu, Cemre; Boyacı, Ezel; Sofuoğlu, Sait Cemil; Eroğlu, Ahmet EminA novel sorbent, chitosan-immobilized pumice, has been prepared for the sorption of As(V) from waters prior to its determination by hydride generation atomic absorption spectrometry. The success of the immobilization has been checked with such characterization techniques as scanning electron microscopy, thermal gravimetric analysis, and elemental analysis. Points of zero charge of the sorbents were determined with potentiometric mass titration. Batch-type equilibration studies have shown that the novel sorbent can be employed at a wide pH range resulting in quantitative sorption (>90 %) at pH 3.0-7.0 and greater than 70 % sorption at pH >8.0. These results demonstrate the advantage of immobilizing chitosan onto pumice, because, under the same conditions, pumice displays <20 % sorption toward As(V), whereas chitosan gives approximately 90%sorption only at pH 3.0. The validity of the method was verified through the analysis of ultrapure, bottled drinking, and tap water samples spiked with arsenate; the respective sorption percentages of 93.2 (±0.7), 89.0 (±1.0), and 80.9 (±1.3) were obtained by batch-type equilibration. Arsenic sorption was also examined in the presence of common interfering ions resulting in competing effects of PO3- 4 and NO- 3on As(V) adsorption.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.