Boğaziçi Üniversitesi Tezleri
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Browsing Boğaziçi Üniversitesi Tezleri by Subject "Absorption."
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Item Assessment of molecular size distribution effects on the nonselective oxidation of trace metal humic acid binary system(Thesis (M.S.)-Bogazici University. Institute of Environmental Sciences, 2010., 2010.) İlhan, Esra Değirmenci.; Bekbölet, Miray.The objective of this research to investigate the effects of zinc ions on the nonselective photocatalytic degradation of humic acid in aqueous medium. The photocatalytic oxidation of humic was carried out using TiO2 Degussa P-25 as the photocatalyst. The degradation kinetics was assessed based on pseudo first order. The complex interactions between the surface properties of titanium dioxide and the molecular size dependent fractions of the humic acid were studied. The role of the metal ion complexation as expressed by the “binary system effect” on the photocatalytic degradation efficiency of humic acids with respect to molecular size fractions was deduced. The experiments were conducted with different molecular size fractions such as raw, 0.45 μm filtered fraction, 100 kDa fraction and 30 kDa fraction of Aldrich humic acid solution in the presence and the absence of zinc ion The molecular and structural characteristics of the humic acid molecule relative to changes during photocatalytic oxidation were evaluated on a comparative basis by UV-vis and fluorescence spectroscopy. The declining trend of the specified UV-vis parameters, the related changes in the fluorescence spectra indicated the oxidative degradation of humic acid. As confirmed by the spectroscopic evaluation of the molecular size distribution, photocatalytic degradation of humic acid led to the formation of lower molecular size and higher UV-absorbing compounds.|Keywords: Humic Acid, Photocatalytic degradation, Adsorption, Molecular Size Fraction, Zinc.Item Modification and expansion of a computer aided design package for process flowsheet development(Thesis (M.S.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 1986., 1986.) Dizdaroğlu, Gülseda.; Hortaçsu, Öner.; Kuru, Selahattin,An interactive design calculation package (DESPAC), prepared under the direction of Prof. A. Westerberg at Carnegie-Mellon University, contains flash, disti'llation and absorption routines. In this study DESPAC was firstly modified from the DEC-20 computer system to the CDC Cyber 170/815 computer system and then expanded by adding the multicomponent liquid-liquid extraction and the shell-and-tube heat exchanger computation modules. The new package (DESPAC2) is capable of solving steady-state problems for various process flowsheets on a unit by unit basis. DESPAC2 has a library file which comprises some thermophysical properties for ninety-one chemical species. This file can be extended defining new properties and components. In addition to this, it is possible to introduce new unit computations into DESPAC2. The methodology required for this purpose, is explained in detail. In order to present the flexibility of DESPAC2, various examples are solved. Firstly six problems involving single operation units are studied. Secondly various flowsheets are proposed and tested for a separation problem as an example of flowsheet development using DESPAC2. This package is simple to use and can be employed for wide range of applications including flowsheet development, process design, in research and education.