Browsing by Author "Ziylan, Asu."

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    Destruction of analgesic and anti-inflammatory pharmaceuticals in water by catalytic and advanced oxidation processes
    (Thesis (Ph.D.) - Bogazici University. Institute of Environmental Sciences, 2017., 2017.) Ziylan, Asu.; İnce, Nilsun H.
    The present study aims to emphasize the occurrence of pharmaceutical residues in water and their treatability in homogeneous and heterogeneous solutions by advanced oxidation processes utilizing ultrasound and a variety of solid catalysts. Hence, an important part of the study is the synthesis of metallic nanoparticles/nanocomposites and the assessment of their catalytic activity in the destruction of pharmaceuticals in water. One of the main highlights of the study is the higher efficiency of heterogeneous processes that were assisted by ultrasound than homogeneous systems due to the properties of ultrasound accelerating the transfer of organic solutes to the solid surfaces, where they adsorbed and reacted with many different reactive species. A second highlight of the research is the utility of ultrasound in modification of conventional catalysts such as titanium dioxide and alumina to enable the synthesis of platinum, gold and palladium-supported nanocomposites. The method was demonstrated to enhance the catalytic activity of the catalysts via the electron-trapping ability of the co-catalyst, the massive surface area, increased number of adsorption sites and e- transfer from co-catalyst for enhanced rate of OH production. Finally, hybrid processes (e.g. sono-ozonation, sono-photolysis, sono-photo-ozonation) was more efficient than singles leading to the generation of excess radical species.
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    Pretreatment of biocide containing wastewaters by advanced oxidation processes
    (Thesis (M.S.)-Bogazici University. Institute of Environmental Sciences, 2009., 2009.) Ziylan, Asu.; İnce, Nilsun.; Üstün, Beyza.
    Biocide is an antimicrobial agent used in various industrial applications to control the bacterial growth that leads to environmental, ecological and toxicological problems in water. The discharge effluents from manufacturing, production and industrial applications contain complex and diverse groups of chemicals. These effluents are hard to treat by conventional treatment methods because of the inhibitive effect of biocides on bacterial growth in biological treatment process. Advanced Oxidation Processes (AOPs) have the ability to generate short-lived, powerful hydroxyl radicals (•OH) that readily attack and destroy contaminants in wastewaters. The purpose of the study was to investigate the most suitable process (or processes) and its optimal operating conditions for the pre- or post-treatment of hexahydrotriazine (HHT) containing wastewaters (in an ultrasonic bath operated individually, sequentially (before an ultrasonic probe) or simultaneously with an advanced oxidation process (AOP)). It was found that a low power ultrasonic bath alone was an ineffective method for sufficient degradation of HHT to render biodegradability or organic matter destruction, but its sequential operation with an ultrasonic probe, or simultaneous operation with photo-Fenton process were very effective, particularly for enhancing the biodegradability of the solution. The synergy was the result of increased mass transfer rates and OH radical formation under ultrasonic irradiation.|Keywords: biocide, hexahydrotriazine, advanced oxidation, ultrasound