Date of Award

11-2017

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Syed Salman Ashraf

Second Advisor

Soleiman Hisaindee

Third Advisor

Mohamed Abdul Rauf

Abstract

Organic pollutants, especially those found in water bodies; pose a direct threat to various aquatic organisms as well as humans. A variety of different remediation approaches, including chemical and biological methods have been developed for the degradation of these organic pollutants. However, comparative mechanistic studies of pollutant degradation by these different systems are almost non-existent. In this study, the degradation of two emerging pollutants an antibiotic pollutant, Sulfamethoxazole (SMX) and a model thiazole pollutant, Thioflavin T (ThT), was carried out using advanced oxidation process (AOP), using UV+H2O2 or a peroxidase enzyme system. Optimization conditions for Sulfamethoxazole degradation by peroxidase enzyme showed an absolute requirement for a redox mediator (Hydroxybenzotriazole) as well as low pH for pollutant degradation. The other conditions for the efficient degradation were as follows: the concentration of hydrogen peroxide, peroxidase enzyme and SMX needed were 56 μM, 78 nM and 5 ppm respectively. The degradation of both pollutants was followed using UV-Vis spectrophotometry and liquid chromatography-mass spectroscopy (LC-MS), and the products formed were identified using tandem liquid chromatography-mass spectrometry-mass spectrometry (LC-MS-MS). The results showed that the two remediation approaches UV+H2O2 and peroxidases produced different sets of intermediates suggesting that different degradation schemes were operating in the two systems (AOP vs. Peroxidase enzyme system). Phytotoxicity studies carried out using Lactuca sativa (lettuce) showed different levels of detoxification of the pollutants by the two different remediation approaches. This is the first time that a detailed comparative study showing in detail the intermediates generated in chemical and biological remediation methods has been presented. Furthermore, the results show that different remediation systems have very different degradation schemes and result in products having different toxicities.

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