자외선 광분해, 염소 처리 및 자외선-염소처리를 통한 조류기인 유기물질 β-cyclocitral과 β-ionone의 분해 기작 규명에 관한 연구

학위논문 (석사)-- 서울대학교 보건대학원 환경보건학과, 2017. 8. 조경덕.Algal taste and odor compound has become one of emerging concerns affecting drinking water quality. Among several algal odorants, β-cyclocitral and β-ionone are the oxidation byproducts of β-carotene existing in algae cells. Several AOPs such as UV-H2O2 and ozonation had adapted for algal odorants. However, degradation kinetic and byproducts of β-cyclocitral and β-ionone under UV-chlorination is not studied much. For these reasons, two odorants were treated by UV photolysis, chlorination and UV-chlorination and the degradation kinetic and byproducts of three treatment were examined. β-ionone showed faster degradation under all reactions compared to β-cyclocitral. The double bond on carbon chain of β-ionone is a reactive site for chlorination, hydroxyl radical attack and UV induced isomerization. Among three reaction, UV-chlorination was the most effective treatment due to generation of hydroxyl radical by reaction between UV and chlorine. Alkaline pH was not favored for UV-chlorination because hypochlorite is dominant form of active chlorine at alkaline pH and it is able to consume hydroxyl radical and it is inefficient for generating hydroxyl radical. During UV-chlorination reaction, only chloroform was generated for byproducts of reaction among regulated VOCs. It is due to methyl ketone functional group of the parent compounds. UV-chlorination had enhanced the formation of chloroform compared to chlorination. However increased amount of chloroform is very little compared to guideline limit. By GC-MS scanning, several intermediates of β-ionone under UV-chlorination were observed including β-cyclocitral. These compounds were formed by UV isomerization, hydroxyl radical attack and bond scission reaction.Abstract i List of Figures ii List of Tables iii 1. Introduction 1 1.1. Background 1 1.2. Objectives 4 2. Material and Methods 4 2.1. Chemicals 4 2.2. Experimental setup 5 2.3. Analysis 6 3. Results 8 3.1. Degradation kinetic of β-cyclocitral and β-ionone under UV photolysis, chlorination and UV-chlorination 8 3.2. pH dependency of degradation kinetic of β-cyclocitral and β-ionone under UV-chlorination 11 3.3. Degradation byproducts of β-cyclocitral and β-ionone under UV photolysis, chlorination and UV-chlorination 12 3.4. Suggested degradation pathway of β-cyclocitral and β-ionone under UV photolysis, chlorination and UV-chlorination 14 4. Conclusions 19 References 21Maste