119th General Meeting of the KCS

Type Poster Presentation
Area 환경에너지
Room No. 포스터발표장
Time 4월 20일 (목요일) 11:00~12:30
Code ENVR.P-503
Subject Enhanced transformation of atenolol during water treatment with chlorine and UV: roles of N-Cl photolysis
Authors 라지운, 이윤호1,*
GIST 환경공학과, Korea
1GIST 지구환경공학부, Korea
Abstract Atenolol, a b-blocker and trace organic contaminant found in drinking water sources, is poorly eliminated in water chlorination despite of the high reactivity of its secondary amine moiety toward chlorine forming N-Cl atenolol. It has been shown that N-Cl atenolol is readily back-transformed to the parent structure in post de-chlorination step with sulfite. The transformation of atenolol can be significantly enhanced when chlorination is followed by UV (Cl2 + UV) or combined with UV irradiation (UV/Cl2) due to the photolysis of N-Cl atenolol. To better understand the fate of atenolol during water treatment with chlorine and UV, this study investigated the kinetics and products of the UV photolysis of N-Cl atenolol. The fluence-based first-order transformation rate constant of N-Cl atenolol was 2.2´10-3 cm2/mJ (kUV,atenolol= 3´10-5 cm2/mJ), indicating that the N-Cl moiety can be significantly photo-transformed at typical UV doses for UV-based advanced oxidation process (e.g., >100 mJ/cm2). Several transformation products were identified by LC-QTOF-MS analysis from the photolysis of N-Cl atenolol, such as products with m/z of 225, 239 and 265. The formation of these products could be explained by 1) N-Cl photolysis and formation of the N-centered radical, 2) radical shift from the N to the neighboring carbons, 3) peroxyl radical formation via oxygen addition, and 4) imine formation and hydrolysis. Implications of the findings from this study will be discussed with regard to the transformation of amine-containing compounds during water treatment with chlorine and UV.
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