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Title: | 環境水體苯並三唑類藥物之流佈與光降解機制 The Occurrence and Photolysis of Benzotriazole and 5-Methyl-1H-Benzotriazole in the Aquatic Environment |
Authors: | Kenneth Hsien-Yung Chung 鍾先洋 |
Advisor: | 林郁真(Angela Yu-Chen Lin) |
Keyword: | 苯並三唑,5-甲基-1H-苯並三唑,光降解,紫外光吸收劑,宿命, photodegradation,ultraviolet absorbers,benzotriazole,5-methyl-1H-benzotriazole,fate, |
Publication Year : | 2017 |
Degree: | 碩士 |
Abstract: | Benzotriazole and 5-methyl-1H-benzotriazole have been broadly used in industrial applications such as corrosion inhibitors, anti-icing fluids, and ultraviolet absorbers or photostabilizers. Due to their limited biodegradation and sorption tendencies, benzotriazole and 5-methyl-1H-benzotriazole have been widely detected in surfaces waters. Concentration of benzotriazole and 5-methyl-1H-benzotriazole were determined in two rivers and a wastewater treatment plant (WWTP) in northern Taiwan. Concentrations remained steady in Keelung River ranging from 179 ng/L to 251 ng/L for benzotriazole and 25 ng/L to 139 ng/L for 5-methyl-1H-benzotriazole. In Dahan River, higher concentrations of benzotriazole and 5-methyl-1H-benzotriazole were detected at 1565 ng/L and 226 ng/L, respectively. Removal of benzotriazole and 5-methyl-1H-benzotriazole was negligible in the WWTP.
Benzotriazole showed the ability to act as an ultraviolet absorber and/or photostabilizer in surface waters by reducing the quantum yield of ·OH in nitrate photolysis, hindering dissolved organic matter deterioration under simulated sunlight, and altering the fate of pharmaceutical residues in surface waters, such as that of methotrexate. The photochemical fate of benzotriazole and 5-methyl-1H-benzotriazole themselves was studied. Direct photolysis half-lives were 56.9 and 14.0 hours for benzotriazole and 5-methyl-1H-benzotriazole, respectively. The presence of nitrate and DOM increased the photolysis rate of both target compounds, but were not the determining factors of the target compounds’ fate. Neither benzotriazole nor 5-methyl-1H-benzotriazole have the specific structural moieties in which bicarbonate radicals show affinity towards. Also, ·OH produced from nitrate photolysis is more likely to react with bicarbonate by a near-factor of 10 rather than the target compounds. Negligible enhancement for benzotriazole and significantly slowed photolysis rate for 5-methyl-1H-benzotriazole were observed in the nitrate-bicarbonate system. Photolysis of benzotriazole and 5-methyl-1H-benzotriazole in actual river water closely resembled the photolysis in the nitrate-bicarbonate system. These results suggest that the nitrate-bicarbonate system dictates the fate of benzotriazole and 5-methyl-1H-benzotriazole in surface waters. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/59789 |
DOI: | 10.6342/NTU201700420 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 環境工程學研究所 |
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