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论文类型：期刊论文

发表时间：2015-12-30

发表刊物：JOURNAL OF HAZARDOUS MATERIALS

收录刊物：SCIE、EI、PubMed、Scopus

卷号：300

页面范围：354-358

ISSN号：0304-3894

关键字：Triclosan; 2 '-HO-BDE-28; Reactive oxygen species; Excited singlet states; Excited triplet states

摘要：Hydroxylated polyhalogenated diphenyl ethers (HO-PXDEs) have been recognized as a group of widely detected emerging contaminants in natural waters. Photolysis was proved to be an important transformation pathway for these compounds and their direct phototransformation results in highly toxic dioxins. However, the roles of excited states and reactive oxygen species in the photochemical transformation of these compounds are still unclear. In this study, 2'-HO-2,4,4'-trichlorodiphenyl ether (triclosan) and 2'-HO-2,4,4'-tribromodiphenyl ether (2'-HO-BDE-28) were selected as model compounds to investigate their phototransformation processes. Results showed that the direct photolysis reactions of both triclosan and 2'-HO-BDE-28 occurred via their respective excited singlet states, leading to the generation of dioxins. In addition, the energy and electron transfer reactions between excited states of model compounds and molecular O-2 can lead to the generation of O-1(2) and (OH)-O-center dot, which results in self-sensitized photolysis. We also found that both the k, Phi dioxin yield for anionic triclosan were higher than those of anionic 2'-HO-BDE-28. This study revealed the roles of the excited states in direct photolysis and the generation pathway of reactive oxygen species in self-sensitized photolysis of HO-PXDEs, which is important for understanding the phototransformation mechanisms of HO-PXDEs. (C) 2015 Elsevier B.V. All rights reserved.