Photochemical reactions between bromophenols and hydroxyl radical generated in aqueous solution: A laser flash photolysis study
Photochemical reactions between bromophenols and hydroxyl radical generated in aqueous solution: A laser flash photolysis study
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溴酚与水溶液中产生的羟基自由基之间的光化学反应：激光闪光光解研究
DOI：
10.1016/j.jphotochem.2016.12.012
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发表时间：
2017-03-01
影响因子：
4.3
通讯作者：
Quan, Xie
中科院分区：
文献类型：
--
作者：
Jiang, Jingqiu;Zhao, Hongxia;Quan, Xie
溴代酚（BPs）是一些毒性较大的污染物的前体化合物，如羟基化多溴联苯醚（OH-PBDEs）、多溴二苯并二恶英/二苯并呋喃（PBDD/Fs）等，但其环境归趋的相关数据有限，难以对其生态风险进行评估。利用激光闪光光解（LFP）技术研究了8种BPs与NaNO 2产生的羟基自由基（（OH）-O-中心点）的光化学反应。发现了两种瞬态中间产物：OH加合物和溴苯氧基自由基，并提出了可能的反应途径。溴原子的数量和位置通过不同的机制显著影响它们的形成。所有8个溴苯氧基自由基的寿命也被确定为长于100 μ s。在较低的pH值和较高的Fe（III）浓度下，生成更多的OH加合物，而在较高的pH值和Fe（III）浓度下，溴代苯氧基自由基的相对量较大。富里酸（FA）在低浓度时对两种过渡物种的形成有促进作用，而在高浓度时则有抑制作用。这些结果将提供重要的见解，在自然水环境中的BPs的光化学过程。(C)© 2016 Elsevier B. V.版权所有。
Bromophenols (BPs) have been reported as precursor compounds to form some more toxic pollutants such as hydroxylated polybrominated diphenyl ethers (OH-PBDEs), polybrominated dibenzo-p-dioxin/ dibenzofurans (PBDD/Fs), but only limited data about environmental fate of BPs is available to assess their ecological risks. In this study, the photochemical reactions of eight BPs and hydroxyl radical ((OH)-O-center dot) generated from NaNO2 were investigated using laser flash photolysis (LFP) in aqueous solution. Two transient intermediates, OH adducts and bromophenoxyl radicals, were identified after irradiation, and the possible reaction pathways were proposed. Both numbers and positions of bromine atoms significantly affected their formation by different mechanisms. Lifetimes of all eight bromophenoxyl radicals were also determined to be longer than 100 mu s. More OH adducts were generated at lower pH values and higher Fe (III) concentrations, while the relative amounts of bromophenoxyl radicals were bigger at higher pH values and Fe (III) concentrations. In addition, fulvic acid (FA) showed promoting effects for the formation of the two transient species in low concentration, while inhibitive effects in high concentration. These results will provide vital insights into the photochemical process of BPs in natural water environments. (C) 2016 Elsevier B.V. All rights reserved.