水相中Cl-、Fe(III)对多溴联苯醚光化学转化过程中活性物种形成的影响机制研究

Polybrominated diphenyl ethers (PBDEs) and its derivatives have higher ecological risks. Human production and living activities are the major sources of these organic pollutants. The previous research of the applicant found that OH-PBDEs were generated from PBDEs in aqueous Fe(III) and/or fulvic acid solutions and in surface water under simulated solar light irradiation. The liquid chromatography-triple quadrupole mass spectrometer (LC-MS/MS) and electron spin resonance (ESR) results indicated that the formation of OH-PBDEs likely resulted from the additive reaction of aryl radical and •OH. This study suggested a possible abiotic origin of OH-PBDEs formation in the aquatic environment. Therefore, based on the results of the previous research, several PBDEs are selected as the model compounds, and their phototransformation mechanisms, the identification and function of the active species in water, and the effect of chloride and ferric ion are fully investigated. This research will be helpful for gaining a better understanding of the likely fate and ecological risk of PBDEs in the aquatic environment.

多溴联苯醚(PBDEs)及其衍生物普遍具有较高的生态风险。申请人前期研究中发现：氙灯照射下，在含三价铁离子(Fe(III))和/或富里酸的溶液、实际地表水中， BDE-47均可通过光致羟基化反应产生羟基多溴联苯醚(OH-PBDEs)。该研究的LC-MS/MS和ESR检测结果显示，BDE-47产生的芳基自由基和由Fe(III)等水环境因子产生的羟基自由基为主要活性物种，从而证明了地表水中PBDEs光致羟基化可能是OH-PBDEs的一个天然形成途径。基于前期研究，进一步开展含氯离子(Cl-)、Fe(III)的水相中PBDEs光化学转化机理和光转化过程中活性物种识别的研究、探讨Cl-和Fe(III)对活性物种产生和PBDEs光化学转化的影响机制，对全面了解水中PBDEs光化学转化过程，评价其水生生态风险具有重要的环境意义。

氯离子与三价铁离子广泛存在与水环境中，在不同的光化学反应体系中可以通过多种形式影响有机污染物的化学转化。本项目以多溴联苯醚BDE-47为模型化合物，研究了Cl-和Fe(III)等环境因子对于BDE-47光化学转化的影响机理和规律，对光转化过程中活性物种进行了识别。结果显示：在含Cl-、Fe(III)等的影响下，BDE-47的转化速率明显提高，能够发生包括脱溴、氯代和羟基化等在内的光化学转化过程；水相中 Cl-、Fe(III)，以及富里酸、pH值、光强等因子均对上述转化过程中的羟基自由基、氯自由基、以脱溴和/或氢产生的芳环自由基等活性物种有重要的影响。该项目有助于全面了解重要水环境因子对多溴联苯醚光化学转化过程的作用机制，对评价其水生生态风险具有重要的环境意义和学术价值。