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研究报告

Photochemical reaction of 2,4,6-tribromophenol in natural/artificial seawater

摘要：有机溴代苯酚类污染物在水体中普遍存在，尤其在海洋环境中，除人为污染源外，它还存在广泛的天然来源.以2，4，6-三溴苯酚为模型化合物，以氙灯（λ> 290 nm）作为模拟太阳光源，研究了海水中溴代苯酚的光化学过程，并系统考察了溴代苯酚初始浓度、Cl^-、Fe（Ⅲ）和pH值等环境因素的影响.实验结果表明，在海水中，2，4，6-三溴苯酚能够快速发生光化学反应，通过产物分析发现其主要产物为通过光致脱溴氯代过程产生的2，4-二溴-6-氯苯酚，并且该产物随2，4，6-三溴苯酚初始浓度、Cl^-浓度、Fe（Ⅲ）浓度的增大及溶液pH值的降低而增加.以明亮发光杆菌为受试生物的毒理学实验表明，2，4，6-三溴苯酚在海水中光化学的前期，系统的毒性效应增强，而毒性的增加可能主要由光致氯代过程导致.

Abstract：Organic bromophenol pollutants (BPs) are widely present in aquatic environment, especially in marine environment. They can be formed through a variety of natural processes in addition to anthropogenic pollution. In this study, 2,4,6-tribromophenol (2,4,6-TBP) was chosen to investigate the photochemical transformation of BPs in natural/artificial seawater under simulated sunlight (Xe lamp, λ> 290 nm). The effects of initial concentration of 2,4,6-TBP, Cl^-, Fe(Ⅲ) and pH on the photochemical process of 2,4,6-TBP were also studied. The results showed that photochlorination was the main photochemical transformation process of 2,4,6-TBP in seawater under simulated sunlight. Meanwhile, the photo-formation of the main product 2,4-dibromo-6-chlorophenol was enhanced by increasing initial concentrations of 2,4,6-TBP, Cl^- and Fe(Ⅲ), as well as under lower pH. Besides, results of toxicity evaluation performed with photobacterium phosphoreum indicated that the toxicity of seawater spiked with 2,4,6-TBP significantly increased in early irradiation period, which might be ascribed to the chlorination of 2,4,6-TBP.