Qu Ruijuan, Feng Mingbao, Wang Xinghao, Huang Qingguo, Lu Junhe, Wang Liansheng, Wang Zunyao
State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Jiangsu Nanjing, P. R. China.
College of Agricultural and Environmental Sciences, Department of Crop and Soil Sciences, University of Georgia, Griffin, Georgia, United States of America.
PLoS One. 2015 Oct 2;10(10):e0139580. doi: 10.1371/journal.pone.0139580. eCollection 2015.
Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants and has attracted more and more attention. In this work, the parent TBBPA with an initial concentration of 100 mg/L was completely removed after 6 min of ozonation at pH 8.0, and alkaline conditions favored a more rapid removal than acidic and neutral conditions. The presence of typical anions and humic acid did not significantly affect the degradation of TBBPA. The quenching test using isopropanol indicated that direct ozone oxidation played a dominant role during this process. Seventeen reaction intermediates and products were identified using an electrospray time-of-flight mass spectrometer. Notably, the generation of 2,4,6-tribromophenol was first observed in the degradation process of TBBPA. The evolution of reaction products showed that ozonation is an efficient treatment for removal of both TBBPA and intermediates. Sequential transformation of organic bromine to bromide and bromate was confirmed by ion chromatography analysis. Two primary reaction pathways that involve cleavage of central carbon atom and benzene ring cleavage concomitant with debromination were thus proposed and further justified by calculations of frontier electron densities. Furthermore, the total organic carbon data suggested a low mineralization rate, even after the complete removal of TBBPA. Meanwhile, the acute aqueous toxicity of reaction solutions to Photobacterium Phosphoreum and Daphnia magna was rapidly decreased during ozonation. In addition, no obvious difference in the attenuation of TBBPA was found by ozone oxidation using different water matrices, and the effectiveness in natural waters further demonstrates that ozonation can be adopted as a promising technique to treat TBBPA-contaminated waters.
四溴双酚A（TBBPA）是使用最广泛的溴化阻燃剂之一，已引起越来越多的关注。在本研究中，初始浓度为100mg/L的母体TBBPA在pH 8.0条件下经6分钟臭氧化后被完全去除，碱性条件比酸性和中性条件更有利于快速去除。典型阴离子和腐殖酸的存在对TBBPA的降解没有显著影响。使用异丙醇的猝灭试验表明，在此过程中直接臭氧氧化起主导作用。用电喷雾飞行时间质谱仪鉴定出17种反应中间体和产物。值得注意的是，在TBBPA降解过程中首次观察到2,4,6-三溴苯酚的生成。反应产物的演变表明，臭氧化是去除TBBPA及其中间体的有效处理方法。离子色谱分析证实了有机溴依次转化为溴化物和溴酸盐。由此提出了两条主要反应途径，即涉及中心碳原子裂解和苯环裂解并伴随脱溴反应，并通过前沿电子密度计算进一步证实。此外，总有机碳数据表明，即使TBBPA被完全去除，矿化率也很低。同时，在臭氧化过程中，反应溶液对发光菌和大型溞的急性水毒性迅速降低。此外，使用不同水基质进行臭氧氧化时，TBBPA的衰减没有明显差异，在天然水中的有效性进一步证明臭氧化可作为一种有前景的技术用于处理受TBBPA污染的水体。
