Transformation of polychlorinated biphenyls by persulfate at ambient temperature
Transformation of polychlorinated biphenyls by persulfate at ambient temperature
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DOI：
10.1016/j.chemosphere.2012.07.047
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发表时间：
2013-02-01
期刊：
影响因子：
8.8
通讯作者：
Wang, Yu-Jun
中科院分区：
文献类型：
--
作者：
Fang, Guo-Dong;Dionysiou, Dionysios D.;Wang, Yu-Jun
过硫酸盐因其对有机污染物的高效降解而日益受到人们的关注。本文研究了过硫酸钠在近环境温度（10-40℃）下对一种多氯联苯（PCB）的转化。结果表明，2,4,4′-CB在30℃条件下可在8 h内被过硫酸盐完全分解，产物经气相色谱-质谱联用（GC-MS）鉴定，转化过程可分为脱氯和羟基化两个步骤。采用电子顺磁共振（EPR）技术鉴定了不同pH值下环境温度下生成的自由基种类。结果表明：酸性条件下以硫酸根自由基（SO4中心点-）为主，碱性条件下以羟基自由基（OH - o中心点）为主；淬火研究和动力学模型也证实了这一行为。降低溶液pH可提高2,4,4′-CB的降解效率。此外，还研究了过硫酸盐对其他多氯联苯如2-CB、4-CB、2,4-CB、2,4'-CB和2,4,6-CB的降解情况。本研究结果可为过硫酸盐修复多氯联苯污染的土壤和水体提供指导。(C) 2012 Elsevier Ltd.版权所有：
Increasing attention has been paid to persulfate due to its high efficiency in degrading organic pollutants. This paper investigated the transformation of a selected polychlorinated biphenyl (PCB) by sodium persulfate without activators at near ambient temperature (10-40 degrees C). The results showed that 2,4,4'-CB was completely decomposed by persulfate at 30 degrees C in 8 h. The products were identified by gas chromatography-mass spectrometry (GC-MS), and transformation pathways could be divided into two steps as dechlorination and hydroxylation. Electron paramagnetic resonance (EPR) technique was used to identify the generated radical species at different pH values at ambient temperature. The results showed that sulfate radicals (SO4 center dot-) were predominant under acidic condition and hydroxyl radicals ((OH)-O-center dot) were predominant under basic condition. This behavior was also confirmed by the quenching studies and kinetic model. Decreasing the solution pH resulted in increasing the degradation efficiency of 2,4,4'-CB. Moreover, the degradation of other PCBs such as 2-CB, 4-CB, 2,4-CB, 2,4'-CB, and 2,4,6-CB with persulfate was examined. The findings of this study can provide guidance in the remediation of PCBs contaminated soil and water with persulfate. (C) 2012 Elsevier Ltd. All rights reserved: