Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China.
Chemosphere. 2013 Feb;90(5):1573-80. doi: 10.1016/j.chemosphere.2012.07.047. Epub 2012 Aug 22.
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°C). The results showed that 2,4,4'-CB was completely decomposed by persulfate at 30°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 (SO(4)(•-)) were predominant under acidic condition and hydroxyl radicals ((•)OH) 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.
过硫酸盐因其高效降解有机污染物而受到越来越多的关注。本文研究了在近环境温度（10-40°C）下，没有活化剂的情况下，过硫酸钠对选定的多氯联苯（PCB）的转化。结果表明，在 30°C 下，2,4,4'-CB 在 8 小时内被过硫酸盐完全分解。通过气相色谱-质谱联用（GC-MS）鉴定了产物，并可以将转化途径分为脱氯和羟基化两个步骤。电子顺磁共振（EPR）技术用于在环境温度下不同 pH 值下识别生成的自由基种类。结果表明，在酸性条件下，硫酸根自由基（SO(4)(•-))占主导地位，而在碱性条件下，羟基自由基（(•)OH）占主导地位。这一行为也通过猝灭研究和动力学模型得到了证实。降低溶液 pH 值会提高 2,4,4'-CB 的降解效率。此外，还研究了过硫酸盐对其他 PCB，如 2-CB、4-CB、2,4-CB、2,4'-CB 和 2,4,6-CB 的降解情况。本研究的结果可以为过硫酸盐修复 PCB 污染土壤和水提供指导。
