Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China.
Environ Sci Technol. 2013 May 7;47(9):4605-11. doi: 10.1021/es400262n. Epub 2013 Apr 26.
There has been considerable interest in the use of persulfate for in situ chemical oxidation of organic contaminants in soils, sediments, and groundwater. Since humic acid (HA) exists ubiquitously in these environmental compartments, its redox active functional moieties, such as quinones, may play an important role in the oxidation processes of persulfate treatments. Understanding the effects of HA, especially the quinone functional groups on the degradation of pollutants by persulfate and the production of sulfate radicals (SO4(•-)) from persulfate, is beneficial for devising effective and economically feasible remediation strategies. In this study, the effects of model quinone compounds and HA on the degradation of 2,4,4'-trichlorobiphenyl (PCB28) by persulfate and the production of SO4(•-) from persulfate were investigated. It was found that quinones and HA can efficiently activate persulfate for the degradation of PCB28. The mechanism of persulfate activation was elucidated by quenching and electron paramagnetic resonance (EPR) studies. The results indicated that production of SO4(•-) from persulfate and quinones was semiquinone radical-dependent. The effects of quinone concentrations were also studied. The findings of this study elucidated a new pathway of persulfate activation, which could degrade environmental contaminants efficiently and provide useful information for the remediation of contaminated soil and water by persulfate.
过硫酸盐在原位化学氧化土壤、沉积物和地下水中的有机污染物方面引起了相当大的关注。由于腐殖酸（HA）普遍存在于这些环境介质中，其氧化还原活性官能团，如醌，可能在过硫酸盐处理的氧化过程中发挥重要作用。了解 HA（尤其是醌官能团）对过硫酸盐降解污染物和过硫酸盐产生硫酸根自由基（SO4(•-)）的影响，有利于设计有效和经济可行的修复策略。在这项研究中，研究了模型醌化合物和 HA 对过硫酸盐降解 2,4,4'-三氯联苯（PCB28）和过硫酸盐产生 SO4(•-)的影响。结果表明，醌和 HA 可以有效地激活过硫酸盐来降解 PCB28。通过猝灭和电子顺磁共振（EPR）研究阐明了过硫酸盐的活化机制。结果表明，过硫酸盐和醌产生 SO4(•-)与半醌自由基有关。还研究了醌浓度的影响。本研究阐明了一种新的过硫酸盐活化途径，可有效降解环境污染物，并为过硫酸盐修复污染土壤和水提供有用信息。
