School of Environmental Studies & State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China.
Geological Survey Institute, China University of Geosciences, Wuhan 430074, China.
Sci Total Environ. 2019 Nov 25;693:133635. doi: 10.1016/j.scitotenv.2019.133635. Epub 2019 Jul 27.
Although persulfate (PS) activation has been commonly applied to remove organic contaminants on the subsurface, it is valuable to further explore PS activation methods. In this study, a novel combined process based on PS coupled with dithionite was investigated using trichloroethene (TCE) as a typical organic contaminant. PS/dithionite was demonstrated to be an effective system for TCE degradation depending on the operating parameters such as the initial PS and dithionite dosages. The optimal molar ratio of PS/dithionite/TCE was 5/5/1. Sulfate radicals (SO•) were the dominant reactive species responsible for TCE degradation in the PS/dithionite system. Two pathways for SO• generation were proposed in the PS/dithionite system. The generation of SO• increased in the presence of oxygen but was still effective in an anaerobic environment. This study is the first to report a novel combined process based on PS coupled with dithionite, which is expected to be an efficient and environmentally friendly approach for in situ chemical oxidation (ISCO) remediation of contaminated soil and groundwater, whether in aerobic or anaerobic environments.
尽管过硫酸盐（PS）活化已广泛应用于去除地下水中的有机污染物，但进一步探索 PS 活化方法仍然具有重要意义。本研究采用三氯乙烯（TCE）作为典型有机污染物，考察了一种新型的基于 PS 与连二亚硫酸盐结合的联合工艺。结果表明，PS/连二亚硫酸盐是一种有效的 TCE 降解体系，这取决于操作参数，如初始 PS 和连二亚硫酸盐的剂量。PS/连二亚硫酸盐/TCE 的最佳摩尔比为 5/5/1。在 PS/连二亚硫酸盐体系中，硫酸根自由基（SO•）是 TCE 降解的主要反应性物质。在 PS/连二亚硫酸盐体系中提出了两种 SO•生成途径。在有氧存在的情况下，SO•的生成增加，但在厌氧环境中仍然有效。本研究首次报道了一种新型的基于 PS 与连二亚硫酸盐结合的联合工艺，该工艺有望成为一种高效、环保的原位化学氧化（ISCO）修复污染土壤和地下水的方法，无论是在有氧还是厌氧环境中。
