Mechanism of metal sulfides accelerating Fe(II)/Fe(III) redox cycling to enhance pollutant degradation by persulfate: Metallic active sites vs. reducing sulfur species
Mechanism of metal sulfides accelerating Fe(II)/Fe(III) redox cycling to enhance pollutant degradation by persulfate: Metallic active sites vs. reducing sulfur species
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金属硫化物加速 Fe(II)/Fe(III) 氧化还原循环以增强过硫酸盐降解污染物的机制：金属活性位点与还原硫物种
DOI：
10.1016/j.jhazmat.2020.124175
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发表时间：
2021-02-15
影响因子：
13.6
通讯作者：
Zhou, Dongmei
中科院分区：
文献类型：
--
作者：
Huang, Min;Wang, Xiaolei;Zhou, Dongmei
金属硫化物（MeSx）可以有效地促进类Fenton反应降解污染物，但其在过硫酸盐（PS）氧化过程中的作用及其机理尚未完全阐明。研究了WS 2、MoS 2、FeS 2和ZnS等不同MeSx对Fe 2 +/PS和Fe 3 +/PS体系降解污染物的影响。结果表明，在Fe 2 +/PS和Fe 3 +/PS体系中，WS 2（0.2g/L）的加入使2，4，4 '-三氯联苯的最大降解率分别提高了5.6倍和16.2倍。MoS 2、FeS 2和ZnS也观察到类似的增强效应，它们可以增强包括磺胺甲恶唑、双酚A和氯苯酚在内的广泛污染物的降解。这些过程的机制进行了进一步的研究，并观察到，Fe（III）/Fe（II）氧化还原循环显着加速MeSx表面，这增加了PS活化产生硫酸根自由基和羟基自由基，证明了表面Fe物种，电子顺磁共振和自由基探测测试的组合分析。表面金属活性中心和还原性硫物种都有助于Fe（II）的再生，但效率随MeSx表面的性质而变化。该研究为改善PS活化的环境修复性能提供了一种新的策略，并全面了解MeSx增强类Fenton反应的机理。
Metal sulfides (MeSx) have been found to be effective in enhancing pollutant degradation by Fenton-like reactions, but their role in persulfate (PS)-based oxidation processes as well as underlying mechanism have not been fully explored. In this study, effects of different MeSx including WS2, MoS2, FeS2 and ZnS on pollutant degradation by Fe2+/PS or Fe3+/PS systems were examined. It was found that the maximum degradation rate of 2,4,4'-trichlorobiphenyl increased by 5.6 and 16.2 times with the addition of WS2 (0.2 g/L) in the Fe2+/PS and Fe3+/PS systems, respectively. Similar enhancement effects were also observed for MoS2, FeS2 and ZnS, which can enhance the degradation of a wide range of pollutants including sulfamethoxazole, bisphenol A and chlorophenol. The mechanism of these processes were further investigated, and it was observed that Fe(III)/Fe(II) redox cycles were dramatically accelerated on MeSx surfaces, which increased PS activation to generate sulfate radicals and hydroxyl radicals, as evidenced by the combined analyses of surface Fe species, electron paramagnetic resonance and radical probing tests. Both surface metallic active sites and reducing sulfur species contributed to Fe(II) regeneration, but the efficiencies varied with the properties of MeSx surface. This study provides a novel strategy for improving the performance of PS activation for environmental remediation and a comprehensive understanding of the mechanism of MeSx enhancing Fenton-like reactions.