硫化
零价铁
可渗透反应墙
脱氯作用
化学
三氯乙烯
环境修复
反应速率常数
地下水修复
动力学
受污染的地下水
无机化学
环境化学
硫黄
有机化学
生物降解
污染
吸附
物理
生物
量子力学
生态学
作者
Li Gong,Xiaojiang Qiu,Chen Dong,Yao Hu,Zaizhi Zhang,Qunsen Yuan,Dezhi Yang,Chengshuai Liu,Liyuan Liang,Feng He
标识
DOI:10.1021/acs.est.1c03784
摘要
Sulfidated zero-valent iron (S-ZVI) enhances the degradation of chlorinated hydrocarbon (CHC) in contaminated groundwater. Despite numerous studies of S-ZVI, a versatile strategy to improve its dechlorination kinetics, electron efficiency (εe), and dechlorination capacity is still needed. Here, we used heteroatom incorporation of N(C) and S by ball-milling of microscale ZVI with melamine and sulfur via nitridation and sulfidation to synthesize S-N(C)-mZVIbm particles that contain reactive Fe-NX(C) and FeS species. Sulfidation and nitridation synergistically increased the trichloroethene (TCE) dechlorination rate, with reaction constants kSA of 2.98 × 10-2 L·h-1·m-2 by S-N(C)-mZVIbm, compared to 1.77 × 10-3 and 8.15 × 10-5 L·h-1·m-2 by S-mZVIbm and N(C)-mZVIbm, respectively. Data show that sulfidation suppressed the reductive dissociation of N(C) from S-N(C)-mZVIbm, which stabilized the reactive Fe-NX(C) and reserved electrons for TCE dechlorination. In addition to lowering H2 production, S-N(C)-mZVIbm dechlorinated TCE to less reduced products (e.g., acetylene), contributing to the material's higher εe and dechlorination capacity. This synergistic effect on TCE degradation can be extended to other recalcitrant CHCs (e.g., chloroform) in both deionized and groundwater. This multiheteroatom incorporation approach to optimize ZVI for groundwater remediation provides a basis for further advances in reactive material synthesis.
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