Coincorporation of N and S into Zero-Valent Iron to Enhance TCE Dechlorination: Kinetics, Electron Efficiency, and Dechlorination Capacity
Coincorporation of N and S into Zero-Valent Iron to Enhance TCE Dechlorination: Kinetics, Electron Efficiency, and Dechlorination Capacity
复制标题
N和S共掺入零价铁以增强TCE脱氯：动力学、电子效率和脱氯能力
DOI：
10.1021/acs.est.1c03784
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发表时间：
2021-12-07
影响因子：
11.4
通讯作者：
He, Feng
中科院分区：
文献类型：
--
作者：
Gong, Li;Qiu, Xiaojiang;He, Feng
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 (epsilon(e)), 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)-mZVI(bm) particles that contain reactive Fe-N-X(C) and FeS species. Sulfidation and nitridation synergistically increased the trichloroethene (TCE) dechlorination rate, with reaction constants k(SA) of 2.98 x 10(-2) L.h(-1).m(-2) by S-N(C)-mZVI(bm), compared to 1.77 x 10(-3) and 8.15 x 10(-5) L.h(-1).m(-2) by S-mZVI(bm) and N(C)-mZVI(bm), respectively. Data show that sulfidation suppressed the reductive dissociation of N(C) from S-N(C)-mZVIbm, which stabilized the reactive Fe-N-X(C) and reserved electrons for TCE dechlorination. In addition to lowering H-2 production, S-N(C)-mZVI(bm) dechlorinated TCE to less reduced products (e.g., acetylene), contributing to the material's higher epsilon(e) 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.
