Mechanistic role of nitrate anion in TCE dechlorination by ball milled ZVI and sulfidated ZVI: Experimental investigation and theoretical analysis
| Autor: | Xiaojiang Qiu, Li Gong, Yawei Gu, Feng He, Jiawei Zhao, Jianlong Qi, Neng Lv |
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| Rok vydání: | 2021 |
| Předmět: |
021110 strategic
defence & security studies Environmental Engineering Trichloroethylene Chemistry Health Toxicology and Mutagenesis Kinetics Groundwater remediation 0211 other engineering and technologies Sulfidation Nitrate anion 02 engineering and technology 010501 environmental sciences 01 natural sciences Pollution chemistry.chemical_compound Chemical engineering Environmental Chemistry Waste Management and Disposal 0105 earth and related environmental sciences |
| Zdroj: | Journal of Hazardous Materials. 403:123844 |
| ISSN: | 0304-3894 |
| DOI: | 10.1016/j.jhazmat.2020.123844 |
| Popis: | Mechanistic role of NO3− in trichloroethylene (TCE) dechlorination by ball milled, micro-scale sulfidated and unsulfidated ZVI (e.g., S-mZVIbm and mZVIbm) was explored through experiments and density functional theory (DFT) calculations. Sulfidation inhibited NO3− reduction by mZVIbm as S weakened its interaction with NO3−. mZVIbm reduced NO3− within 2 h. This just resulted in a short-term electron competition during the dechlorination process by mZVIbm and hardly affected its sluggish dechlorination kinetics (complete TCE dechlorination in 11 d). On the contrary, NO3− suppressed TCE dechlorination by S-mZVIbm. This was attributed to that inhibited NO3− reduction by S-mZVIbm (40 % reduction in 6 h) induced continuous electron competition with TCE during the time span of its dechlorination by S-mZVIbm. NO3− reduction was also observed to facilitate formation/crystallization of Fe3O4 on both ZVI particles, promoting dechlorination by mZVIbm after 4 d while not taking effect to the S-mZVIbm/TCE system, as its dechlorination time was too short for the surface of S-mZVIbm to transform. This observation has important implication on groundwater remediation by ZVI or sulfidated ZVI PRBs under a scenario of upgradient anthropogenic release of NO3−. |
| Databáze: | OpenAIRE |
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