College of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan 430081, China; Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources, Wuhan University of Science and Technology, Wuhan 430081, China.
College of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan 430081, China; Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources, Wuhan University of Science and Technology, Wuhan 430081, China.
Sci Total Environ. 2019 Dec 20;697:133996. doi: 10.1016/j.scitotenv.2019.133996. Epub 2019 Aug 19.
Three possible dechlorination mechanisms of chloroorganics by nanoscale zero-valent iron (n-ZVI) have been proposed and widely accepted, however, the main mechanism is still controversial and not verified by experimental results. In this study, 2,4-dichlorophenol (2,4-DCP) was selected as the target pollutant and the experiments were carried out for the screening of the main mechanism of 2,4-DCP dechlorination by n-ZVI and Fe/Ni nanoparticles (n-Fe/Ni). The results indicated that >95% of 2,4-DCP could be dechlorinated to phenol by n-Fe/Ni within 120 min, while 2,4-DCP could hardly be dechlorinated by n-ZVI particles. The active hydrogen atom (H*) that transformed from H under the catalysis of Ni was responsible for >90% of 2,4-DCP dechlorination by n-Fe/Ni and <10% of the dechlorination was attributed to the direct electron transfer from ZVI. Fe was not able to dechlorinate 2,4-DCP. Correspondently, Ni in n-Fe/Ni mainly acted as a catalyst, while the acceleration of electron transfer from ZVI by Ni had a positive effect on 2,4-DCP dechlorination. The investigations on the relative importance of these three mechanisms are essential to iron-based remediation technology.
三种可能的纳米零价铁（nZVI）脱氯机制已被提出并广泛接受，但主要机制仍存在争议，尚未通过实验结果得到验证。在这项研究中，选择 2,4-二氯苯酚（2,4-DCP）作为目标污染物，通过实验筛选 nZVI 和 Fe/Ni 纳米颗粒（n-Fe/Ni）脱氯的主要机制。结果表明，n-Fe/Ni 在 120min 内可将超过 95%的 2,4-DCP 脱氯为苯酚，而 nZVI 颗粒几乎不能使 2,4-DCP 脱氯。在 Ni 催化下从 H 转化而来的活性氢原子（H*）负责 n-Fe/Ni 脱除超过 90%的 2,4-DCP，而<10%的脱氯归因于 ZVI 的直接电子转移。Fe 不能使 2,4-DCP 脱氯。相应地，n-Fe/Ni 中的 Ni 主要起催化剂的作用，而 Ni 加速 ZVI 的电子转移对 2,4-DCP 的脱氯有积极影响。对这三种机制的相对重要性的研究对于基于铁的修复技术至关重要。
