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.
J Hazard Mater. 2021 Jun 15;412:125246. doi: 10.1016/j.jhazmat.2021.125246. Epub 2021 Jan 26.
Transformation of chloro-organic compounds by nFe(0) has been studied extensively, but limited study exists on the transformation and fate of nFe(0) during the dechlorination of chloro-organics even though such knowledge is important in predicting its surface chemistry, particularly, toxicity in the environment. In this study, the nFe(0) core became hollowed, collapsed and gradually corroded into poorly crystallized ferrihydrite (FeO(OH)) at the pristine reaction time, which later gave rise to lath-like lepidocrocite (γ-FeOOH), acicular goethite (α-FeOOH) and cubic magnetite (FeO) by the end of the reaction time (120 min). Also, dechlorination of 2,4-DCP into 2-CP, 4-CP and phenol was achieved within 120 min. The rapid dechlorination of 2,4-DCP and transformation of nFe(0) could not be achieved significantly without doping Ni on nFe(0) and supporting on attapulgite. The schematic representation of the transformation and compositional evolution of nFe(0) in A-nFe/Ni was proposed. These findings are critical in understanding the compositional evolution and the fate of nFe(0) upon reaction with chloro-organics and can provide guidance for more efficient uses of the nFe(0) reactivity towards the target contaminants in groundwater remediation.
零价铁（nFe(0)）转化氯代有机化合物的研究已经很广泛，但对于氯代有机物脱氯过程中 nFe(0)的转化和归宿的研究却很有限，尽管这些知识对于预测其表面化学性质，尤其是在环境中的毒性非常重要。在本研究中，nFe(0)的核心在初始反应时间内变成空心、塌陷并逐渐腐蚀成结晶不良的水铁矿（FeO(OH)），随后在反应结束时（120 分钟）生成片状纤铁矿（γ-FeOOH）、针状针铁矿（α-FeOOH）和立方磁铁矿（FeO）。此外，2,4-DCP 在 120 分钟内脱氯生成 2-CP、4-CP 和苯酚。如果不在 nFe(0)上掺杂 Ni 并在凹凸棒土上进行支撑，2,4-DCP 的快速脱氯和 nFe(0)的转化就无法显著实现。提出了 A-nFe/Ni 中 nFe(0)的转化和组成演变的示意图。这些发现对于理解 nFe(0)与氯代有机物反应时的组成演变和归宿至关重要，并可为更有效地利用 nFe(0)对地下水修复中目标污染物的反应性提供指导。
