State Key Laboratory of Organic Geochemistry, Guangdong Provincial Key Laboratory of Environmental Protection and Resources and Utilization, Guangdong-Hong Kong-Maco Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
Department of Environmental Sciences, Rutgers, The State University of New Jersey, 14 College Farm Road, New Brunswick, NJ 08901, USA.
Environ Sci Process Impacts. 2021 Feb 4;23(1):86-97. doi: 10.1039/d0em00375a.
Modification of nanoscale zero-valent iron (nZVI) with reducing sulfur compounds has proven to improve the reactivity of nZVI towards recalcitrant halogenated organic contaminants. In this study, we develop a novel method for the preparation of sulfidated nZVI (S-nZVI) with S0 (a low cost and available reducing sulfur agent) dissolved in ethanol under mild conditions and apply it for the transformation of tetrabromobisphenol A (TBBPA), a potential persistent organic pollutant. Surface analysis shows that S0 dissolved in ethanol has been successfully doped into nZVI via a reaction with Fe0 to form a relatively homogeneous layer of FeS/FeS2 on the nZVI surface. The H2 production test and the electrochemical analysis show that the FeS/FeS2 layer not only slows the H2 evolution reaction but also enhances the electron transfer. Debromination kinetics indicate that the resulting S-nZVI with a S/Fe ratio of 0.015-0.05 possesses higher debromination activity for TBBPA and its debromination products (i.e., tri-BBPA, di-BBPA, mono-BBPA and BPA) in comparison with nZVI. Among them, S-nZVI at a S/Fe of 0.025 (S-nZVIS-0.025) has the greatest debromination rate constant (kobs) of 1.19 ± 0.071 h-1 for TBBPA. It debrominates TBBPA at a faster rate than other conventional S-nZVI made from Na2S and Na2S2O4 and has been successfully applied in the treatment of TBBPA-spiked environmental water samples (including river water, groundwater, and tap water). The results suggest that the modification of nZVI with S0 dissolved in ethanol is a simple, safe, inexpensive, and effective sulfidation technique, which can be applied for the large-scale production of S-nZVI for treating contaminated water.
用还原硫化合物对纳米零价铁（nZVI）进行改性已被证明可以提高 nZVI 对难处理卤代有机污染物的反应活性。在这项研究中，我们开发了一种在温和条件下用溶于乙醇的 S0（一种低成本且易得的还原硫试剂）制备硫化纳米零价铁（S-nZVI）的新方法，并将其应用于四溴双酚 A（TBBPA）的转化，TBBPA 是一种潜在的持久性有机污染物。表面分析表明，S0 溶于乙醇后通过与 Fe0 反应成功地掺杂到 nZVI 中，在 nZVI 表面形成了相对均匀的 FeS/FeS2 层。氢气生成测试和电化学分析表明，FeS/FeS2 层不仅减缓了氢气的析出反应，而且增强了电子转移。脱溴动力学表明，具有 S/Fe 比为 0.015-0.05 的所得 S-nZVI 对 TBBPA 及其脱溴产物（即三-BBPA、二-BBPA、单-BBPA 和 BPA）具有更高的脱溴活性，优于 nZVI。其中，S/Fe 比为 0.025 的 S-nZVI（S-nZVIS-0.025）对 TBBPA 的最大脱溴速率常数（kobs）为 1.19±0.071 h-1。它比其他由 Na2S 和 Na2S2O4 制备的常规 S-nZVI 更快地脱溴 TBBPA，并已成功应用于处理 TBBPA 污染的环境水样（包括河水、地下水和自来水）。结果表明，用溶于乙醇的 S0 对 nZVI 进行改性是一种简单、安全、廉价且有效的硫化技术，可用于大规模生产 S-nZVI 以处理受污染的水。
