Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Nanjing, 210008, China.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Jiangsu Engineering Laboratory for Soil and Groundwater Remediation of Contaminated Sites, Nanjing, 210008, China.
Chemosphere. 2023 Apr;321:138111. doi: 10.1016/j.chemosphere.2023.138111. Epub 2023 Feb 11.
Iron sulfides have attracted growing concern in heterogeneous Fenton reaction. However, the structure of iron sulfides is different from that of iron oxides and how the structures affect the activation property of hydrogen peroxide (HO) remains unclear. This study investigated benzene removal through the activation of HO by the synthesized magnetite (FeO) and greigite (FeS). The structures of FeO and FeS were characterized by XRD and EPR, the electron transfer properties of FeO and FeS were analyzed by electrochemical workstation, XPS and DFT. It is revealed that the effective benzene removal rate of 88.86％ in the FeS/HO was achieved, which compared to 15.58％ obtainable from the FeO/HO, with the apparent rate constant in the FeS/HO being approximately 65 times over that in the FeO/HO. The better HO activation by FeS was attributed to the significant roles of S (-II) and S vacancies in regulating the dissolution of ferrous iron ions, thus generating abundant free •OH radical. In addition, surface bounded ferrous iron of FeS could transfer more electrons to HO and O to generate more surface bounded •OH and •O. This study revealed the combined action of dissolved and surface bounded ferrous iron of greigite on HO activation, and provides an efficient heterogeneous HO activator for the remediation of organic contaminants in groundwater.
铁硫化物在非均相芬顿反应中引起了越来越多的关注。然而，铁硫化物的结构不同于铁氧化物，其结构如何影响过氧化氢（HO）的活化性能仍不清楚。本研究通过合成的磁铁矿（FeO）和陨铁（FeS）来研究通过 HO 去除苯。通过 XRD 和 EPR 对 FeO 和 FeS 的结构进行了表征，通过电化学工作站、XPS 和 DFT 分析了 FeO 和 FeS 的电子转移特性。结果表明，在 FeS/HO 中实现了有效的 88.86％的苯去除率，与 FeO/HO 中可获得的 15.58％相比，FeS/HO 中的表观速率常数约为 FeO/HO 的 65 倍。FeS 对 HO 的更好的活化归因于 S(-II)和 S 空位在调节二价铁离子溶解方面的重要作用，从而产生丰富的游离•OH 自由基。此外，FeS 的表面结合的二价铁可以将更多的电子转移到 HO 和 O 上，从而产生更多的表面结合的•OH 和•O。本研究揭示了陨铁中溶解和表面结合的二价铁对 HO 活化的联合作用，为地下水有机污染物的修复提供了一种有效的非均相 HO 活化剂。
