New insight into the activation mechanism of hydrogen peroxide by greigite (Fe3S4) for benzene removal: The combined action of dissolved and surface bounded ferrous iron

Cong Liang; Linbo Qian; Hangyu Li; Xinzhu Dong; Tao Zheng; Mengfang Chen

doi:10.1016/j.chemosphere.2023.138111

New insight into the activation mechanism of hydrogen peroxide by greigite (Fe₃S₄) for benzene removal: The combined action of dissolved and surface bounded ferrous iron

Chemosphere. 2023 Apr:321:138111. doi: 10.1016/j.chemosphere.2023.138111. Epub 2023 Feb 11.

Authors

Cong Liang¹, Linbo Qian², Hangyu Li¹, Xinzhu Dong¹, Tao Zheng³, Mengfang Chen⁴

Affiliations

¹ 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.
² 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. Electronic address: lbqian@issas.ac.cn.
³ School of Environmental Studies, China University of Geosciences, Wuhan, 430078, China.
⁴ 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. Electronic address: mfchen@issas.ac.cn.

PMID: 36780998
DOI: 10.1016/j.chemosphere.2023.138111

Abstract

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 (H₂O₂) remains unclear. This study investigated benzene removal through the activation of H₂O₂ by the synthesized magnetite (Fe₃O₄) and greigite (Fe₃S₄). The structures of Fe₃O₄ and Fe₃S₄ were characterized by XRD and EPR, the electron transfer properties of Fe₃O₄ and Fe₃S₄ were analyzed by electrochemical workstation, XPS and DFT. It is revealed that the effective benzene removal rate of 88.86％ in the Fe₃S₄/H₂O₂ was achieved, which compared to 15.58％ obtainable from the Fe₃O₄/H₂O₂, with the apparent rate constant in the Fe₃S₄/H₂O₂ being approximately 65 times over that in the Fe₃O₄/H₂O₂. The better H₂O₂ activation by Fe₃S₄ 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 Fe₃S₄ could transfer more electrons to H₂O₂ and O₂ to generate more surface bounded •OH and •O₂^-. This study revealed the combined action of dissolved and surface bounded ferrous iron of greigite on H₂O₂ activation, and provides an efficient heterogeneous H₂O₂ activator for the remediation of organic contaminants in groundwater.

Keywords: Benzene; Dissolved ferrous iron; Greigite; H(2)O(2); Surface bounded ferrous iron.

MeSH terms

Benzene*
Hydrogen Peroxide* / chemistry
Iron / chemistry
Oxidation-Reduction
Sulfides / chemistry

Substances

greigite
Hydrogen Peroxide
Benzene
Iron
Sulfides
ferrous sulfide