A molecular level understanding of antimony immobilization mechanism on goethite by the combination of X-ray absorption spectroscopy and density functional theory calculations

Qian Sun; Cun Liu; Tingting Fan; Hu Cheng; Peixin Cui; Xueyuan Gu; Lina Chen; Syed Tahir Ata-Ul-Karim; Dongmei Zhou; Yujun Wang

doi:10.1016/j.scitotenv.2022.161294

A molecular level understanding of antimony immobilization mechanism on goethite by the combination of X-ray absorption spectroscopy and density functional theory calculations

Sci Total Environ. 2023 Mar 20:865:161294. doi: 10.1016/j.scitotenv.2022.161294. Epub 2022 Dec 30.

Authors

Qian Sun¹, Cun Liu², Tingting Fan³, Hu Cheng⁴, Peixin Cui², Xueyuan Gu⁵, Lina Chen⁶, Syed Tahir Ata-Ul-Karim⁷, Dongmei Zhou⁵, Yujun Wang⁸

Affiliations

¹ College of Agricultural Sciences and Engineering, Hohai University, Nanjing 210098, China; Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, the Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, the Chinese Academy of Sciences, Nanjing 210008, China.
³ Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection of the People's Republic of China, Nanjing 210008, China.
⁴ College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China.
⁵ State Key Laboratory of Pollution Control and Resource Research, School of Environment, Nanjing University, Nanjing 210008, China.
⁶ College of Agricultural Sciences and Engineering, Hohai University, Nanjing 210098, China.
⁷ Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
⁸ Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, the Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: yjwang@issas.ac.cn.

PMID: 36592910
DOI: 10.1016/j.scitotenv.2022.161294

Abstract

A molecular level understanding of antimony (Sb) immobilization mechanism on Fe oxides is required to clarify the fate of Sb in the soil. In this study, macroscopic sorption experiments, combined with extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional theory (DFT), were utilized to explore the interaction between Sb and goethite. The ion strength has no effect on Sb sorption on goethite, indicating the inner-sphere complex Sb formed on goethite. Goethite has the higher sorption potential to Sb(III) than Sb(V), consistent with the higher thermodynamic stability of the geometry for Sb(III) formed on goethite than Sb(V) revealed by DFT calculations. By comparing the Sb-Fe distances obtained by EXAFS spectroscopy and DFT, eight kinds of Sb(III) surface complexes and nine kinds of Sb(V) surface complexes were considered to be the possible geometries Sb formed on different crystal planes of goethite, including monodentate mononuclear, bidentate mononuclear, bidentate binuclear, tridentate mononuclear, tridentate binuclear, tridentate four-nuclear complexes. The structural and energetic details of these filtered geometries provide comprehensive information on Sb immobilization mechanism on goethite, helpful in clarifying the fate of Sb in soils.

Keywords: Antimony; DFT; EXAFS; Goethite; Immobilization.