Oxidation and incorporation of adsorbed antimonite during iron(II)-catalyzed recrystallization of ferrihydrite

Xiuling Yin; Guoqing Zhang; Rui Su; Xiangfeng Zeng; Zelong Yan; Danni Zhang; Xu Ma; Lei Lei; Jinru Lin; Shaofeng Wang; Yongfeng Jia

doi:10.1016/j.scitotenv.2021.146424

Oxidation and incorporation of adsorbed antimonite during iron(II)-catalyzed recrystallization of ferrihydrite

Sci Total Environ. 2021 Jul 15:778:146424. doi: 10.1016/j.scitotenv.2021.146424. Epub 2021 Mar 13.

Authors

Xiuling Yin¹, Guoqing Zhang², Rui Su¹, Xiangfeng Zeng³, Zelong Yan⁴, Danni Zhang³, Xu Ma⁴, Lei Lei³, Jinru Lin³, Shaofeng Wang⁵, Yongfeng Jia³

Affiliations

¹ Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
² Key Laboratory for Yellow River and Huai River Water Environmental and Pollution Control, Ministry of Education, School of Environment, Henan Normal University, Xinxiang 453007, China.
³ Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
⁴ Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
⁵ Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China. Electronic address: wangshaofeng@iae.ac.cn.

PMID: 34030383
DOI: 10.1016/j.scitotenv.2021.146424

Abstract

The toxicity and mobility of antimony (Sb) are strongly influenced by the redox transformation of widely spread 2-line ferrihydrite (Fh) in natural soils and sediments. This study investigated the transformation and redistribution of adsorbed antimonite (Sb(III)) during Fe(II)-catalyzed recrystallization of Fh under anaerobic conditions. X-ray diffraction (XRD), transmission electron microscopy (TEM), and synchrotron based X-ray absorption spectroscopy (XAS) were utilized to characterize the mineralogy and morphology of generated minerals as well as the speciation of Sb and Fe. Chemical analysis and Sb L_III-edge XANES spectra demonstrated that a great part of Sb(III) (80%-90%) was oxidized to Sb(V) by reactive oxygen species (ROS) during the Fe(II)-catalyzed transformation of Fh. Chemical extraction results showed that the mobility of Sb was significantly reduced with 50%-70% of initially adsorbed Sb(III) transformed to phosphate-unextractable phase. Antimony K-edge EXAFS analysis showed the SbO₆ octahedra were incorporated into secondary minerals by substituting the Fe atoms. Our findings shed new light on the understanding of the geochemical behavior of Sb(III) under anoxic conditions.

Keywords: Antimony; Fe(II)-catalyzed recrystallization; Ferrihydrite; Incorporation; Oxidation.