The fate of arsenic during the crystallization process of FeIII oxyhydroxides: Effect of reaction media, pH value, and Fe/As molar ratio under relatively low arsenic loading

Danni Zhang; Yuting Jin; Yumeng Wang; Shaofeng Wang; Fan Xiao; Ying Wang; Duo Wang; Dake Xu; Fuhui Wang; Yongfeng Jia

doi:10.1016/j.scitotenv.2023.167427

The fate of arsenic during the crystallization process of Fe^III oxyhydroxides: Effect of reaction media, pH value, and Fe/As molar ratio under relatively low arsenic loading

Sci Total Environ. 2023 Dec 15:904:167427. doi: 10.1016/j.scitotenv.2023.167427. Epub 2023 Sep 27.

Authors

Danni Zhang¹, Yuting Jin², Yumeng Wang³, Shaofeng Wang⁴, Fan Xiao⁵, Ying Wang⁶, Duo Wang⁷, Dake Xu², Fuhui Wang², Yongfeng Jia⁸

Affiliations

¹ Shenyang National Laboratory for Materials Science, Northeastern University, Shenyang 110819, China; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
² Shenyang National Laboratory for Materials Science, Northeastern University, Shenyang 110819, China.
³ Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; College of Energy and Power, Shenyang Institute of Engineering, Shenyang 110136, China.
⁴ Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China. Electronic address: swang@dlut.edu.cn.
⁵ Shanxi Academy of Ecological Environmental Planning and Technology, Taiyuan 030002, China.
⁶ College of Ecology and Environment, NingXia University, Yinchuan 750021, China.
⁷ Liaoning Provincial Institute of Metrology, Shenyang 110004, China.
⁸ Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.

PMID: 37774868
DOI: 10.1016/j.scitotenv.2023.167427

Abstract

Understanding the nature of arsenic (As) adsorbed on Fe^III oxyhydroxides, and the subsequent behavior of As during the crystallization process, is critical to predicting its fate in a range of natural and engineered settings. In this work, As adsorbed on Fe^III oxyhydroxides formed in the different reaction media at different pH values were characterized with X-ray diffraction (XRD), Raman spectra, transmission electron microscopy (TEM), and extended X-ray absorption fine structure spectroscopy (EXAFS) to determine how As is redistributed during the crystallization process. Results showed that at pH 12, a quarter of the added As was still left in the liquid phase with the formation of goethite and hematite as the major and minor product. The concentration of As was found to be the lowest at pH 4 which is independent of the reaction media, indicating the importance of pH value in the crystallization process of the As adsorbed Fe^III oxyhydroxides. Under acidic conditions, sulfate and chloride media favored the formation of goethite and hematite, respectively. Arsenic can indeed be incorporated into the structure of the formed goethite at pH 4. The morphology of the formed products changed to rhombus-like particles if both goethite and hematite appeared as the later as the dominant product.

Keywords: Arsenic; Crystallization; Goethite; Hematite; Reaction media.