Enhanced arsenic(III) sequestration via sulfidated zero-valent iron in aerobic conditions: Adsorption and oxidation coupling processes

Haiming Cai; Xiaodong Du; Ziting Lin; Xueqin Tao; Mengyao Zou; Jingyong Liu; Lijuan Zhang; Zhi Dang; Guining Lu

doi:10.1016/j.jhazmat.2023.132190

Enhanced arsenic(III) sequestration via sulfidated zero-valent iron in aerobic conditions: Adsorption and oxidation coupling processes

J Hazard Mater. 2023 Oct 5:459:132190. doi: 10.1016/j.jhazmat.2023.132190. Epub 2023 Jul 29.

Authors

Haiming Cai¹, Xiaodong Du¹, Ziting Lin², Xueqin Tao³, Mengyao Zou⁴, Jingyong Liu², Lijuan Zhang⁵, Zhi Dang⁶, Guining Lu⁷

Affiliations

¹ School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
² School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
³ College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
⁴ College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China. Electronic address: mengyaozou@zhku.edu.cn.
⁵ School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China.
⁶ School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou 510006, China.
⁷ School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, China. Electronic address: lutao@scut.edu.cn.

PMID: 37536156
DOI: 10.1016/j.jhazmat.2023.132190

Abstract

Sulfidated zero-valent iron (S-ZVI) has shown significant potential for the removal of arsenic(III). However, little attention has been paid to the mechanism of As(III) sequestration enhancement and how the phase transformation for S-ZVI strengthens this process in aerobic conditions. In this work, sulfidated ZVI was created by ball-milling (S-ZVI^bm) and liquid-mixing (S-ZVI^lm) of ZVI with elemental sulfur(S⁰) to investigate the performance and mechanisms of As(III) sequestration in air-saturated water. Sulfidation was found to significantly enhance the As(III) removal rate constant, which was 2.8 ∼ 6.7 times (S-ZVI^bm) and 3.1 ∼ 17.1 times (S-ZVI^lm) higher than that without sulfidation. FeS was identified as the predominant sulfur species in the S-ZVI samples using S K-edge XANES spectra. The enhanced electron transfer and ZVI corrosion after sulfidation were verified via electrochemical tests. XANES and Mössbauer spectra suggested that lepidocrocite(γ-FeOOH) was the predominant corrosion product generated on the ZVI surface with the presence of oxygen, and DFT calculations further confirmed the improved performance of γ-FeOOH for As(III) sequestration. Besides, As(III) oxidation occurred dominantly on the heterogeneous surface rather than in solution, and the As(III) sequestration pathway of adsorption followed by oxidation was proposed. This study provides new insight into the enhanced As(III) sequestration by S-ZVI in aerobic conditions.

Keywords: Aerobic conditions; Arsenic(III) sequestration; Oxidation; Sulfidation; ZVI.