Cobalt regulation biocathode with sulfate-reducing bacteria for enhancing the reduction of antimony and the removal of sulfate in a microbial electrolysis cell simultaneously

Yuchen Xie; Minhui Chen; Ming Yong; Zhuyuan Wang; Hongyu Wang; Ziyin Xia; Chenxi Li; Meng Li; Lei Huang; Jia Yan; Hongguo Zhang

doi:10.1016/j.envres.2025.120955

Cobalt regulation biocathode with sulfate-reducing bacteria for enhancing the reduction of antimony and the removal of sulfate in a microbial electrolysis cell simultaneously

Environ Res. 2025 Jan 25:120955. doi: 10.1016/j.envres.2025.120955. Online ahead of print.

Authors

Yuchen Xie¹, Minhui Chen¹, Ming Yong², Zhuyuan Wang³, Hongyu Wang¹, Ziyin Xia¹, Chenxi Li¹, Meng Li⁴, Lei Huang¹, Jia Yan¹, Hongguo Zhang⁵

Affiliations

¹ School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, PR. China.
² Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia.
³ Dow Centre for Sustainable Engineering Innovation, School of Chemical Engineering, The University of Queensland St Lucia, QLD 4072, Australia.
⁴ School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, PR. China. Electronic address: mengli@gzhu.edu.cn.
⁵ School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, PR. China; Guangzhou University-Linköping University Research Center on Urban Sustainable Development, Guangzhou University, Guangzhou 510006, PR. China. Electronic address: hgzhang@gzhu.edu.cn.

PMID: 39870342
DOI: 10.1016/j.envres.2025.120955

Abstract

Antimony (Sb) contamination in water resources poses a critical environmental and health challenge globally. Sulfate reducing bacteria (SRB) are employed to reduce SO₄^2- to S^2- for removing Sb in a microbial electrolysis cell (MEC). Yet, the reduction efficiency of reducing SO₄^2- and Sb(Ⅴ) through SRB remains relatively low, and the underlying mechanism remains elusive. Herein, the MEC reactor modified with Co-based or Fe-based MOF materials was served to enhance the electron transfer between the aqueous environment and the microorganisms to enhance the operational efficiency of the bio-electrochemical system (MEC-SRB). This study highlights the central role of removal efficiency as a critical performance metric and its direct correlation with material properties and mechanisms. The results demonstrate that the ZIF-8@Co electrode significantly outperformed other materials, achieving 98.7% sulfate and 93.1% total Sb removal over multiple cycles. Electrochemical analysis revealed that the superior performance of ZIF-8@Co electrode is attributed to rapid electron transfer and low electronic impedance. The charge transfer resistance of the ZIF-8@Co group was 155 Ω, significantly lower than that of the ZIF-8@Fe group (1724 Ω) and the ZIF-8@CoFe group (427 Ω). These findings demonstrate that the material's ability to facilitate electron transfer directly governs the pollutant removal efficiency. Fluorescence analysis revealed that the ZIF-8@Co electrode supported a denser biofilm and enhanced microbial activity. Mechanistic studies confirmed that Sb(Ⅴ) was reduced and deposited as Sb₂S₃ precipitate, which was further characterized and analyzed by methods such as XRD and XPS. This research elucidates the potential and underlying mechanisms of an electrically stimulated SRB bio-electrochemical system for effective Sb-containing wastewater treatment. Our findings provide crucial insights for developing high-efficiency, sustainable remediation technologies for heavy metal contamination, with significant potential for real-world application in water treatment and environmental protection.

Keywords: Biological Cathode; Metal-Organic Frameworks; Microbial Electrolysis Cell; Sb Contamination; Sulfate Reducing Bacteria.