Work

Metal-ion-controlled sulfate reduction by sulfate-reducing bacteria under reaction equilibrium constraints

Year: 2026

Type: article

Abstract: Treatment of heavy metal-contaminated groundwater using sulfate-reducing bacteria (SRB) includes two subsequent reactions: SRB-mediated sulfate (SO 4 2- ) reduction to sulfide (S 2- ) and the association of S 2- with metal ions to form poorly soluble metal sulfides. Although the potential factors affecting the biological activity of SRB have been largely explored in previous studies, the influence of S 2- abundance in the system has never been systematically evaluated from the perspective of the overall reaction equilibrium. Here, the effect of co-existing metal ion concentrations—which control the residual S 2- concentration in the system—on sulfate reduction was estimated through a series of batch experiments. Contaminated groundwater collected from a currently operating smelter was used, and a mixture of peat and calcite was employed as SRB carbon sources. Batch experiments were conducted for up to 20 days under controlled anaerobic conditions, in the presence of heavy metals at concentrations ranging 6.89–128.81 mM. SO 4 2- reduction efficiencies reached approximately 72 % in the presence of Zn 2+ at their highest concentrations. The experimental results clarified that sulfate reduction might be facilitated under the condition that the residual S 2- could be continuously depleted by co-existing metal ions, indicating that the overall reaction efficiency is controlled by the reaction equilibrium. The current findings could provide critical insights for estimating the period and overall efficacy of remedial operation against heavy-metal-contaminated groundwater using SRB. • SRB-mediated sulfate reduction was evaluated from a reaction equilibrium view. • Co-existing metal ions facilitated sulfate reduction by scavenging sulfide. • SO₄²⁻ reduction rate decreased as metal ions depleted from the system. • Findings guide SRB-based remediation design for metal-contaminated groundwater. • About 72 % sulfate was reduced under high metal conditions, compared to 40 % otherwise

Source: Journal of environmental chemical engineering

DOI: 10.1016/j.jece.2026.121389

Authors: Su Hyeon Song, Sang Hyun Kim, Jaesang Lee, Jaeshik Chung, Seunghak Lee

Institutions: Korea University, Korea Institute of Science and Technology, Korea University of Science and Technology

Language: English

Topic: Mine drainage and remediation techniques

Subfield: Environmental Chemistry

Field: Environmental Science

Domain: Physical Sciences

SDG: Clean water and sanitation

Open Access status: hybrid

Estimated APC paid: $3,350