Work

Antimonate reduction and immobilization driven by pyrite and woodchips-based abiotic and biotic processes

Year: 2026

Type: article

Abstract: Antimony (Sb) pollution in aquatic environments poses severe threats to ecological safety and human health due to its high toxicity. Four reaction systems were constructed in this study, including a pyrite abiotic reactor (PAR), a pyrite-woodchips abiotic reactor (PWAR), a pyrite biotic reactor (PBR), and a pyrite-woodchips biotic reactor (PWBR), to systematically investigate the Sb(V) removal performance in various systems. The results showed that PAR achieved limited Sb(V) removal efficiencies of 56.4%–57.6% at a hydraulic retention time (HRT) of 12 h with an initial Sb(V) of 10 mg/L. In contrast, microbial inoculation improved Sb remediation performance, and woodchips amendment further optimized the reaction microenvironment. The PWBR obtained Sb(V) and total Sb removal efficiencies of >90% in the first 20 days, and final stabled at 69.3% and 64.5% with HRT = 12, respectively. SEM and XPS analysis identified the generation of Sb-O, Sb-S, and Fe-O-Sb precipitation. Woodchips acted as a slow-release carbon source and biofilm carrier, fueling microbial tricarboxylic acid (TCA) cycle metabolism and stimulating the proliferation of functional bacteria, including Candidatus Competibacter , Ignavibacterium , Desulfobacterium , Geobacter , and Shewanella . Functional gene prediction confirmed that woodchips significantly upregulated genes involved in carbon metabolism, sulfate reduction, and iron transport, accelerating the coupled Fe 2+ /Fe 3+ and S cycles. Abiotic Sb removal mainly depended on pyrite-mediated chemical reduction and adsorption, while biotic processes further strengthened pyrite dissolution, electron donor supply, and Sb-S precipitate formation. This study provides a reliable theoretical basis and technical reference for efficient Sb immobilization in the presence of Fe, S and C.

Source: Journal of Water Process Engineering

DOI: 10.1016/j.jwpe.2026.111017