Microbial processes suppress antimony release during stibnite weathering under suboxic condition

IF 3.6 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Chemical Geology Pub Date : 2025-09-02 DOI:10.1016/j.chemgeo.2025.123029

Ting Lu , Li Shao , Aiwen Wu , Zengping Ning , Tangfu Xiao , Enzong Xiao

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Abstract

This study investigates the geochemical behavior of antimony (Sb) during the suboxic weathering of stibnite through both chemical and microbial processes. Our study revealed that microbial process suppresses the stibnite dissolution compared to chemical processes, contrasting with established models of Sb geochemical behaviors in oxic environments. In early stages, chemical weathering group (AS) and a microbial weathering group (BS) achieved comparable aqueous Sb concentrations (∼0.2 mM), yet through divergent mechanisms: AS formed passivating sénarmontite (Sb₂O₃) coatings via rapid surface oxidation, while BS established biofilms that physically decoupled Sb release from oxidative dissolution. In late stages, a paradigm shift occurred: AS exhibited 3-fold higher aqueous Sb (∼0.6 mM) compared to BS, with >95 % Sb(V) due to Fe(II)/Fe(III) redox cycling. This process enhanced Sb(III) oxidation kinetics and promoted Sb(V)-Fe(III) oxyhydroxide coprecipitation, confirmed by XPS spectra. In contrast, BS maintained stable Sb levels (0.2 mM) with limited Sb(V) accumulation (58 %). Microbial consortia sequestered Fe(II) through enzymatic reduction, disrupting iron redox cycling and reducing Sb release. This “biogenic passivation” mechanism stabilized Sb, differing from oxic systems where biofilms typically accelerate Sb(III) oxidation. The findings improve predictions of Sb mobility in suboxic environments and suggest biofilm-mediated strategies for Sb pollution control.

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在缺氧条件下，微生物作用抑制辉锑矿风化过程中锑的释放

研究了锑在辉锑矿亚氧风化过程中的化学风化和微生物风化的地球化学行为。我们的研究表明，与化学过程相比，微生物过程抑制了辉锑矿的溶解，并与已建立的含氧环境中锑的地球化学行为模型进行了对比。在早期阶段，化学风化组（AS）和微生物风化组（BS）获得了相当的水溶液Sb浓度（~ 0.2 mM），但通过不同的机制：AS通过快速表面氧化形成钝化ssamumontite （Sb₂O₃）涂层，而BS建立了生物膜，物理上使Sb从氧化溶解中释放出来。在后期，发生了范式转变：AS表现出比BS高3倍的水溶液Sb(~ 0.6 mM)，其中>； 95% Sb(V)是由于Fe(II)/Fe（III）氧化还原循环。XPS光谱证实，该工艺增强了Sb（III）的氧化动力学，促进了Sb(V)-Fe（III）的氢氧共沉淀。相比之下，BS保持稳定的Sb水平（0.2 mM）， Sb(V)积累有限（58%）。微生物群落通过酶还原、破坏铁氧化还原循环和减少Sb释放来隔离铁（II）。这种“生物钝化”机制稳定了Sb，不同于生物膜通常加速Sb（III）氧化的氧化系统。研究结果改善了对锑在低氧环境中迁移的预测，并提出了生物膜介导的锑污染控制策略。

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来源期刊

Chemical Geology 地学-地球化学与地球物理

CiteScore

7.20

自引率

10.30%

发文量

374

审稿时长

3.6 months

期刊介绍： Chemical Geology is an international journal that publishes original research papers on isotopic and elemental geochemistry, geochronology and cosmochemistry. The Journal focuses on chemical processes in igneous, metamorphic, and sedimentary petrology, low- and high-temperature aqueous solutions, biogeochemistry, the environment and cosmochemistry. Papers that are field, experimentally, or computationally based are appropriate if they are of broad international interest. The Journal generally does not publish papers that are primarily of regional or local interest, or which are primarily focused on remediation and applied geochemistry. The Journal also welcomes innovative papers dealing with significant analytical advances that are of wide interest in the community and extend significantly beyond the scope of what would be included in the methods section of a standard research paper.