Interactions between magnetite and humic substances: redox reactions and dissolution processes.

摘要: Humic substances (HS) are redox-active compounds that ubiquitous in the environment and can serve as electron shuttles during microbial Fe(III) reduction thus reducing a variety of minerals. However, not much is known about redox reactions between HS mixed-valent mineral magnetite (Fe3O4) potentially lead to changes Fe(II)/Fe(III) stoichiometry even dissolve magnetite. To address this knowledge gap, we incubated non-reduced (native) reduced with four types varied particle size solid-phase stoichiometry. We followed dissolved Fe(II) concentrations over time quantify Magnetite dissolution processes depending on initial properties. The interaction biogenic resulted solid mineral, well an overall In contrast, slight oxidation no was observed when native interacted 500 nm This variability solubility accepting donating capacity different likely effect differences their potential correlated stoichiometry, size, crystallinity. Our study suggests play important role for Fe speciation within minerals such thereby influence reactivity these biogeochemical cycling. Furthermore, also have fate other elements bound surface