Abstract：
Applying organic fertilizer is the main way to enhance soil fertility through the interfacial reaction between mineral and dissolved organic matter (DOM). However, the interfacial reaction between minerals and DOM may influence antimony(V) (Sb(V)) mobility in agricultural soils around antimony mines. In our study the ferrihydrite (Fh) was chosen as a representative mineral, to reveal the effect of its interaction with chicken manure organic fertilizer (CM-DOM) with Fh on Sb(V) migration. In this study, we investigated different organic matter molecular weights and C/Fe molar ratios. Our findings indicated that the addition of CM-DOM decreased the adsorption of Sb(V) by Fh and promoted the re-release of Sb(V) adsorbed on Fh. This effect was enhanced by increasing the C/Fe molar ratio. Fh mainly affects its interaction with Sb(V) through electrostatic gravitational interaction and ligand exchange, but the presence of CM-DOM weakens the electrostatic interaction between Fh and Sb(V) as well as competes with Sb(V) for the hydroxyl reactive site on Fh surface. In addition, the smaller molecular weight fraction (<10 kDa) of CM-DOM has higher aromaticity and hydrophobicity, which potentially leads to more intense competition with Sb(V) for the reaction sites on Fh. Therefore, the application of organic fertilizer may promote Sb(V) migration, posing significant risks to soil ecosystems and human health, which should be a concern in field soil cultivation.
摘要：
施用有机肥是通过矿物质与溶解性有机质（DOM）之间的界面反应提高土壤肥力的主要途径。然而,矿物与DOM之间的界面反应可能会影响锑矿周围农业土壤中锑（V）（Sb（V））的迁移率。在我们的研究中，选择水铁矿（Fh）作为代表性矿物，揭示其与Fh鸡粪有机肥（CM-DOM）相互作用对Sb（V）迁移的影响。在这项研究中,我们研究了不同的有机物分子量和C/Fe摩尔比。我们的发现表明，CM-DOM的添加降低了Fh对Sb（V）的吸附，并促进了Fh上Sb（V）的再释放。该效果通过增加C/Fe摩尔比而增强。Fh主要通过静电重力相互作用和配体交换影响其与Sb（V）的相互作用，但是CM-DOM的存在削弱了Fh与Sb（V）之间的静电相互作用，并与Sb（V）竞争Fh表面上的羟基反应位点。此外,分子量较小(<10kDa)的CM-DOM具有较高的芳香性和疏水性,这可能导致与Sb（V）对Fh上反应位点的更激烈竞争。因此,有机肥的施用可以促进Sb(V)的迁移,对土壤生态系统和人类健康构成重大风险，这在田间土壤栽培中应该引起关注。
