ISSN 1000-3665 CN 11-2202/P
    唐雅宁,王兴华,王英男,等. 缺氧酸性条件下三价铁对锑释放的作用机制[J]. 水文地质工程地质,2023,50(6): 175-183. DOI: 10.16030/j.cnki.issn.1000-3665.202212026
    引用本文: 唐雅宁,王兴华,王英男,等. 缺氧酸性条件下三价铁对锑释放的作用机制[J]. 水文地质工程地质,2023,50(6): 175-183. DOI: 10.16030/j.cnki.issn.1000-3665.202212026
    TANG Yaning, WANG Xinghua, WANG Yingnan, et al. Mechanism of action of Fe(III) on antimony release under anoxic acidic conditions[J]. Hydrogeology & Engineering Geology, 2023, 50(6): 175-183. DOI: 10.16030/j.cnki.issn.1000-3665.202212026
    Citation: TANG Yaning, WANG Xinghua, WANG Yingnan, et al. Mechanism of action of Fe(III) on antimony release under anoxic acidic conditions[J]. Hydrogeology & Engineering Geology, 2023, 50(6): 175-183. DOI: 10.16030/j.cnki.issn.1000-3665.202212026

    缺氧酸性条件下三价铁对锑释放的作用机制

    Mechanism of action of Fe(III) on antimony release under anoxic acidic conditions

    • 摘要: 辉锑矿(Sb2S3)的氧化溶解是控制锑(Sb)从岩矿中释放进入水土环境并影响其迁移转化的首要过程。酸性矿山废水中的三价铁Fe(III)是矿区环境中广泛存在的天然氧化剂,然而Fe(III)对Sb2S3的氧化溶解与Sb的释放作用机制尚不明确。通过模拟黑暗缺氧酸性的矿山地下水环境,开展Fe(III)浓度与Sb2S3表面积比值(I)控制的Sb2S3氧化溶解动力学实验,结合S-Sb-Fe氧化还原作用产物的溶解态组成与固相表征手段,揭示Fe(III)对Sb释放的作用机制。结果显示:Fe(III)作用下Sb2S3的氧化溶解是一个产酸的过程,I值越大,Fe(III)对Sb释放的促进作用越明显。缺氧条件下,Fe(III)与Sb2S3发生氧化还原作用,主要产物是五价锑Sb(V)、硫单质S(0)和二价铁Fe(Ⅱ),反应后矿物表面有S(0)和Fe2O3检出,阻碍了Sb2S3氧化溶解反应的持续进行。 I值一定时,低浓度的Fe(III)和溶解氧(DO)质量浓度的增加均会减少矿物表面S(0)的附着量,促进Sb释放量的增加;溶液中的Cl通过配位络合效应会促进Sb2S3的溶解释放。缺氧酸性条件下Fe(III)与Sb2S3的作用控制着Sb的释放。研究结果可为矿山闭坑后地下水Sb污染防治提供重要的理论依据。

       

      Abstract: Oxidative dissolution of stibnite (Sb2S3) is the primary process that controls the release of antimony (Sb) from rock and ore into the soil and water environment and affects its transport and transformation. Fe(III) in acid mine wastewater is a widespread natural oxidant in the mine environment. However, the role of Fe(III) on the oxidative dissolution of Sb2S3 and Sb release is unknown. By simulating a dark anoxic and acidic mine groundwater environment, this study conducted Fe(III) concentration to Sb2S3 surface area ratio (I) controlled Sb2S3 oxidative dissolution kinetics experiments, and combined the dissolved state composition and solid phase characterization means of S-Sb-Fe redox products to reveal the mechanism of Fe(III) action on Sb release. The results show that the oxidative dissolution of Sb2S3 under the action of Fe(III) is an acid-producing process, and the larger the I value is, the more obvious the promotion effect of Fe(III) on Sb release. Under anoxic conditions, Fe(III) undergoes redox with Sb2S3, and the main products are Sb(V), S(0) and Fe(II). After the reaction, S(0) and Fe2O3 were detected on the mineral surface, which hindered the continuation of the oxidative dissolution reaction of Sb2S3. At a certain value of I, both the low concentration of Fe(III) and the increase of dissolved oxygen (DO) will reduce the attachment of S(0) on the mineral surface and promote the increase of Sb release; the Cl in solution will promote the dissolution release of Sb2S3 through the coordination complexation effect. The interaction between Fe(III) and Sb2S3 under anoxic acidic conditions controls the release of Sb, which can provide an important theoretical basis for prevention and control of groundwater Sb contamination after mine pit closure.

       

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