Acid mine drainage (AMD) containing arsenic produced during coal mining is a global environmental problem. However, the coupled driving process of the key element Fe and the associated element As in the AMD environment has received little attention. Therefore, in this study, we investigated the A. ferrooxidans-mediated ferrous iron–arsenic interaction in a simulated AMD system. We reveal that in As-rich AMD the co-existing element As can regulate the metabolic activity of A. ferrooxidans to accelerate the oxidation of Fe^2 + and the subsequent formation of Fe³⁺ minerals, thereby altering the pH and ORP of the system. XRD, SEM, and XPS analyses showed that the synthesized Fe mineral mainly consisted of As-containing schwertmannite (Sch). As in an AMD system could be efficiently removed (98.7 % after 72 h) through the formation of Fe minerals, thereby reducing its own environmental risk. SO₄^2- plays an important role in As precipitation on the surface and in crystal tunnels of Sch. As-containing Sch is not only beneficial for the precipitation of As, but also for long-term reduction in As toxicity in AMD systems. Our results provide new insight for evaluating the fates of Fe and As, and the environmental and ecological risks of As in AMD produced from natural coal mines.

中文翻译：

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生物铁矿物的形成及其在酸性矿山排水环境中与亚铁耦合驱动的砷的命运


煤炭开采过程中产生的含砷的酸性矿井排水 （AMD） 是一个全球性的环境问题。然而，在 AMD 环境中，关键元素 Fe 和相关元素 As 的耦合驱动过程很少受到关注。因此，在这项研究中，我们研究了模拟 AMD 系统中 A. ferrooxidans 介导的亚铁-砷相互作用。我们揭示了在富含砷的 AMD 中，共存元素 As 可以调节 A. ferrooxidans 的代谢活性，以加速 Fe 的氧化 ²⁺ 和随后的 Fe ³⁺ 矿物的形成，从而改变系统的 pH 值和 ORP。XRD、SEM 和 XPS 分析表明，合成的 Fe 矿物主要由含 As的 schwertmannite （Sch） 组成。与 AMD 系统一样，可以通过形成 Fe 矿物有效地去除（72 小时后 98.7%），从而降低其自身的环境风险。 ₄ SO 在 Sch 表面和晶体隧道中的 As 沉淀 ^2- 中起着重要作用。含 As 的 Sch 不仅有利于 As 的沉淀，而且有利于长期降低 AMD 系统中 As 的毒性。我们的结果为评估天然煤矿生产的 AMD 中 Fe 和 As 的命运以及 As 的环境和生态风险提供了新的见解。