Arsenic contamination in groundwater and industrial wastewater poses a significant threat to human health and the ecosystem. Electrochemical reduction of highly mobile As(III) species into less toxic elemental arsenic (As(0)) has emerged as a promising method to effectively recover arsenic from water. In this study, a novel CuSn alloy nanowire array-modified copper foam (CuSn NAs/CF) electrode was fabricated for the direct electrochemical reduction of As(III) to As(0). The electrocatalytic reduction of As(III) was systematically investigated under various reaction conditions, including current densities, solution pH, electrolytes, and initial As(III) concentrations. The CuSn NAs/CF electrode was proven to effectively suppress the hydrogen evolution reaction and greatly enhance the electrochemical reduction of As(III). The recovery yield of As(0) on the CuSn NAs/CF electrode reached 3.67 mg/cm² at 90 min of electrolysis in a 0.1 M Na₂SO₄ at pH 11, which was 2.75 times higher than that of the Cu NAs-modified electrode. Furthermore, the as-prepared electrode also demonstrated excellent electrochemical stability and a longer service life, maintaining a recovery yield of As(0) at 2.62 mg/cm² even after 6 cycles. The reduction reaction mechanism of As(III) was ascribed to the synergistic effect of direct electrolysis and hydrogen radicals (·H) formation, as revealed by ESR and radical scavenger experimental results. This study not only provides convincing evidence for the direct electrochemical conversion of As(III) to As(0) on an innovative CuSn alloy electrode, but also offers a promising strategy to recover and reuse waste arsenic resources. This contributes to a sustainable and environmentally friendly approach to arsenic-containing wastewater treatment.

中文翻译：

---

CuSn合金电极上直接电催化还原As(III)：从砷废水中回收元素砷的绿色可持续策略


地下水和工业废水中的砷污染对人类健康和生态系统构成重大威胁。将高流动性的 As(III) 物质电化学还原为毒性较小的元素砷 (As(0)) 已成为有效从水中回收砷的有前途的方法。在这项研究中，制备了一种新型CuSn合金纳米线阵列改性泡沫铜（CuSn NAs/CF）电极，用于将As（III）直接电化学还原为As（0）。在各种反应条件下，包括电流密度、溶液 pH 值、电解质和初始 As(III) 浓度，系统地研究了 As(III) 的电催化还原。 CuSn NAs/CF电极被证明可以有效抑制析氢反应并大大增强As(III)的电化学还原。 CuSn NAs/CF 电极在 0.1 M Na ₂ SO ₄ 。 ESR和自由基清除剂实验结果揭示了As(III)的还原反应机理归因于直接电解和氢自由基(·H)形成的协同作用。这项研究不仅为创新型 CuSn 合金电极上 As(III) 直接电化学转化为 As(0) 提供了令人信服的证据，而且为回收和再利用废弃砷资源提供了一种有前景的策略。 这有助于采用可持续且环保的方法来处理含砷废水。