School of Resources, Environment and Safety Engineering, Hunan University of Science and Technology, Xiangtan 411201, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-Sen University, Guangzhou 510275, China.
School of Resources, Environment and Safety Engineering, Hunan University of Science and Technology, Xiangtan 411201, China.
J Hazard Mater. 2024 Dec 5;480:135917. doi: 10.1016/j.jhazmat.2024.135917. Epub 2024 Sep 19.
The oxidative dissolution of arsenopyrite (FeAsS) is a significant source of arsenic contamination in nature. Activated biochar (AC), a widely used environmental remediation agent, is prevalent in ecosystems and participated in various geochemical processes of arsenic and iron-containing sulfide minerals. However, the impact of AC-arsenopyrite association on reactive oxidation species (ROS) generation and its contribution to As transformation were rarely explored. Here, ROS formation and the redox conversion of As during the interaction between AC and arsenopyrite were investigated. AC-mediated arsenopyrite oxidation was a two-stage process. At stage I, the heterogeneous electron transfer from arsenopyrite facilitated O reduction on AC, enhancing arsenopyrite dissolution and ROS formation. TBA, PBQ and catalase inhibited 86.40 %, 79.39 % and 49.66 % of As(III) oxidation, respectively, indicating indicated that HO˙, (O) and HO were responsible for As(III) oxidation. However, at stage II, the mobility of As was highly restricted, especially increasing AC addition. Besides adsorption, AC retained appreciable As through catalyzing insoluble ferric arsenate formation and growth by promoting Fe(II) and As(III) oxidation and functioning as nuclei. These findings deepen our understanding of the coupling behavior of AC-arsenopyrite and its influence on geochemical cycling of arsenic in mined surroundings, which has important implications for mitigating arsenic pollution.
黄铁矿（FeAsS）的氧化溶解是自然界中砷污染的一个重要来源。生物炭（AC）是一种广泛应用于环境修复的试剂，在生态系统中很常见，并参与了砷和含铁硫化物矿物的各种地球化学过程。然而，AC-黄铁矿结合物对反应性氧化物种（ROS）生成的影响及其对砷转化的贡献很少被探索。在这里，研究了 AC 和黄铁矿之间相互作用过程中 ROS 的形成和砷的氧化还原转化。AC 介导的黄铁矿氧化是一个两阶段过程。在阶段 I 中，黄铁矿的异质电子转移促进了 AC 上的 O 还原，增强了黄铁矿的溶解和 ROS 的生成。TBA、PBQ 和过氧化氢酶分别抑制了 86.40%、79.39%和 49.66%的 As(III)氧化，表明 HO˙、(O) 和 HO 是 As(III)氧化的原因。然而，在阶段 II 中，As 的迁移性受到高度限制，特别是随着 AC 添加量的增加。除了吸附作用外，AC 通过促进 Fe(II)和 As(III)氧化以及充当核来催化不溶性铁砷酸盐的形成和生长，从而保留了相当数量的 As。这些发现加深了我们对 AC-黄铁矿耦合行为及其对矿区周围砷地球化学循环影响的理解，这对减轻砷污染具有重要意义。
