Arsenopyrite weathering in acid rain: arsenic transfer and environmental implications
Arsenopyrite weathering in acid rain: arsenic transfer and environmental implications
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酸雨中毒砂风化：砷转移和环境影响
DOI：
10.1016/j.jhazmat.2021.126612
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发表时间：
2021
影响因子：
13.6
通讯作者：
Heping Li
中科院分区：
文献类型：
--
作者：
Xiaonan Feng;Qingyou Liu;Shuai Wang;Ling Cen;Heping Li
毒砂在自然界中分布广泛，易风化，易释放砷，污染周围环境。酸雨是一种含有硫氧化物（SOx）和氮氧化物（NOx）的酸性物质，是一种典型的有害物质。毒砂与酸雨的交互作用可能加剧环境恶化。本文采用电化学技术和表面分析方法研究了毒砂在模拟酸雨中的风化行为。循环伏安法、拉曼光谱和X射线光电子能谱分析表明，FeAsS在初始阶段被氧化为Fe 2+、AsO 33-和SO，然后随着H+的积累，Fe 2+转化为Fe 3+，SO转化为SO 32-，最终转化为SO 42-，AsO 33-转化为AsO 43-。极化曲线表明，较高的温度或较高的酸雨酸度增加了毒砂的风化趋势和速率，电化学阻抗谱表明其原因是双电层和钝化膜的电阻变小，电容变大。毒砂风化速率与温度的关系为：lnk= −3824.8/T+ 10.305，通过一个活化焓为29.37 kJ mol− 1和活化熵为− 167.40 J mol− 1 K −1的过渡态。该研究为毒砂风化提供了一种快速、定量的原位电化学方法，加深了对毒砂在酸雨条件下风化的认识。研究结果对酸雨区受采矿活动影响的含砷场地的修复和管理具有重要意义。
Arsenopyrite is widely distributed and weathers readily in the nature, releases As and pollutes the surrounding environment. Acid rain is acidic in nature as contains sulfur oxides (SOx) and nitrogen oxides (NOx), and is a typical hazardous material to human. When arsenopyrite encounters acid rain, their interaction effect may aggregate environmental degradation. In this work, the weathering behavior of arsenopyrite in simulated acid rain was studied using the electrochemical techniques and surface analysis. Cyclic voltammetry and Raman and XPS confirmed that FeAsS was oxidized to Fe2+, AsO33-and S0at the initial phase, then, Fe2+was converted to Fe3+, S0transformed to SO32-and ultimately to SO42-, and AsO33-to AsO43-with the accumulation of H+. Polarization curve revealed higher temperature or higher acidity of acid rain increased the weathering trend and rate of arsenopyrite, and electrochemical impedance spectroscopic measurements showed the causes behind this to be smaller resistance and greater capacitance at the double layer and passivation film. Arsenopyrite weathering rate and temperature has a relationship: lnk= −3824.8/T+ 10.305, via a transition state with activation enthalpy 29.37 kJ mol−1and activation entropy − 167.40 J mol−1K−1. This study provides a rapid and quantitative in-situ electrochemical method for arsenopyrite weathering and an improved understanding of arsenopyrite weathering in acid rain condition. The results have powerful implications for the remediation and management of As-bearing sites affected by mining activities in acid rain area.