Electrochemical study of arsenopyrite weathering
Electrochemical study of arsenopyrite weathering
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DOI：
10.1039/b210631k
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发表时间：
2003-01
影响因子：
3.3
通讯作者：
C. Almeida;B. Giannetti
中科院分区：
文献类型：
--
作者：
C. Almeida;B. Giannetti
循环伏安图和电容测量用于表征相对温和的环境条件（pH 4.5 和 T = 25 °C）下的矿物响应。实验涉及检查非生物氧化的毒砂的氧化速率和表面形态。对矿物的半导体特性进行了研究，试图获得 FeAsS 在酸性溶液中在接近矿物开路电位的电位下溶解行为的更多信息。还提出了在开路条件下毒砂阳极溶解的机制途径。在高过电势下，阳极反应主要产生硫酸根和砷酸根离子，并且可以被描述为空穴限制。讨论了在比开路电位更负的电位下类雌黄化合物的还原。
Cyclic voltammograms and capacitance measurements are presented to characterize the mineral response at relatively moderate environmental conditions, pH 4.5 and T = 25 °C. The experiments involve examining the rates of oxidation and the surface morphology of arsenopyrite, which is oxidized abiotically. The semiconducting properties of the mineral have been investigated in attempt to gain additional information of FeAsS dissolution behavior in acidic solutions at potentials close to the open circuit potential of the mineral. A mechanistic pathway for the anodic dissolution of arsenopyrite in open circuit conditions is also suggested. At high overpotentials, anodic reactions produce mainly sulfate and arsenate ions and may be described as hole limited. The reduction of orpiment-like compounds at potentials more negative than the open circuit potential is discussed.