黄铁矿氧化过程中水的作用再认识  

Recognition of the role of water in pyrite oxidation

作　　者：李春花 张倩[2] 张文龙 舒小华[1] 刘杰[1] LI Chun-hua;ZHANG Qian;ZHANG Wen-long;SHU Xiao-hua;LIU Jie(School of Environmental Science and Engineering,Guilin University of Technology,Guilin 541006,China;School of Life and Environmental Sciences,Guilin University of Electronic Technology,Guilin 541004,China)

机构地区：[1]桂林理工大学环境科学与工程学院,广西桂林541006 [2]桂林电子科技大学生命与环境科学学院,广西桂林541004

出　　处：《桂林理工大学学报》2022年第3期695-703,共9页Journal of Guilin University of Technology

基　　金：国家自然科学基金项目(41807392;41967042);广西自然科学基金项目(2018GXNSFBA281097)。

摘　　要：黄铁矿氧化过程中氧气一直被认为是其氧化的主要贡献者,而水的作用往往被忽视。通过对比黄铁矿在有水/无水条件下的氧化情况,探讨了水在黄铁矿氧化过程中的作用机制。结果表明,水在黄铁矿氧化过程中有不可忽略的作用:在无水的条件下,O_(2)直接氧化黄铁矿的反应很难发生;在有水条件下,水被窄禁带半导体黄铁矿产生的空穴氧化生成·OH和H^(+),从而促进黄铁矿氧化和溶解。氧化产物SO_(4)^(2-)中“O”来源于O_(2),而不是水,氧气仍然是氧化的主要贡献者,水在O_(2)氧化黄铁矿的过程中可能起到了预氧化的作用。SEM和XPS分析进一步证实O_(2)在水作用下将黄铁矿氧化为铁氧化物和硫氧化物,导致黄铁矿氧化程度加剧,表面结构出现坍塌。H_2O在黄铁矿氧化过程中可能起到了预氧化作用,丰富了黄铁矿氧化理论,为酸性矿山废水源头防治提供理论依据。Oxygen is usually considered as the main contributor during pyrite oxidation,while the role of water is often overlooked.The mechanism of the role of water in the oxidation of pyrite was investigated by comparing the oxidation of pyrite in the presence/absence of water.The results show that water also plays a non-negligible role in the oxidation of pyrite.Under anhydrous condition,the direct oxidation of pyrite by O_(2) is difficult to occur.In the presence of water,·OH and H+are generated due to the oxidation of water by the holes generated by narrow band gap pyrite,which promotes the oxidation and dissolution of pyrite.It is worth noting that the“O”in the oxidation product SO_(4)^(2-) is derived from O_(2) rather than H2O,so oxygen is the main contributor to the oxidation.Water may play a pre-oxidation role in the oxidation of pyrite by O_(2).SEM and XPS analysis further confirmed that O_(2) oxidized pyrite into iron oxide compounds and sulfur oxygen compounds under the effect of water,leading to oxidation increase and the collapse of surface structure of pyrite.The results reveal the pre-oxidation of H2O in the oxidation of pyrite,enriching the theory of pyrite oxidation and providing a theoretical basis for source control of acid mine drainage.

关 键 词：黄铁矿 水 氧化 酸性矿山废水 

分 类 号：X21[环境科学与工程—环境科学] X54X75