科研之友
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摘要
Jarosite is a potential scavenger for the containments such as chromium (Cr) in acid mine drainage (AMD) environments. Microbial decomposition plays an important role in controlling the jarosite stability and Cr behavior. In this study, we investigated the formation of secondary mineral and the fate of Cr during reductive dissolution of Cr-bearing jarosite by Shewanella oneidensis MR-1 (S. oneidensis MR-1) using a batch experiment under anaerobic conditions. Results indicated that S. oneidensis MR-1 can drive the reductive dissolution of jarosite. The incorporation of Cr increased the stability of jarosite, retarding the transformation of jarosite mineral. After 50 days inoculation, the jarosite with no Cr incorporation transformed to vivianite and goethite. However, vivianite was the only secondary mineral for the Cr-bearing jarosite. During the reduction of Cr-bearing jarosite by S. oneidensis MR-1, little Cr released from the Cr-bearing jarosite to the solution initially, and then re-adsorbed to the secondary mineral. The Cr in the fraction of crystalline iron oxide-bound phase changed to amorphous iron oxide-bound phase in biotic treatments, the likelihood of Cr release increased. XPS analysis indicated that the Cr(Ⅵ) in solid surface was obviously reduced Cr(Ⅲ). The toxicity of Cr to surrounding environment decreased. The results of this study are of significant to further understand the geochemistry of Fe, S and Cr in AMD environments.
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