摘要
Acid mine drainage(AMD)has become a widespread environmental issue and its toxicity can cause permanent damage to the ecosystem.However,there are few studies focusing on the formation of AMD under moderately thermophilic conditions,hence we employed X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS)and 16S rRNA sequencing to study the dissolution of pyrite and bornite by a moderate thermophilic consortium,and explored the role of free and attached microorganisms in the formation of AMD.The consortium mainly comprised Acidithiobacillus caldus,Leptospirillum ferriphilum and Sulfobacillus thermosulfidooxidans.The results indicated that total iron in pyrite solution system reached 33.45 g/L on the 12th day,and the copper dissolution rate of bornite dissolution reached 91.8%on the 24th day.SEM results indicated that the surfaces of pyrite and bornite were significantly corroded by microorganisms.XRD and XPS results showed that ore residues contained jarosite,and the dissolving residue of bornite contained elemental sulfur.The dominant bacterial genus in pyrite dissolution was A.caldus,and L.ferriphilum in bornite dissolution.To sum up,microbes significantly accelerated the mineral dissolution process and promoted the formation of AMD.
酸性矿山废水(AMD)的毒性会对生态系统造成永久伤害,但关于中度嗜热条件下AMD形成的研究很少。本文通过Acidithiobacillus caldus、Leptospirillum ferriphilum和Sulfobacillus thermosulfidooxidans三种中度嗜热混合菌对黄铁矿和斑铜矿进行生物溶解,采用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)和16S rRNA高通量测序来研究其溶解行为,并探讨了游离和吸附微生物在AMD形成中的作用。结果表明,在第12天黄铁矿溶解体系中总铁达到33.45 g/L,第24天斑铜矿溶解体系中铜的溶解率达到91.8%。SEM结果说明,黄铁矿和斑铜矿的表面受到微生物的明显腐蚀。XRD和XPS结果表明,两种矿的溶解矿渣中含有黄钾铁矾,斑铜石溶解矿渣中还含有元素硫。黄铁矿溶解体系中的优势菌是A.caldus,斑铜矿溶解体系中的是L.ferriphilum。综上所述,微生物显著加速了矿物溶解过程,促进了AMD的形成。
基金
Projects(51934009,52074353)supported by the National Natural Science Foundation of China
Project(2019YFC1803600)supported by the National Key Research and Development Program of China
Project(2021JJ30855)supported by the Natural Science Foundation of Hunan Province,China。
