嗜酸铁/硫氧化菌浸出煤矸石中硫的形态变化

Variation of sulfur speciation of coal gangue leaching by acidophilic ferrous/sulfur oxidizing microbes

利用嗜酸铁/硫氧化微生物Acidithiobacillus thiooxidans SOB-1和Acidithiobacillus ferrooxidans SOB-2浸出煤矸石,利用XRD和硫的K边X-ray Absorption Near Edge Spectroscopy(XANES)分析煤矸石浸出前后物相组成和硫的形态变化。XRD结果表明:经浸出处理后矸石中黄铁矿消失,其他矿物组成变化不明显。XANES结果表明,原始矸石中硫形态主要是黄铁矿硫,氧化型谷胱甘肽硫,硫代硫酸盐硫,单质硫和少量噻吩硫。与空白对照相比,SOB-1对矸石浸出效果较差,样品中各种形态硫的含量变化不明显;而SOB-2及SOB-1和SOB-2的混合菌对矸石中总硫和黄铁矿均有较好的脱除效果,其脱除率最高可达51.08%和71.5%。矸石样品中的黄铁矿硫经氧化转变成硫代硫酸盐硫和硫酸盐硫,SOB-2和混合菌明显促进了硫的形态变化,并且两株菌及其混合菌可能对噻吩硫也有一定脱除效果。

Acidophilic iron and sulfur oxidizing microorganisms Acidithiobacillus thiooxidans SOB-1 and Acidithiobacillus ferrooxidans SOB-2 were used to bioleach the coal gangue,and its sulfur speciation variations after leaching were analyzed with XRD and sulfur K-edge X-ray absorption near edge spectroscopy （XANES）.XRD results showed that the pyrite in coal gangue disappeared after leaching treatment,however,the other mineral components always remained unchanged.XANES showed that the sulfur speciation in original coal gangue were mainly sulfur of pyrite,oxidized glutathione,thiosulfate,sulfate and a small amount of thiophene （DBT）.Compared with sterile control,the SOB-1 had poor effect on gangue leaching and the sulfur content variation in which was not obvious.Nevertheless,both SOB-2 and the mixed culture of SOB-1 and SOB-2 had an excellent ability on removing total sulfur and sulfur of pyrite in coal gangue and the highest removing rate of which were up to 51.08% and 71.5%,respectively.The pyrite in coal gangue could be oxidized to thiosulfate and finally to sulfate,furthermore,the SOB-2 and mixed culture clearly improved the transformation of sulfur speciation.On the other hand,it seems that both two strains and their mixtures had ability to remove the sulfur of DBT.