Study On Compound Contamination Of Antimony Fixed By Sulfate Reducting Bacteria

With the expansion of mining scale and the continuous application of antimony（Sb）-containing compound products,a large amount of Sb enters the environment.Therefore,the pollution of Sb and its compounds has attracted worldwide attention.Moreover,Sb usually coexists with other heavy metals such as,As,Zn,Cd and Ag in the environment,posing a threat to human beings and the ecological environment.It is a promising remediation method to treat the complex pollution of Sb（Ⅲ）and other heavy metals by sulfate reducing bacteria.This thesis focuses on a series of studies on the composite pollution of Sb,using sulfate reducing bacteria to fix the composite pollution of Sb（Ⅲ）and other heavy metals.The main research results are as follows:Firstly,the feasibility of simultaneous immobilization of Sb（Ⅲ）and Zn（Ⅱ）by sulfate reducing bacteria was explored.After 5 days,the immobilization efficiency of Sb（Ⅲ）and Zn（Ⅱ）were 98.63±1.28%and 98.92±0.37%respectively,and the fixation rate of Zn（Ⅱ）was faster than that of Sb（Ⅲ）.It was found that the addition of Zn（Ⅱ）inhibited the immobilization of Sb（Ⅲ）by microorganisms.It was found through SEM-EDS and XRD that Sb（Ⅲ）and Zn（Ⅱ）existed in the solid state of Sb₂S₃ and Zn S after the reaction.Experiments on the inhibition of metal to Vibrio fischeri luminescence showed that the inhibition ratio of the medium containing Sb（Ⅲ）and Zn（Ⅱ）on Vibrio fischeri gradually decreased by sulfate reducing bacteria.The microbial community results showed that:Proteobacteria and Firmicutes were the main phylum species.Citrobacter played a great role in the fixation of Sb（Ⅲ）and Zn（Ⅱ）.Anaerostignum and Tuzzerella were significantly enriched in the complex pollution system.Dysgonomonas may directly or indirectly participate in the fixation of Sb（Ⅲ）and Zn（Ⅱ）.Secondly,different influencing factors were studied.It was found that Sb（Ⅲ）and Zn（Ⅱ）could be immobilized in a wide p H range（5-9）.The immobilization efficiency of Sb（Ⅲ）and Zn（Ⅱ）increased with the increase of the amount of bacteria solution and the concentration of carbon source.The fixation efficiency of Sb（Ⅲ）and Zn（Ⅱ）also decreased with the increase of the initial Sb（Ⅲ）and Zn（Ⅱ）concentration.Through the study of sulfite reductase activity,it was found that with the increase of time,sulfite reductase activity increased first and then decreased.The single Zn（Ⅱ）reactor had the highest enzyme activity,and the complex system had the lowest enzyme activity.FTIR results showed that the main groups involved in the immobilization of Sb（Ⅲ）and Zn（Ⅱ）were hydroxyl,carboxyl,amido and primary amine.In simulated mine soil Sb（Ⅲ）and Cd（Ⅱ）pollution remediation studies,it was found that after the immobilization of sulfate reducing bacteria,the soil microbial energy metabolism activity increased significantly.At the same time,the stable forms of Sb（Ⅲ）and Cd（Ⅱ）in the soil increased under the action of microorganisms,and the mobility decreased.In summary,this study explored the treatment of combined pollution of Sb（Ⅲ）and heavy metals,and provided new ideas for the restoration of Sb（Ⅲ）.