Oxidation/reduction Bacteria And Its Combined Immobilization With Montmorillonite On Heavy Metal

Heavy metal pollution is one of the serious problems in the environmental pollution,and has aroused the concern of the researchers.The current research on microbial or montmorillonite to remove heavy metals is common,but the research is limited to to a single bacterium or montmorillonite.In addition,the heavy metals abosorbed by minerals could be dissolved out again,thus making the removal incompletely.Therefore,in this paper,the combination of montmorillonite and Thiobacillus denitrificans was used in to remove heavy metals according to the rapid adsorption of montmorillonite on Sr2+ and the finally mineralization and immobilization capacity by Thiobacillus denitrificans.In this paper,three oxidation bacteria(Thiobacillus denitrificans)and one reducing bacteria(Sulfate-reducing bacteria)were isolated from the soil and sludge by selective medium,respectively.The growth characteristics were studied and SO42-and S2-were produced during their growth.The Thiobacillus denitrificans were used for Sr2+ mineralization and the removal rate was up to 81.4%,SEM/EDS,XRD,FTIR analysis found that the mineralization product was celestite.The Sulfate-reducing bacteria was used for Cd2+ and Pb2+ mineralization and removal rate was up to 92.3%and 93.4%,and the mineralization product was Cds/PbS.The analysis of combined retention/fixation effect on Sr2+ by montmorillonite-Thiobacillus denitrificans mineralization system was carried out,and the result showed that the removal rate of Sr2+ was up to 96.2%.Through the analysis of dissolution/fixation action of the Sr-M2-Thiobacillus denitrificans system(The 20g/L montmorillonite and Thiobacillus denitrificans were added to the 1000mg/L Sr solution).the result showed that the dissolution rate and the fixation rate was 79.6%and 84.2%,respectively,the mineralization effect of the system was good,and the dissolution rate and cure rate of Sr2+ in the system increase with time.This paper built the combination system of montmorillonite-Thiobacillus denitrificans for Sr2+ removal.The removal efficiency was good.This study is expected to provide reference basis for treatment for soil or water contaminated by a high concentration of heavy metal,and simultaneously provided a reference for rapid in situ treatment of sudden pollution of heavy metal or nuclide.