Uranium removal from a radioactive contaminated soil by defined bioleaching bacteria

In order to assess the feasibility of uranium removal technology from radioactive contaminated soil by combined bioleaching bacterial consortia, mixed bacterial culture and pure culture of four strains (Acidithiobacillus ferrooxidans ATCC 23,270, Leptosirillum ferripHilum YSK, Acidithiobacills thiooxidans A01, Acidithiobacillus ferrivorans YL15) were comparatively investigated on uranium removal from a radioactive contaminated soil. The results showed that the mixed bioleaching bacterial consortium exerted good adaptability to the surroundings, showing high biological activity and uranium removal capacity. In the whole cleaning process of uranium contaminated soil, the mixed bioleaching bacterial consortium showed complementary advantages, and the synergistic effect improved the uranium removal efficiency, and the maximum uranium removal of the combined bacteria was achieved to 85.81%. Additionally, the linear fitting analysis showed that the uranium removal was positively related to redox potential and negatively related to pH. Lastly, the soil residue after cleaning was detected by SEM/EDS. The results showed that the liberation degree of uranium-contaminated soil increased significantly after bacterial oxidation, which was conducive to the contact of bacteria and Fe3+ to soil particles, thus improving the uranium removal rate.