Colloidochemical Processes in the Biotechnology of Heavy Metal Removal from the Soil

The sorption processes of uranium(VI), copper, cobalt, and strontium by the native soil were studied. It was shown that, by their ability to be accumulated by the podsolized soil, these metals are arranged in the following sequence: U(VI) > Cu > Co > Sr. This selectivity sequence is retained during the sorption of metals from mixed solutions containing their equimolar concentrations. The possibility of the leaching of the studied metals from the contaminated soil by Basillus cereusVKM 4368 metal-resistant culture was demonstrated using glucose and sodium acetate as the sources of carbon and energy. In the first case, 90–99% of heavy metals was extracted from the soil as water-soluble citrate complexes. In the second case (during the metabolism of acetate by bacteria), the removal of heavy metals from the soil as hydroxide–carbonate precipitates and complexes was equal to 80–90%. Sedimentation of particles in the soil suspension is accelerated considerably after the treatment by the metal-resistant culture.