Kernosenko L. Colloid-chemical processes of heavy metal biotransformation in soil

The thesis is devoted to the study of the colloid-chemical properties of the natural soil containing heavy metals: uranyl, copper, strontium, cobalt, and introduced metal-resistant culture, the possibilities to extract heavy metals by their bacterial transformation from bonded form into water-soluble form of non-toxic citrate complexes. It is shown that metal leaching from soil during the microbial metabolism of the organic substrates takes place much effectively in the form of citrate complexes as compared with hydroxide-carbonate colloid precipitates (copper, cobalt, strontium) or water-soluble carbonate complexes (uranyl). The efficiency of the metal leaching decreases in the following succession: U(VI) > Cu > Co > Sr which coincides with the selectivity row of their sorption in the natural soil established by us. The possibility of the biological destruction of water-soluble organic Ca, Mg, Zn, Sr, Ni, Cu, Co, and uranyl complexes accompanied by the transfer of heavy metals in the colloid form represented by practically insoluble carbonates and hydroxides has been demonstrated. Non-toxicity (ecological safety) of the organocomplexes of heavy metals and the products of their biotransformation has been established. The effective colloid-chemical biotechnology for the natural soil cleaning from heavy metals and radionuclides.