BIOSORBENTS BASED ON POLYSACCHARIDES. EVALUATION OF SORPTION CAPACITY IN RELATION TO URANIUM AND THORIUM

Abstract

Study of sorption of heavy natural radionuclide’s uranium and thorium from water by β-gluсancontaining sorbents obtained from biomass of yeast Saccharomyces Cerevisiae and bran of oat Avena sativa was carried out. It is shown that the content of mobile (water-soluble, exchange and acid-soluble) and fixed forms of uranium on investigated β-glucans vary considerably. It is found that the extent of irreversible sorption of uranium does not exceed 58.6%. For the first time shown that β-glucans have high sorption capacity in ratio of thorium. In the conditions of the experiments it was retrieved more than 99% of thorium from the water. The content of fixed form of thorium reaches 94% of the sorbed. Characteristics of surface and capillary-porous structure of samples were defined. The correlation relationships between rates of adsorption and specific surface of preparations were installed. An analysis of the relationship between sorption capacity and various properties of glucans leads to the conclusion that the most important role for the implementation of a strong adsorption of heavy radionuclides belongs to chemisorptions mechanisms, while the contribution of surface physical phenomena is not essential. It is shown that the highest strong adsorption of thorium is characterized by a sample representing the cell walls of yeast Saccharomyces cerevisiae. The findings suggest of β-glucans prospects in practical terms and their use as polyfunctional enterosorbеnts.