Siberian Federal University

The aim of this work was to study the chemical composition and physicochemical properties of humic substances isolated from lowland peat, including their ability to sorb and permanently bind naturally occurring radioactive elements uranium, radium, and thorium. In this work, functional, infrared spectroscopic, and elemental analyses confirmed that the molecules of the humic substances under study contain a large number of reactive groups, which can participate in the processes of sorption of toxic substances. Along with the aromatic character of the studied preparations, a strong branching of the side chains and a high degree of condensation and oxidation of the macromolecules were established. It was also revealed that the exchange capacity indices of the studied humic substances exceed the corresponding characteristics for the known plant-based sorbents by a multiple. Under conditions of static sorption experiment it was established that during a 24-hour contact with solutions of uranyl, radium and thorium nitrates, humic acid preparations sorb up to 74 % of the content of radioactive elements from the liquid phase. Up to 21.8 % of this amount is extracted only by strongly acidic desorbent solutions, a significant amount (up to 45.5 %) was recorded in the structure of humicates. As a rule, a higher proportion of radionuclides irreversibly fixed in sorbents is observed for the sodium form of huminate. The obtained data demonstrate the high potential of the studied humic preparations in the processes of soil remediation