Studying the Influence of the Natural Zeolite Tablets Manufacturing Technology on Sorbtion Kinetic of Long-living 90Sr and 137Cs Radionuclides and Pb2+ and Hg2+ Heavy Metals From Water Solution in Vitro

Aim: To study the influence of the technology on the adsorption activity of natural zeolite tablets (clinoptilolite) in relation to long-lived 90 Sr and 137 Cs radionuclides and Pb 2+ and Hg 2+ heavy metals from an aqueous solution in vitro. Methods: Tablets were prepared by direct pressing and pressing with pre-wet granulation (a moisturizer - 7 % starch paste). Sorption capacity of enterosorbents was investigated by the method of static sorption at pH = 2–8 at a temperature of 37 °С. The concentration of lead in solutions was determined by atomic absorption spectroscopy at the atomic absorption spectrophotometer C-115 PCS. The concentration of mercury was determined by the method of flameless atomization with the help of the mercury device PR-115. The content of radionuclides was determined by the radioactivity of the samples using a radiometer α-β-automaton NRR-610 Tesla. Results: Based on the results of the conducted studies, the adsorption activity of the model specimens of enterosorbents on the basis of natural zeolite in the form of tablets obtained by the technology of direct pressing and pressing with pre-wet granulation, was studied. It has been found that the sorption properties of samples relative to heavy metals and radionuclides depend to a greater extent on the acidity of the solution than on the technology of obtaining tablets. It was found that the process of ion exchange on experimental samples consists of two stages - fast and slow. This fact is explained by the adsorption of ions, primarily within the macro- and mesopor, on the material's surface, and the subsequent reduction of the velocity by diffusion of ions within the microporous space, and the last stage is limiting in the process of adsorption. Comparison of the obtained data on the sorption-selective properties of samples allowed to arrange the investigated ions in order of decreasing their interaction with sorbents Pb 2+ > Hg 2+ > 137 Cs> 90 Sr. Conclusions: It is proved that the technology of obtaining tablets does not significantly affect the activity of the drug in vitro. The results of experimental studies will be used in the further development of the composition and technology of tablets containing natural zeolite (clinoptilolite) as the main active ingredient