The ability of natural and modified montmorillonite clays from Belgorod oblast to sorb Cs, Sr, U, and Pu radionuclides was studied. The clays were modified by treatment with metal (Li + , Na + , K + , Mg 2+ , Ca 2+ , Fe 2+ , Zn 2+ ) chloride solutions or aqueous HCl. The natural and modified clays studied show high performance in sorption treatment of solutions to remove Cs radionuclides. The natural clay and the Na and Mg forms of clays show the best sorption characteristics with respect to Cs. The distribution coefficient K d of 137 Cs in sorption on the above samples from a 0.1 M NaNO 3 solution is (1.1-1.4) × 10 4 cm 3 g -1 , which is 4-5 times higher compared to natural clinoptilolite. The Sr, U, and Pu radionuclides are sorbed on the examined clay samples to a considerably lesser extent. The K d values in sorption of these radionuclides from tap water are lower by 2-3 orders of magnitude than in sorption of Cs. Addition of clay materials in the course of cementation of liquid radioactive wastes, including NPP bottom residues, allows the rate of radiocesium leaching from the hardened cement compounds to be decreased by a factor of 5-16. The most efficient sorption additive in cementation of NPP bottom residues is natural montmorillonite clay.

A comprehensive study of the material composition of clay raw materials of the al-Najaf field (Iraq), which belongs to the sedimentary deposits of the Dammam formation, is conducted. The features of the chemical and phase composition of the rock are determined using x-ray phase, energy dispersive, microrentgenospectral, electron microscopic and thermogravimetric methods of analysis. The presence of titanium as an impurity element is detected in the studied clay along with the typical element composition of aluminosilicates using energy-dispersion-spectral analysis. At the same time, a high total content of oxides of alkaline and alkaline earth metals (Cao, Na2O, K2O) is recorded, amounting to more than 5.0 wt. %. It is found that the sample under study has a polymineral composition, the main rock-forming minerals are kaolinite, illite and montmorillonite. The total percentage of the clay component is more than 82 wt.%. Content of clay particles belonging to high-and medium-dispersed fractions (size 10 microns or less) it is more than 60% by weight. The average size of the particles composing the studied clay is about 32.0 microns. Based on the data on the chemical, mineralogical and granulometric composition of the sample, a conclusion is made about the potential suitability of the studied clay as a sorption-active material, as well as in the production of Portland cement and coarse ceramics.

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This paper presents the results of a comparative assessment of the effectiveness of sorption purification of aquatic medium and fertile soils using native forms of bentonite clays of deposits in the Belgorod region (Russia) from heavy metal ions (Cu2+, Fe3+, Cr3+, Pb2+) and radionuclides (137Cs, 85Sr, 233U и 239Pu). It was revealed that during the sorption of heavy metal ions (Cu2+, Fe3+ и Cr3+) from model water systems, the most absorbing activity is shown by the natural clays of the Polyana and Nelidovka deposits, which have almost the same ability to absorb heavy metal ions. The purification efficiency of the model aqueous solutions from these cations taken at an initial concentration of 0.1 mmol/l reaches 95%. It was established that the natural clay of the Polyana deposit is also an effective sorbent for the purification of solutions from cesium radionuclides. In terms of sorption ability, the studied sample is 5 times superior to natural clinoptilolite, which is most often used to purify solutions from radiocesium.. It was revealed that with an increase in the amount of added sorbents, the detoxification effect is increased, that is, the content of heavy metals in the green mass decreases.

The species Sanguisorba officinalis L. is widespread in the Republic of North Ossetia-Alania and is promising for the study and practical use of the pharmacological and food industry. The aim of the work is to analyze the dynamics of biologically active substances in the phytomass S. officinalis depending on the altitude gradient under conditions of RNO-Alania. Studies were carried out in 2012-2016. Samples of vegetable raw materials were taken at 5 stationary points located in various high-altitude belts: 1079, 1480, 1760, 1810 and 2300 m above the sea level. Studies were conducted using standard methods. The air-dry yield of S. officinalis above-ground phytomass in an averaged between 0.669 to 1.05 kg/m 2 over the years of research. The content of the studied biologically active substances in the above-ground phytomass of S. officinalis was found to change with increasing growth height. At a height of 1079 m, a high content of nitrogen-free extractive substances, hydroxycoric acids (in terms of chlorogenic), leukoantocyans, catechins, tanning substances was found in tissues. At a height of 1480 m, the accumulation of crude protein and routine was observed. At an altitude of 1810 m, fiber, ash elements, ascorbic acid, saponins (in terms of ursolic acid), and carotenes accumulate in grass. At a height of 2300 m, plant tissues show maximum levels of crude fat and flavonoids. The obtained data make it possible to estimate antioxidant and P-vitamin properties of S. officinalis and to recommend collection of vegetable raw materials of S. officinalis at different height to obtain certain biologically active substances. Effective and low-toxic natural polyphenolic antioxidants of S. officinalis can be used in the food, cosmetic and pharmaceutical industries.