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Results of the experimental investigation of the filtration of natural waters and gel-forming solutions through sand under the conditions simulating the aeration zone in the area of ground storage facilities of the Siberian Chemical Combine (SCC). Model porous media from natural sand ground samples of the aeration zone in the area of SCC surface storage facilities in the first aquifer from the surface were used in the experiments. Sorption and plugging properties of anti-filtration gel barriers (screens) formed by various thermotropic gel-forming systems were evaluated. Low-viscosity gel-forming compositions were pumped into the model porous medium. They were transformed into gels directly in the porous medium according to the mechanism of hydroxopolycondensation of aluminium ions or phase transitions of the polymers with lower and upper critical dissolution temperatures with the formation of anti-filtration barriers. The anti-migration properties of anti-filtration gel screens on the migration path of polluted waters in the first aquifer from the surface were investigated. Solutions of cesium and strontium salts were used as simulators of radioactive contaminants. To enhance the anti-migration properties of the gel barriers, we used preliminary impregnation of the rock with a sodium tetraborate solution, as well as the introduction of potassium alum into the gel-forming compositions. It was established that the anti-filtration gel screen based on polyvinyl alcohol (PVA) has also anti-migration properties. On the basis of the results of experimental studies, the PVA-based composition is recommended for making anti-filtration and anti-migration barriers on the migration path of contaminated water in the area of ground storage facilities of the SCC. It is reasonable to pump a portion of the solution of sodium tetraborate before and after injection of the composition.

Some examples of the technological developments implemented at the Experimental Chemical Plant of the Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, in collaboration with the Rosatom State Corporation, for application in various areas are considered. The technology for the synthesis of basic polyfluoroaromatic compounds (hexafluorobenzene, chloropentafluorobenzene and isomeric dichlorotetrafluorobenzenes) was developed. The key stage of the process is the substitution of chlorine atoms in hexachlorobenzene under the action of anhydrous potassium fluoride in an autoclave at 450-550 °C. The production of grand lots of a number of high-purity crown ethers was developed and optimized, which allowed their use in actual industrial processes for selective extraction of some metals. A commercially available biologically active preparation accelerating the growth, development and general stability of plants to diseases was created as a result of fundamental studies of triterpene compounds extracted from Siberian larch.

Advances in the scientific directions launched by A. A. Kovalsky, an outstanding expert in Physics and Physical Chemistry, participant of the works on the Atomic Project, the first Director of the Institute of Chemical Kinetics and Combustion SB RAS are considered. The works aimed at the development and investigation of the properties of new types of energy materials and inhibitors of combustion proceed on the basis of the notions on the mechanisms of ignition and combustion formulated by A. A. Kovalsky. Aerosol studies that were initiated within the framework of the Atomic Project for protection from irradiation formed the basis for the development of aerosol-based method to protect forests and agricultural plants from pests. Works initiated by Kovalsky gave rise to new aerosol-related directions: methods and instruments for measuring the characteristics of aerosol particles are under development, methods are elaborated for the generation of aerosol with necessary particle sizes and concentrations for various applications including nanoaerosol pharmaceutical forms, chemical properties and biological effects of nanosized substances are under investigation. Perspectives for further progress in these areas are outlined.

The microsphere composites were prepared by covering microsphere glass-crystalline supports with as-synthesized crystalline zirconium molybdate (Mo/Zr = 1.7) and pre-synthesized microporous sodium zirconium silicates of hilairite and gaidonnayite structural types. Narrow fractions of coal fly ash cenospheres with (SiO₂/Al₂O₃)_wt of 2.7 and 3.0 were used as precursors of the supports. The composites were studied by means of SEM, EDX and PXRD. The efficiency for Cs⁺ and Sr²⁺ removal from simulated wastewater was evaluated on the basis of parameters, such as the distribution coefficient K _d (for low Cs⁺/Sr²⁺ concentrations) and the maximum sorption capacity a _m (for high Cs⁺/Sr²⁺ concentrations) determined from the Langmuir sorption isotherms. It was established that the composites trap Cs⁺ and Sr²⁺ with K _d of up to 10⁴ mL/g. The influence of zirconium molybdate and sodium zirconium silicate composition and structure on their sorption abilities was demonstrated. The proposed resource-saving approach to the preparation of composite sorbents along with their high sorption parameters favours their application for decontamination of ¹³⁷Cs and ⁹⁰Sr bearing wastewater including aquatic environment and technological solutions.

The possibility of hydrothermal synthesis of Cs and Sr bearing framework aluminosilicates in the CsNO₃-NaOH-H₂O-(SiO₂-Al₂O₃)_glass and Sr(NO₃)₂-NaOH-H₂O-(SiO₂-Al₂O₃)_glass systems using coal fly ash cenospheres was studied as a low-temperature method to include the water-soluble forms of radionuclides ¹³⁷Cs и ⁹⁰Sr in a mineral-like form. The syntheses were carried out at temperatures in the range of 80-200 °С and autogenous pressure. Narrow fractions of cenospheres with the glass phase content of 90-95 mass % were used as aluminosilicate glass, and compounds of stable isotopes of Cs and Sr were used as imitators of radionuclides ¹³⁷Cs и ⁹⁰Sr. Based on the data obtained in the studies of solid products and post-synthetic solutions by means of X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray microanalysis (SEM-EDX) and atomic absorption spectroscopy (AAS), it was established that the Cs bearing analcime-pollucite solid solutions (Na _n Cs_{1- n} )AlSi₂O₆∙ n H₂O are crystallized in the Cs-containing system at 120-150 °C with 98 % Cs⁺ removal from solution to the solid product. The Sr bearing phases of tobermorite and plagioclase structural types are formed in the Sr(NO₃)₂-NaOH-H₂O-(SiO₂-Al₂O₃)_glass system. In this case, the effectiveness of Sr²⁺ extraction from solution is not less than 99.99 %.

An overview of the research of the Boreskov Institute of Catalysis SB RAS in the field of the use of catalytic processes to neutralise the mixed organic waste containing radionuclides is given. An ecologically friendly technology was proposed for ecologically safe neutralization of mixed organic wastes containing radionuclides U, Pu and fission products. This technology is based on flameless lot-temperature oxidation of the organic component of the waste in a fluidised bed of catalyst granules and the transition of radionuclides into the compact solid phase for subsequent processing or disposal. The technological scheme includes a catalytic reactor for waste oxidation and a flue gas purification system. The process was investigated on experimental installations during the catalytic combustion of model mixtures and real radioactive waste containing uranium formed in the production of fuel rods. Various regimes of catalytic combustion of mixed waste and gas purification processes were elaborated. Based on the research conducted, a technological scheme and a technical project of the demonstration plant for the treatment of mixed organic waste were developed. The plant was constructed and assembled at the JSC Novosibirsk Chemical Concentrates Plant. For neutralization of the wastes of extractants containing radionuclides, oxidation in catalytically active melts was investigated. The effect of melt composition, oxygen concentration, load and temperature on process efficiency was studied. Optimal process parameters were determined. On the basis of these results, an experimental installation for processing real liquid organic wastes (worked out extractants) containing U and Pu radionuclides was designed and built at the Siberian Chemical Combine. Installation tests demonstrated the high efficiency of the oxidation of organic components of the wastes and complete absorption of phosphorus and radionuclides U, Pu by the melt.

The main directions of the depleted uranium compounds utilization, modern trends in the use of uranium oxides and complex compounds based on them in catalytic processes, and methods for producing uranium oxides are considered in the review. It is shown that oxygenated uranium compounds are promising in all areas of catalysis, including environmental protection processes, organic synthesis, photocatalysis, electrocatalysis, processes for the production of hydrogen and valuable chemical compounds. The achievements of the Boreskov Institute of Catalysis SB RAS in the development of methods for the production of uranium oxides with different U/O ratios and uranium-containing catalysts for environmental protection and hydrogen production within the framework of the international program “Development of technology for the production of new effective catalysts based on raw materials from depleted uranium oxides” are described in detail. The review includes foreign and domestic publications from 1955 to 2021.

The effect of the salting-out agent, aluminium nitrate (Al(NO₃)₃), on the extraction properties of hexavalent uranyl and plutonyl nitrates (UO₂(NO₃)₂ and PuO₂(NO₃)₂) is studied. It is shown that in 4-8 М HNO₃ solutions (aqueous phase) with an increase in Al(NO₃)₃ concentration from 0.1 to 1 M, uranium distribution coefficient increases sharply during extraction in 30 % solution of tributyl phosphate (TBP) in a hydrocarbon solvent (organic phase). In the presence of aluminium nitrate, the distribution coefficient of Pu⁶⁺ increases most significantly in comparison with other valence forms of Pu. The efficiency of salting-out action increases with an increase in TBP concentration in the organic phase: in the presence of 0.1-2.0 М Al(NO₃)₃, the distribution coefficient of Pu⁶⁺ in a 30 % solution of TBP increases three times faster than in its 4.5 % solution. The efficiency of reductive stripping of hexavalent plutonium (Pu⁶⁺) by tetravalent uranium (U⁴⁺) increases in the presence of aluminium nitrate. In the presence of 1 M Al(NO₃)₃, the coefficient of PuO₂²⁺ distribution does not exceed 1.0 even at low concentrations of U(NO₃)₄ (50 g/L) and HNO₃ (0.5 M). The concentration of HNO₃ in the aqueous phase strongly affects the change in Pu⁶⁺ distribution coefficient. However, with an increase in the concentration of U(NO₃)₄ in the stripping solution, the rate of a decrease in the coefficient of Pu⁶⁺ distribution drops down. With an increase in U(NO₃)₄ concentration from 50 to 150 g/L, this parameter decreases by a factor of 2.6, and in more concentrated U(NO₃)₄ solutions (150-250 g/L) it decreases by a factor of 1.1.

Use of the basin approach and other modern research methods (information-logical analysis, and geomodeling) helped to reveal the interaction and special features of the mutual location of geosystems of altitudinal belts and river catchments which form the characteristic features in the differentiation of vegetation and soil cover in mountain conditions. It is shown that the landscape pattern and morphometric characteristics of river basins indicate different processes of destruction of the mountain massif in the western and eastern parts of the Basegi Ridge. It was found that the asymmetry in the slopes of the ridge and the associated hydrothermal conditions lead to a differentiation in the structural organization of the basins. This study determined the degree of dependence of the plant community and the soil type on the slope steepness and exposure, the absolute elevation and structural elements of the catchments of small rivers. According to an enhancement in the degree of influence on the growth conditions of plant communities, the topographic features under study form a series: slope exposure < elements of river ba sins < slope steepness < height above the sea level in meters. Specific conditions of vegetation and soils corresponding to the elements of the basin are determined. It is concluded that tundra and meadow vegetation is more informative. Based on the generalized spatial analysis, the cartographic model was developed for the soil cover of the Basegi Ridge. The elements of the catchments are characterized by different soil cover. A maximal diversity of plant communities and soil cover variegation on the slope surfaces of river basins is more clearly pronounced. Soil cover variegation implies a combination of zonal soils (Brown forest soils, Cambisols) of the mountain taiga and azonal soils (Gleezems (Gleysols) and peat soils (Histosols)). Hence, with the processes of basin formation predominating, the slopes show some “deformation” of the existing structure of altitudinal-vegetation belts. In watershed spaces, above the energy zones (catchment funnels), the influence of basin formation is weakening and the altitudinal zonation-associated differentiation is enhanced.

Presented are the results from investigating the atmospheric self-purification capacity over the cities of Irkutsk, Beijing and Ulaanbaatar for the summer and winter seasons of 2017-2018. The meteorological potential of the atmosphere (MPA) was used as the criterion for assessing the atmospheric self-purification. It is shown that in the summer season of 2017 the favorable meteorological conditions for the dispersion of air pollutants were dominant over the territory of Irkutsk and Ulaanbaatar. In the summer, MPA was 0,99 and 0,78 in Irkutsk and in Ulaanbaatar, respectively. MPA varied from 2,14 to 4,66 in Beijing in the summer. For the winter months in the three cities, MPA > 1, which indicates an accumulation of pollutants in the atmosphere for that season. In Ulaanbaatar there were unfavorable conditions for self-purification: the maximum MPA index (9.5) was observed in December. The largest contribution to impairment of the atmospheric diffusing capacity over Ulaanbaatar in the wintertime was made by wind velocities of 0-1 m/s. It was found that the maximum accumulation of pollutants in the atmosphere over Beijing occurs in the winter. MPA varied from 15,0 in February to 19,03 in December, averaging 16.68. Fogs made the largest contribution to the unfavorable meteorological conditions of Beijing in December-February. The characteristic properties of the atmospheric circulation, wind regime, fog and atmospheric precipitation were responsible for MPA of Irkutsk, Ulaanbaatar and Beijing for the period under consideration.