Titration curves of H-forms of the fibrous chelating sorbent with iminodiacetic groups based on industrial polyacrylonitrile fiber Nitron with potassium hydroxide in 1M KCl solution in the presence of Ni²⁺, Co²⁺, Cu²⁺ and Ca²⁺ chlorides were obtained. The method used made it possible to simultaneously measure the pH of the solution and the concentration of the divalent cation at each point of the titration curve. From these data, the dependences of their sorption values on the pH of the equilibrium solution were calculated. The curves of direct and back titration practically coincided in all cases. As the pH changed during titration, precipitation was observed at pH values of precipitation of the corresponding hydroxides. In this case, the increase in pH was suspended or greatly slowed down by adding alkali to the titration cell. The formation of a precipitate occurred mainly in a solution for Co²⁺ and Ni²⁺ (pH 8), when the ion exchanger was saturated with a metal ion. In the case of Cu²⁺ (precipitate formation pH 4), Cu²⁺ sorption occurs at both lower and higher pH due to ionization of carboxyl groups and partial dissolution of the precipitate. In all cases, the maximum sorption of Ni²⁺, Co²⁺, Cu²⁺, Ca²⁺ corresponded to the formation of sorption complexes of the R–N(CH₂COO^-)₂Me²⁺ type.

The article is devoted to the study of the nature and number of acid-base centers on the surface of chromium(III) oxide obtained by precipitation from an aqueous nitrate solution. The curve of the distribution of the number of acidbase centers of the samples is plotted depending on the indicator of the ionization constant of indicators. It was determined that the main Lewis centers make the main contribution to the acidity of the samples; there are also Bronsted centers of different acidity. A comparative analysis of the structural features of the surface of oxides of chromium, zinc and binary systems Cr (III)–Zn (II) was carried out according to the results of X-ray phase analysis of oxides and thermolysis of the corresponding hydroxides. Based on this, the possibility of obtaining nanosized catalysts based on oxide-hydroxide systems of chromium with a number of 3d-metals obtained in the process of polynuclear hydroxocomplexation is predicted.

Sorbtion of dipeptides leucylisoleucine, threonylthreonine and their monomeric amino acids leucine and threonine by anionite AV-17 and cationite KU-2-8 in a wide range of equilibrium concentrations has been studied. It was shown that the presence of hydrophilic OH-groups in the threonine molecule promotes superequivalent sorbtion of threonine on the cation exchanger. The presence of an OH-groups in the side chein of the dipeptide practically does not affect the sorbtion an KU-2-8. Sorbtion of dipeptides on AV-17-8 is higher in comparison with their monomeric amino acids.

The distribution of six acid-type penicillins (penicillin G, penicillin V, oxacillin, cloxacillin, nafcillin, dicloxacillin) in the extraction systems of chloroform–aqueous solutions of ammonium sulfate was studied. The reported distribution coefficients values of penicillins demonstrated the effectiveness of using ammonium sulfate as a salting-out agent. Based on the data obtained, a procedure for milk sample preparation was developed for the quantification of the residual content of six acid-type penicillins.

Condensed indole derivatives of the 1,2,4-triazino[5,6-b]indole group show high biological activity and are of interest for the development of pharmaceuticals that have antihypoxic and antisurditant effects. By S-aminoalkylation reactions on a thione group, S-aminoalkyl derivatives of 1,2,4-triazino[5,6-b]indole-3-thione that were subject to hydrobromination in order to obtain the form of hydrobromides were synthesized, isolated and characterized.

A system has been developed to identify 11 genetic markers associated with the risk of obesity: rs10852521, rs11075990, rs1121980, rs1421085, rs1477196, rs17817449, rs3751812, rs7206790, rs8047395, rs9940128 (FTO gene) and rs1137101 (LEPR gene) by minisequencing (SNaPshot analysis). The conditions for carrying out the amplification and minisequencing reactions, as well as the compositions of the reaction mixtures, were optimized so that the analysis was carried out for all 11 markers simultaneously. The resulting system was tested and showed a high degree of reproducibility and sensitivity required for the detection of these polymorphisms.

Aluminum orthophosphate of the composition AlPO₄·2H₂O with a monoclinic structure identical to the structure of the natural mineral metavariscite was obtained by condensation method during hydrothermal treatment of alumophosphate solutions with a concentration (g/l) of Al₂O₃ 90 – 115, P₂O₅ 340 – 440 in the temperature range 95–99 °C. For the first time, the role of aging of the alumophosphate system in shortening of the induction period, simultaneous nucleation of primary particles in the entire volume of the solution and the formation of a pasty product with a predominant particle size of 1–10 μm, in contrast to 30–50 μm, characteristic of a fine-crystalline product obtained without aging of the solution, is established. It is shown that pasty AlPO₄·2H₂O, in comparison with fine-crystalline, is hardly soluble in HCl even under prolonged heating. The influence of P₂O₅ content in the alumophosphate solution, the conditions of its aging and the duration of hydrothermal treatment on the particle size distribution for synthesized aluminum orthophosphates have been established. Anhydrous alumophosphate obtained by dehydration of pasty AlPO₄·2H₂O in the temperature range of 150–200 °C with subsequent heat treatment at 900 °C is readily soluble in acids, and the predominant particle size is 5–13 μm.

In the article the results of studying the sites of industrial enterprises, which have stopped their activities fully or partially in Minsk, are discussed. It is shown that in most cases the re-development of industrial sites with a change of their functional purpose is carried out after 10 years or more. Based on the results of preliminary investigation of a number of the former industrial sites, it was established that such sites continue to be sources of pollutants after the completion of enterprises activity. The enrichment of technogenic substrates carried out from industrial sites by surface runoff (sediments near storm collectors and in topographic lows) with heavy metals is shown. The average content of cadmium in sediments is 2,6 (maximum – 3,9), lead – 3,1 (14), copper – 2,5 (2,2), zinc – 1,7 (2,8), nickel – 3,3 (8,0), chromium – 3,4 (6,6) times higher than in soils. The established standards for lead were exceeded in 63 % of cases, for cadmium – in 77 %, for zinc and copper – in 100 % of cases. The maximum permissible concentration was exceeded 5 times for at least one indicator in almost half of the samples (44 %). The dependence of heavy metals accumulation on the specialization of previously carried out industrial activities is shown. The need for improvement of scientific and methodological approaches to studying of contaminated and potentially contaminated post-industrial areas in connection with their planned re-profiling for urban planning purposes is discussed.

The paper presents the results of 106Ru radionuclide behavior regularities study in aqueous solutions in a wide pH range by ultrafiltration, ion exchange and centrifugation methods. The regions of ¹⁰⁶Ru various species existence in solution have been established: cationic ¹⁰⁶Ru species at pH < 3.5; the transition region of non-ionic species formation in the range of pH 3.5–4.2 and the region of non-ionic species predominant formation at pH > 4.2. A characteristic feature of the studied solutions is the formation of non-ionic particles by microconcentrations of ¹⁰⁶Ru via pseudocolloids at lower pH values as compared to ruthenium solutions with a concentration of 10^-6–10^-4 mol/dm³. The established regularities of the behavior of ruthenium radionuclides can be utilized to increase the efficiency of ion exchange and membrane separation methods at nuclear and radiation facilities for technological solutions and liquid radioactive waste treatment.

Due to the fact that polyhalite ores are poorly soluble in water, it was of interest to study the method of their processing using acids. The influence of polyhalite size, the hydrochloric acid concentration and consumption, the ratio of L: S, the temperature and time of mixing the pulp on the useful components extraction into the solution have been studied. The optimal conditions for the decomposition of polyhalite with hydrochloric acid have been determined. The degree of useful components extraction into the solution depends on the concentration of hydrochloric acid or on the L:S ratio of the pulp, but in all cases the decomposition of polyhalite occurs without secondary crystal formation, as evidenced by the same degree of potassium and magnesium ions extraction. The degree of potassium and magnesium ions extraction from polyhalite into solution increases with decomposition process temperature, an increase in the consumption of acid and the duration of the reagents interaction, and decreases with increasing acid concentration. The CaSO₄ content in the solution increases sharply with an increase in the HCl concentration and is practically independent of the process temperature. Hydrochloric acid extract can be used for phosphate raw decomposition in order to obtain complex fertilizers.

The processes of obtaining compositions based on organosilicon resin for a heat-resistant coating of accelerated drying, as well as its hydrophobization by creating an isotropic nano-microstructure on the surface, are studied. It is shown that the chemical nature, the content of the ingredients and the thickness of the coatings have the greatest influence on the physicochemical properties of heat-resistant coatings. The methods of obtaining a composition for heat-resistant coatings using a dissolver and a bead mill in various modes of operation were studied, which allowed us to develop a technological process for manufacturing heat-resistant paint and varnish material. The composition and technology of obtaining a final hydrophobic layer based on a suspension of aerosil HDK 12H and carbon nanoparticles in a fluorine-containing varnish LF 32LN was developed in order to obtain a complex heat-resistant, superhydrophobic and anticorrosive coating for the protection of metal products and its properties were investigated.

Heterocyclic compounds have an extremely important practical application, since many heterocycles are the basis of the most valuable medicinal substances, both natural (vitamins, enzymes, alkaloids, etc.) and synthetic biologically active compounds. The work mainly considers the most relevant directions for various purposes drugs search by modifying known bioactive natural, organoelement and framework compounds with 1,2-azole, oxazole, oxadiazole, thiazole, triazole, pyridine, pyrimidine heterocycles over the past 10 years. Chemical modification makes it possible to increase the water solubility of the compounds, which is important when choosing the pathways for the most rational drug introduction into the body, to reduce the toxicity of the corresponding substances, to increase the breadth of the therapeutic action, and also to give new valuable medicinal properties, thus significantly expanding their application in medicine and agriculture.