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Bioremediation is the most relevant and popular method of soil purification from oil pollution, especially in the northern regions. The results of field experiments to study the influence of the age of oil pollution on the efficiency of microbiological remediation of soils on the territory of the former oil pipeline (southwest of Yakutia) are presented. Purification was carried out by introducing the biological preparation based on enrichment cultures of indigenous hydrocarbon-oxidising microorganisms, previously isolated from the soils of this territory. It was found that the degree of destruction of fresh pollution a year after bioremediation was 77.4 %, and for old 7-year-old pollution it was only 34.3 % (of the level that remained 7 years after the oil spill). For the first time, a decrease in the efficiency of bioremediation processes has been considered from the standpoint of the chain free radical mechanism of microbiological oxidation. In the absence of a readily oxidised substrate, specifically alkanes from n-C₁₂ to n-C₂₄, as well as 12,13-methylalkanes, which naturally degraded over 7 years, the initiation of oxidation slows down, and the addition of the biological preparation no longer allows achieving high purification efficiency. In addition, the formation of intermediate reaction products (high-molecular naphthenic-aromatic hydrocarbons) could inhibit the chain oxidation process due to the formation of stable intermediate radicals. The new formation of resins during bioremediation leads to hydrophobisation of soils and disruption of their water-air regime, which also could have a negative effect on the oxidative biodegradation of oil pollution. It has been shown that the method of bioremediation of oil-contaminated soils is most effective in the case of fresh oil spills.

To specify the region-associated mineral composition of the raw nut oil and seeds of the dwarf cedar pine (Pinus pumila) growing in an environmentally clean area of the Magadan Region, the content of 25 macro- and microelements in the raw materials was analysed. The results of the study allow us to conclude that the raw cedar nut oil is a source of the important trace elements - Zn and Cr. It has been determined that pine nuts can be considered as valuable food item because the inclusion of nuts in the diet in the amount of only 100 g can half satisfy the adult daily needs for Mg, P, Cu, Se, and Zn. This allows us to recommend raw cedar nut oil and pine seeds to be included into daily diet as a biologically active additive, which will replenish the deficiency of some vitally essential macro- and microelements for persons of any age when taken regularly in the amount not more than 1-2 teaspoons a day. No excess of the permissible levels of toxic elements in the studied samples was found, which confirms the environmental safety of the areas where the wild nut bush grows.

The In₂O₃-ZrO₂ and In₂O₃-CeO₂ catalysts for the hydrogenation of CO₂ into methanol were prepared and studied. The effect of oxide support on the physicochemical and catalytic properties of catalysts (CO₂ conversion, selectivity and productivity with respect to methanol) was studied using transmission electron microscopy, X-ray diffraction, temperature-programmed reduction by hydrogen, and temperature-programmed CO₂ desorption. It has been shown that these catalysts are active and selective with respect to methanol formation at 220-300 °C and a pressure of 40 atm. However, over time, the In₂O₃-CeO₂ catalyst becomes deactivated, while the In₂O₃-ZrO₂ catalyst shows stable performance for at least 10 h.

The properties of the In₂O₃-ZrO₂, In₂O₃-Ga₂O₃-ZrO₂ and In₂O₃-Co₃O₄-ZrO₂ catalysts for the reaction of CO₂ hydrogenation to methanol were studied. It has been determined that with an increase in indium oxide content, the catalytic activity passes through its maximum at In₂O₃ content 10 wt%. It is shown that the introduction of cobalt oxide into the catalyst increases the selectivity for methanol and increases CO₂ conversion. This is due to an increase in the number of oxygen vacancies on the surface of the catalyst. Promotion with gallium oxide, on the contrary, leads to a decrease in activity in the methanol synthesis reaction. Among the series of catalysts studied, In₂O₃-Co₃O₄-ZrO₂ exhibits the greatest activity, which achieves 11.1 % CO₂ conversion with 71 % selectivity to methanol at a pressure of 40 atm and 300 °C. It is also shown that this catalyst operates without a loss of activity for 30 h under these conditions.

The effectiveness of protection and rational use of water resources is reduced due to the difficulties of assessing their quality under the conditions of continuously changing controlled indicators and the uniqueness of such variability. The possibility of solving the arising problems by applying multivariate statistical methods of control, which are common in solving chemometric problems, is considered. By the example of the analysis of the Isakovskoye Reservoir waters (Lugansk People’s Republic), the influence of annual peaks of some pollutants on the increased volatility of the investigated time series was found. The double Schuchart control charts and cointegration tests allowed us to identify the periods of statistical stability of the process and to make an assumption about the active involvement of water pollutants in physical-chemical-biological processes. In particular, the existence of stationary linear combinations of a number of non-stationary (integrated) time series of controlled indicators has been found. The results obtained in the case study of a particular water body show that the methods of chemometrics offer opportunities to obtain the information for deeper understanding of the unique processes occurring in water bodies. This will make it possible to solve one of the main tasks of water-environmental management - to achieve a balance between the needs of water users and the possibility of water resources reproduction by taking optimal water management decisions depending on the current situation.

The content of phenolic compounds (flavonols, flavans (catechins), tannins), polysaccharides (pectins, protopectins), tetraterpenes (carotenoids), as well as the antioxidant and antiviral activity of Solidago canadensis L., Solidago virgaurea L., Bellis perennis L., cultivated in West Siberia has been investigated. The leaves and inflorescences of S. canadensis and S. virgaurea contain about 2 % of flavonols. The total tannin content varies in the inflorescences from 10.59 % (S. virgaurea) to 19.7 % (S. canadensis). The above-ground organs of S. canadensis are characterised by the higher content of catechins (up to 0.19 % in leaves) than S. virgaurea (up to 0.07 % in leaves). Leaves and inflorescences of the studied species of Solidago genus contain no more than 1 % pectins and 10 % protopectins. The concentrations of carotenoids in the leaves and inflorescences of S. canadensis are the same (about 0.1 %), S. virgaurea is characterised by a higher content of this group of compounds in the leaves (up to 0.2 %). The total content of catechins (up to 0.05 %), pectins (up to 2 %), protopectins (up to 7.0 %) and carotenoids (up to 0.01 %) in the leaves and inflorescences of B. perennis exhibit no significant differences. Flavonols are present in smaller amounts in the leaves (no more than 0.6 %), tannins in the inflorescences (no more than 6 %). The total content of phenolic antioxidants in the leaves and inflorescences of S. canadensis, S. virgaurea and B. perennis is within the range of 0.11–0.19 mg/g. The radical binding activity (determined by the DPPH method) of S. virgaurea (1.32–1.61 mg/mL) is two times higher than that of S. canadensis (3.05–3.58 mg/mL) on average. An aqueous-alcoholic extract from the leaves of S. virgaurea inhibits the reproduction of the avian influenza virus A/chicken/Kurgan/05/2005 (H5N1) (neutralization index (NI) is 4.75 lg) and the human influenza virus A/Aichi/2/68 (NI is 4.50 lg).

The problem of neutralising liquid solutions containing hexavalent chromium compounds is considered. The advantages, disadvantages and features of the application of basic methods for neutralising chromium-containing waste, non-traditional approaches and combined technologies are analysed. A readily feasible reagent method is presented for purifying concentrated and dilute solutions from chromium by treatment in two stages: reduction of hexavalent to trivalent chromium using ferrous sulphate or sodium sulphite as reducing reagents, and precipitation of chromium hydroxide. An installation is described in which electrolytes, rinsing and waste water from galvanic production were neutralised. A practical approach to the problem of neutralising the inhibitor solution is proposed, which is similar to the methods used for processing chromium-containing waste from galvanic production. A technological process has been developed for the reagent treatment of an inhibitor with a high concentration of chromates in solution (up to 40 g/L) in one stage by the direct precipitation of poorly soluble chromates. Barium chloride was used as the precipitant. To implement the technology, a schematic diagram of the installation was developed, and appropriate equipment was selected. As a result of processing the inhibitor, waste water, heavy precipitate of barium chromates are formed, which can be used in the future as a raw material, and sludge, which is a non-recyclable waste. Experimental processing of the inhibitor solution shows that the proposed method is effective, economically feasible, readily implementable under industrial conditions, it allows for high purification degree with low consumption of reagents, and reduces the amount of precipitates formed, which confirms the practical significance of the results obtained.

The high-strength nanocomposite cryogels based on polyvinyl alcohol (PVA) and carbon nanotubes (CNTs) have been synthesised and studied. To overcome the problems related to CNTs agglomeration in polar solvents, which limits their uniform distribution over the polymer matrix, cryogel composition was optimised to achieve high strength characteristics. To obtain uniform CNT dispersions, homogenisation in solvents (water, dimethyl sulphoxide (DMSO) and a mixture of DMSO/water = 80 : 20 by volume) in combination with ultrasonic treatment was used. During the experiment, cryogel samples were stretched uniaxially, which allowed us to obtain the ultimate strength values for each sample. Data processing was performed using STATISTICA 10 software. Using regression modelling, the Dependences between the ultimate strength of nanocomposites and synthesis parameters (the concentration of initial PVA solution, its molecular weight, water content in the solvent, and the concentration of CNTs) were established using regression modelling. The obtained regression equation was adequate with respect to Fisher’s criterion, and determination coefficient was R² = 0.81, which confirms the accuracy of the model and its applicability for predicting the strength characteristics of cryogels. In addition to regression analysis, the dependences of the Harrington desirability function on synthesis parameters were analysed. This approach allowed us to identify optimal components ratio for obtaining PVA/CNT nanocomposite cryogels, which significantly increased the efficiency of developing materials with high strength properties. The results of the study emphasise the importance of taking into account various factors when optimising synthesis conditions and also offer new prospects for further research in the area of polymer composites.

The processes involved in obtaining iron-free X-ray amorphous aluminosilicate raw material of the required composition from the ash and slag waste (ASW) from the combustion of brown coal of KAFEC are investigated. Carbon thermal reduction during ASW melting is used to extract iron and its compounds. The distribution of elements - iron (Fe²⁺, Fe³⁺, Fe⁰, Fe^tot), sulphur (S) and carbon (C) - in the metal (magnetic) and silicate (nonmagnetic) fractions at different temperatures of ASW heating is shown. The equations describing the temperature dependence of the standard change of Gibbs energy for the reactions of the reduction of iron oxides are presented. The effect of silicon carbide, formed in the silicate fraction of the melt, on the recovery of iron oxides to metal iron and the resistance of foam formed due to the reducing gases are discussed. The introduction of the melt into water changes the morphology and leads to the formation of foamed heat-insulating material. Normalization of the charge during melting allows obtaining foamed materials of the required composition.

Metal matrix composite powders based on titanium carbide with titanium and high-speed steel as binders were studied by means of X-ray diffractometry, scanning and transmission electron microscopy. The composite powders were obtained by crushing the cakes formed as the products of self-propagating high-temperature synthesis (SHS) from titanium, carbon (black carbon) and HSS powder mixtures, followed by mechanical treatment in a planetary ball mill Aktivator-2S. It was stated that disintegration rate depends on metal binder content in the SHS product. To obtain the powder suitable for use in additive technologies, SHS powder of titanium carbide was ground preliminarily and then subjected to additional treatment in mixture with Ti powder in the planetary ball mill. As a result, the powder mixture consists of equiaxial granules containing fine TiC particles uniformly distributed in the Ti matrix. Results of the studies of the microstructure of samples obtained by means of selective laser melting (SLM) and electron beam melting (EBM) provide evidence of the advantages of SLM technology over EBM.