Home – Home – Jornals – Chemistry for Sustainable Development 2025 number 2

At present, in connection with the active development of the Russian Arctic, issues related to prevention and elimination of the consequences caused by disturbances of vulnerable northern ecosystems are becoming increasingly urgent. Soils deserve attention on the first-priority basis. On the one hand, soils are the basis of any terrestrial ecosystem, on the other hand, under the harsh conditions of the Far North, their self-restoration is slow, and effective reclamation measures are costly. In the work, the most common environmental problem of the northern territories of Siberia is considered: the pollution of soils with oil products. The properties of automorphous and hydromorphous organogenic, loamy, stony, sandy, and sandy loam soils widely occurring in the cryolithozone are investigated. It is noted that among soil properties, the greatest role in the fixation of oil products is played by total carbon content and cation exchange capacity, while the increased density of soils prevents the introduction and accumulation of oil products. Based on the analysis of literature data and statistical processing of own materials, recommendations on soil remediation at the sites contaminated with oil products to different extents are proposed.

Electrochemical properties of a cell with carbon highly porous electrodes and a solid polymer electrolyte based on polyurethane elastomer filled with a solution of an organic salt of N,N-methyl-propyl-piperidinium in N-methyl-2-pyrrolidone have been studied. The values of specific capacitance of the electrode material in contact with the polymer electrolyte, which reach 45 F/g, were determined by cyclic voltammetry (CVA) in the voltage range from -4.5 to 4.5 V and galvanostatic charge-discharge. Analysis of the dependence of capacitance on the potential sweep rate has shown that the main contribution to the capacitance is the pseudocapacitance due to surface electrochemical processes, the nature of which is still unclear. The CVA data are in good agreement with the data obtained by impedance spectroscopy. The obtained polymer solid electrolyte based on polyurethane elastomer can be used to create flexible polymer supercapacitors operating in a wide voltage range.

The possibility to increase the adsorption capacity of the sorbent Purolat-Standard, a cheap anthracite-based carbon material (CM), towards iron(II) ions was studied. Sulphuric acid, aminoethanoic acid, and their combination were used as modifiers. The effect of modification on the porous structure and surface state of the analysed sorbents was examined. It has been found that only treatment with sulphuric acid has a significant impact on the structural characteristics of the carbon material. A comparison of microphotographs of the samples before and after iron ion adsorption suggests its adsorption on the surface of macropores. It is shown with the help of X-ray diffraction analysis that the chosen modification methods do not change the phase composition of the sorbents. According to the data of spectroscopic studies, modification of sorbent samples leads to changes in the qualitative and quantitative composition of surface groups. The adsorption of iron(II) ions on the initial and modified samples of carbon material was studied under equilibrium conditions. It was found that using AEA as a modifier fundamentally alters the shape of the metal ion adsorption isotherms. The use of aminoethanoic acid as a modifying agent has been determined to strongly alter the shape of metal ion adsorption isotherms, which is due to different composition of functional groups on the sample surface and changes in the sorbent-sorbate interaction type. Using the Langmuir model and a modified Dubinin-Radushkevich equation for ion adsorption, the main adsorption characteristics were calculated. It is assumed that for the initial sorbent and the sample treated with sulphuric acid, as well as for the samples modified with aminoethanoic acid, in the case of low equilibrium iron concentration, adsorption proceeds via ion exchange. At higher equilibrium concentrations, the formation of iron ion complexes with the modifier is possible for the sorbents treated with the amino acid. It is established that the most promising sample for use as a sorbent for extracting iron ions from groundwater is the carbon material modified with both sulphuric and aminoethanoic acids (by sequential impregnation), which demonstrates the highest adsorption capacity.

The article presents the results of laboratory studies and pilot tests of compositions developed to eliminate steam and water breakthroughs from the rock mass into oil mine workings, and to fill voids in the rock mass in places where steam breakthroughs occur. The effect of individual components is investigated, which allows combining them to achieve the required properties of the composition. Laboratory studies have shown a high efficiency of compositions with two gelling components (polymer and inorganic) with the addition of a dispersed filler - basalt fibre. The compositions functions well within a wide temperature range (20-200 °C), are non-toxic and fireproof. Pilot tests of the developed composition for blocking steam breakthroughs into the mine were carried out in early 2024 at an experimental site of the Yaregskoye oil mine, using standard equipment available at the mine. The tests have shown applicability of the composition under oil mine conditions. The results of control observations show that the composition successfully plugs cracks and pores in the rock and in the concrete jacket, blocks steam breakthroughs, and retains its properties for a long time. It is planned to develop this area of experimental work, including refining the technology of injecting the composition to fill large voids, to determine the required composition volume, injection rate and location of injection points. In the future, it planned to test these compositions for surface steam injection wells.

A catalyst for the process of upgrading the straight-run gasoline fraction of oil was developed on the basis of pentasil zeolite by means of postsynthetic alkaline treatment, followed by the introduction of nanosized nickel powder. Three reaction-regeneration cycles were carried out, textural, acidic and catalytic properties of the initial and regenerated samples were studied, the amount of carbon compaction products and temperature range of their removal were determined. It is shown by IR spectroscopy that triplicate regeneration of carbonised zeolite catalysts does not change their crystal structure. It is shown by low-temperature nitrogen adsorption that multiple regenerations of the catalyst lead to an insignificant decrease in total specific surface area and total specific pore volume, with an increase in the specific surface area of mesopores. The temperature-programmed desorption of ammonia has been used to determine that the strength and concentration of acid sites in the regenerated samples decreased significantly, compared to the initial zeolite, only after the third regeneration. The activity of initial zeolite catalyst and its regenerated forms has been studied in processing the straight-run gasoline fraction of oil by the flow method in a reactor with a fixed catalyst bed, without using hydrogen-containing gas, at atmospheric pressure. It has been shown that after each reaction-regeneration cycle, the catalytic activity decreases slightly, but at the same time, the octane numbers of the resulting gasolines remain fairly high, and the yield of the catalysates increases. Using differential thermal analysis, it was determined that the number of regenerations has almost no effect on the amount of carbon compaction products on zeolite catalysts, as well as on the temperatures of decomposition peaks and termination of coke removal, but slightly reduces the temperature at which carbon deposits begin to burn out.

Results of studies on the conversion of gaseous hydrocarbon feedstock with different compositions into olefin hydrocarbons over zeolite-containing catalysts are presented. The results of catalyst testing indicate that zeolites modified with phosphorus and manganese exhibit high activity in the conversion of lower C2-C4 alkanes into olefin hydrocarbons. It has been determined that the P-containing zeolite catalyst has the highest dehydrogenating activity, and the Mn-containing zeolite catalyst is characterized by a higher overall activity. It is shown that significant conversion of the feedstock is observed within the temperature range of 600-650 °С, depending on the hydrocarbon chain length of the initial alkane molecule. For the P-containing zeolite catalyst, almost linear dependence of the yield of olefin hydrocarbons on the conversion of the initial С2-С4-hydrocarbons is observed. At the same time, for the Mn-containing zeolite, the dependence of the yield of olefin hydrocarbons on conversion is determined by the type of initial hydrocarbon feedstock. The acid and textural characteristics of the original zeolite and its modified samples were studied by temperature-programmed desorption of ammonia and low-temperature adsorption of nitrogen, and their distinctive features affecting the properties of the catalysts in the conversion of C2-C4 alkanes into olefin hydrocarbons were established.

The composition of fragments linked by sulphide bridges in the molecules of resin-asphaltene substances isolated from the liquid products of thermal destruction of asphaltene components of heavy high-sulphur oils from the Usinskoye and Ashalchinskoye fields in supercritical n-hexane is investigated using a complex of physicochemical methods (selective chemical degradation, IR spectroscopy, gas chromatography - mass spectrometry). The set of compounds identified in the products of C-S bond cleavage in the molecules of secondary asphaltenes and resins is largely identical to that identified in the products formed in the chemical destruction of the molecules of initial asphaltene components. They are represented by normal and branched alkanes, n-alkylcyclopentanes, n-alkylcyclohexanes, steranes, hopanes, phenylalkanes differing from each other in the position of phenyl ring in the carbon chain, diphenyls, naphthalenes, phenanthrenes, dibenzothiophenes, n-alcanoic acids, ethyl and isopropyl esters of n-alkanoic acids, and pentacyclic compounds of the oleanene series. A distinctive feature of secondary asphaltene molecules is the presence of n-alk-1-enes with an even number of carbon atoms and monocyclic aromatic hydrocarbons linked through sulphide bridges in their structure. The similarity of the set of compounds linked through sulphide bridges in the structure of initial asphaltenes and the products of their thermal decomposition under supercritical conditions is established, which suggests that the secondary asphaltenes and the resulting resins are fragments of the molecules of initial samples. These molecular fragments are linked in their structure through the least thermally stable functional groups - ether, disulphide and sulphide. The revealed differences in the pattern of molecular mass distribution for similar sulphur-bound compounds in the structure of secondary asphaltenes and resins allow us to assume that the resulting resinous components are located at the periphery of the asphaltene macromolecules of heavy high-sulphur oils.

Composite metal-carbon material based on technical carbon and metals (NiCo) was created, its physicochemical and catalytic properties in the oxidative desulphurisation of oil were studied. It has been established that the process of oil desulphurisation can be carried out under sufficiently mild conditions: temperature 60 °C, process time 90 min, catalyst content 1-1.3 wt%, the molar ratio of sulphur feedstock/oxidizer = 1 : 4. A more effective extraction system for extracting oxidised sulphur compounds from oil is a mixture of dimethylformamide (DMF) and water at the volume ratio of 9 : 1. In this case, it is possible to achieve a high degree of sulphur removal from oil - more than 70 %.

The structural organisation and chemical composition of asphaltenes of heavy oils from the sediments of the Paleozoic complex of the Volga-Ural and Timan-Pechora oil and gas provinces are studied using a mix of physicochemical research methods (electron microscopy, proton magnetic resonance spectroscopy, X-ray diffraction, chemical destruction, and combined gas chromatography-mass spectrometry). It is shown that the asphaltenes of oils from the Permian-Carboniferous and Devonian sediments, unlike the asphaltenes of Permian oil with their smooth surface, are characterised by a loose and porous surface, and smaller sizes of nanoaggregates forming a disordered tangled structure caused by the presence of a branched alkyl chain configuration, which hinders aromatic sheets stacking. The crystallites of asphaltene nanoaggregates of heavy oils are characterised by similar thickness, average diameter, and number of aromatic layers in their cluster core, as well as the distance between the aromatic layers and saturated fragments. It has also been determined that the mean molecule of asphaltenes of the Permian oil is larger in size due to the high content of aromatic and naphthenic cycles in the naphthenoaromatic system. A structural feature of the asphaltene components of Devonian oils is a more branched alkyl chain configuration. The structure of the asphaltenes of heavy oils includes fragments linked through sulphide, ether, methylene and polymethylene bridges. Among them, acyclic, mono- and polycyclic naphthenic and aromatic hydrocarbons, as well as sulphur- and oxygen-containing compounds have been identified. The same representatives of sulphur-bound and ether-bound saturated and aromatic hydrocarbons in the structure of asphaltene molecules of heavy oils are similar in composition, but differ from each other in molecular mass distribution. The results of the investigation expand our understanding of the structure of asphaltenes of heavy oils, which may be used to model their structure for developing new controlled methods for processing hydrocarbon raw materials.

Results of the study of a multifunctional acid composition GBС-F based on surfactants, polyol, an adduct of inorganic acid and carbonic acid diamide are presented. The dissolving ability of the acid composition in concentrated and diluted forms in relation to terrigenous and carbonate rocks, quartz and pyrite was studied. The use of the GBС-F composition was determined to cause different dissolving effects on the rocks of different types. It is shown that concentrated or diluted GBC-F affects the rocks to different extents: quartz and pyrite dissolved better in the diluted solution of the acid composition, while the use of concentrated GBC-F (the liquid commercial form) had the maximum effect when dissolving carbonate rock. In the study of terrigenous reservoir, rock solubility in the concentrate of GBC-F during the first hours was better than in the diluted solution, but after soaking for 24 h the values became equal.

The oxidation of cumene and its mixture with benzene by oxygen in the low-temperature barrier discharge plasma has been studied under the efficient removal of reaction products from the reactor, which makes it possible to avoid the deep oxidation of initial reagents and the formation of polymer deposits on reactor walls. Experiments were carried out in a setup with a plasmachemical reactor, under barrier discharge in the flow mode. The major products of cumene oxidation, namely acetophenone and dimethylphenylcarbinol, are formed with a total selectivity of up to 78 wt%. Cumene oxidation is not accompanied by the formation of phenol and its derivatives. Cumene conversion does not exceed 1.2 wt%. Oxidation of a mixture of cumene and benzene leads to the formation of cumene oxidation products (acetophenone and dimethylphenylcarbinol) along with the products of phenol oxidation (phenol and diphenols). It is shown that both aromatic hydrocarbons are oxidised independently in their mixture. Based on the research results and literature data, a probable mechanism of cumene oxidation in a barrier discharge is discussed and an attempt is made to simulate the process of its oxidation. The possibility to govern the oxidation of aromatic hydrocarbons in the low-temperature barrier discharge plasma by reactor temperature control is demonstrated.

The dynamics of the state of vegetation cover has been analysed in the hydrocarbon deposits of the Tomsk region, specifically Luginetskoye, Katylginskoye, Olenye, Lomovoye. The territory of the Oglatsky Nature Reserve was chosen as the background area. Based on satellite data from Terra/MODIS (Moderate Resolution Imaging Spectroradiometer), the average values of the NDVI vegetation index (Normalized Difference Vegetation Index) were calculated from June, 26 to July, 11 for the years 2012 to 2022. It has been found that the same trend in NDVI values is observed for the vegetation in the studied oilfields Luginetskoye, Katylginskoye, and Olenye: the maximum NDVI values were recorded in 2016, while the minimum values occurred in 2012. For the territory of the Lomovoye oilfield, the highest NDVI value was established in 2022, with the lowest in 2012. Overall, a positive trend in NDVI values was noted across all studied areas, with an average increase by 9.7 % from 2012 to 2022, indicating a stable (not suppressed) state of the vegetation cover of these territories.

The dependence of vegetation indices NDVI (Normalized Difference Vegetation Index) and EVI (Enhanced Vegetation Index) on the content of pigments in plants was studied at three sites with environmental disturbance: at the territory of diesel fuel spill, in the region of natural oil occurrence, and at a post-fire site. The studies have shown that the stability of plant species against pollution with petroleum products increases in the sequence: sedge < cereals < field horsetail < willow < moss. Determination of interrelation between remotely measured optical characteristics of the vegetation cover and the concentrations of pigments revealed a direct dependence of NDVI and EVI values on the concentrations of pigments in field horsetail and cereals, and inverse dependence for willow, moss, and sedge. In the region of natural oil occurrence under the conditions of pollution with oil, a substantial decrease in total chlorophyll content is observed for wild strawberry, artemisia, and thyme in comparison with the reference conditions. A decreased content of chlorophylls and carotenoids was detected at the post-fire site in padus, and an increased pigment content in dwarf elder, which provides evidence of the higher stability of dwarf elder to the action of high temperatures. The vegetation indices at the post-fire site are substantially lower than at the background (intact) site.

Analysis of the properties of the Bazhenov Formation metalliferous oil from the West Siberian oil and gas basin is presented During the development of these oil reserves, there is a danger of heavy metals (for example, vanadium and nickel) entering the environment during oil extraction, transportation and refining. The information from the database of the Institute of Petroleum Chemistry SB RAS (Tomsk) and the methods of statistical and spatial analysis of geographical information systems are used in the work. Based on the classification of hard-to-recover oil, deposits of the Bazhenov Formation with high and medium vanadium and nickel content have been identified. The distribution of oil from these fields over the depth of occurrence is shown. With an increase in the depth of occurrence, the concentration of metals in oil decreases by almost an order of magnitude. The lithological features of reservoir rocks have been revealed: metalliferous Bazhenov oil is mainly found in sandstones (86.2 % of oil samples) and in sandy-siltstone rocks (13.8 % of samples), which confirms that the reservoirs of the formation belong to the terrigenous type. The average values of reservoir parameters characterising filtration properties and the capacity of deposits are determined. To analyse metalliferous Bazhenov oil, a set of 68 oil samples from 33 fields in the West Siberian oil and gas basin was used. The results obtained in the study can be used in the development of new methods and technologies, and improvement of the existing ones, for the extraction and processing of metalliferous oil, taking into account environmental consequences.

Oil production from low-permeable reservoirs is an urgent and promising issue because of the depleted reserves of oil extracted using traditional procedures, both in Russia and abroad. The statistical analysis of porosity distribution in the sediments of the main oil and gas basins (OGB) of Russia is presented: the Volga-Ural, Timan-Pechora, North Caucasus and West Siberian. These basins have large reserves of hard-to-recover oil from complex formations with low porosity. Computer maps of the deposits with low-pressure reservoirs are presented. In the West Siberian basin, 15 deposits of this kind have been identified, 13 deposits in the Timan-Pechora basin, 63 in the North Caucasus, and the largest number of deposits is located in the Volga-Ural basin - 82. The great role of low-porosity rocks in the oil and gas potential of basins is shown, 80 % of the Russian reserves of low-porosity sediments are concentrated in the Volga-Ural basin. According to lithological characteristics, low-permeable reservoirs mainly belong to carbonate sediments, but the porosity of terrigenous rocks is higher, compared to carbonate deposits. The presence of reservoirs in various stratigraphic layers has been established, starting from the Cenozoic and ending with the Paleozoic, but most rocks belong to the Paleozoic age. The distribution of reservoirs with low porosity is analysed as the depths increase. It is shown that porosity decreases at great depths (over 5000 m) by a factor of 2-3, while the proportion of low-porosity sediments increases with depth, compared to medium-pored and highly porous rocks. In the future, at great depths, the role of low-permeable reservoirs as the sources of hard-to-recover oil will only increase.