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We have studied an Upper Devonian volcanoterrigenous carbonate complex in the north of the Kuznetsk trough. The northern part of the complex is subducted beneath the Meso-Cenozoic sedimentary cover of the West Siberian geosyneclise. Analysis of sedimentologic processes, the nature and specific composition of pyroclastic impurity, and the petrographic and chemical compositions of sedimentary rocks makes it possible to reconstruct the facies and geodynamic settings. It is shown that the fine-grained pyroclastic material is predominantly of andesite composition, whereas felsic and mafic volcanic components are subordinate. In the transition from the lower Frasnian to the Famennian, the content of felsic pyroclastic component increases. The geodynamic settings of the shelf and continental slope of the Siberian continent up to its base have been established. Facies analysis shows that the slope is west-facing (in the present-day coordinates). The deposits accumulated mainly in the basin; these are fine-grained terrigenous rocks, fine-grained limestones, slope landslide breccias and olistostromes, turbidites, and “conglomerate-like limestones” (paleoseismites). According to the geochemical data, the Late Devonian paleogeodynamic setting was stable and corresponded to the setting of an active continental margin. Arid to semihumid lithogenesis has been established. Marine sediments formed in an oxidizing environment with good water aeration.

Structural and lithological comparison of intraformational plicative liquefaction deformations (convolutions) in Late Quaternary lacustrine complexes of the Baltic Shield (sediments of small glacial lakes) and the Tien Shan (sediments of a large stationary basin in the Issyk-Kul depression) is carried out in order to clarify their genesis. These regions have sharply different levels of seismotectonic activity, which makes it possible to most fully determine the role of a seismic factor in the formation of bedding disturbances. Convolutions in the Baltic Shield are represented by load casts, flame structures, pseudonodules, and regular folds with more pronounced anticlinal bends. It is shown that convolutions occur here only in the most liquefied soils (siltstones and fine-grained sands) with low cohesion and fluid permeability in the case of unstable (increased density and coarsening of the sediment from bottom to top) or neutral (homogeneous composition) stratification of weakly consolidated sediments, and the ratio of the widths of the synclinal and anticlinal parts of the folds ( K _syn) for these structures is 1.0-7.5. These signs point to the formation of disturbances because of a spontaneous instability or an instability initiated by weak mechanical influences in the sedimentary stratum under conditions of a normal vertical gradient of the sediment viscosity. Deformations in the second region are structures typical of the Baltic Shield, columnar structures of deep interpenetration of layers, diapirs, and clastic dikes. There are also flexural folds with K _syn ≈ 1, which formed at a higher degree of sediment consolidation than the actual liquefaction structures. The convolutions of the Issyk-Kul depression are developed not only in sand-silty sediments but also in relatively lowly liquefied soils (clay, gravel, and pebbles). These structures formed under both unstable and stable density stratification of the sediment (for example, clay-on-sand), and K _syn = 0.3-2.5. Thus, the formation of convolute structures in the Issyk-Kul depression is impossible without strong dynamic impacts on stratified sediments during their accumulation. The results obtained make it possible to substantiate the predominantly diagenetic (convective and landslide) genesis of convolutions in the lacustrine complexes of the Baltic Shield and the seismogenic genesis in the limnogenic deposits of the Tien Shan. A number of new criteria for identifying seismites are proposed, which determines the practical significance of the study.

Bottom sediments of lakes are regarded as one of the most informative continental facies used to reconstruct environmental changes in lake catchments. They usually contain a high-resolution and continuous record of geologic events, the knowledge of which is important for understanding the evolution of sedimentary processes and landscapes under the influence of climatic changes and the impact of short-lived catastrophic processes. The southwestern Baikal region (the Tunka rift and its East Sayan mountain framing) is replete with lakes of different geneses and morphologies. Recent fieldworks have allowed a multiproxy study of the lacustrine sediments of several lakes of the Oka and Tunka regions. The results demonstrate that there were no glaciers in the foothill plain of the Tunka rift valley earlier than 14,800 cal yr BP. On the Oka plateau, within the East Sayan high-mountain zone, deglaciation started somewhat earlier than 13,800 cal yr BP. The grain size, petromagnetic, and physical properties of the lacustrine sediments point to a general weak hydrodynamics throughout the 13,800 yr sedimentation history in Lake Khikushka. However, a gradual reduction in fine fractions from base to top of the lake section suggests a gradual drawdown of the water level following the change of the water source from glacial melt waters to atmospheric precipitation. Biogenic silt accumulation in Lake Khikushka started parallel with the onset of the Holocene ~11,700 yr BP, suggesting a quick response of the natural environment of the lake basin to major global climatic changes. The short-term episodes of enhanced hydrodynamics in Lake Khikushka ~9000, 8200, 6500, and 2000 yr BP confirm the high sensitivity of the lake geosystem to climatic changes, not only on a millennial but also on a shorter-time scale. The characteristics of the sediments of Lake Engarginskoe are evident of lacustrine-alluvial sedimentation in the reservoir in the Early and Middle Holocene. New data on the grain size and petromagnetic parameters of the lacustrine sediments from two lakes located within different climatic belts of East Sayan show their high potential for a wide range of paleoecological reconstructions.

Coal fires are a phenomenon that can be observed worldwide in areas where rocks containing coal seams are exposed and can pose major environmental threats. A coal fire can begin through spontaneous combustion when coals are exposed to dry and oxygen-rich near-surface conditions. Burning, depending on the temperature of heating, causes baking or even melting of the surrounding rocks and the formation of different types of combustion metamorphic rocks. In Northwestern China, coal fire occurrences are concentrated at the edges of the sedimentary basins or at the margins of orogenic belts, where coalrich units were exposed owing to the Indo-Eurasian collision. On the northern margin of the Tianshan range, evidence of coal fires is widespread in the Jurassic sedimentary units containing coal seams which outcrop along the Central Asian Orogenic Belt. In some cases, coal fires are active and can be linked to ongoing mining activity, but outcrops of combustion metamorphic rocks not associated with fires are also found and are indicative of past burning events. We examine combustion metamorphic rocks outcropping in the Toutunhe River valley (Liuhuangou area, Xinjiang, Northwestern China). Combustion metamorphic rocks in the study area were mapped and classified according to their morphological and mineralogical characteristics. Outcrops are exposed at various heights on the valley flanks, which are characterized by the presence of multiple levels of fluvial terraces. These terraces are indicative of the phases of erosion and deposition of the Toutunhe River and testify to tectonic uplift. The investigation of the stratigraphic and crosscutting relationship of combustion metamorphic rocks with terrace deposits and apatite fissiontrack dating made it possible to determine that at least four phases of coal fire activity occurred from late Miocene to Quaternary. The first and oldest burning phase dates back to 10 ± 1.3 Ma and terminated prior to 2-3 Ma; the second was active before ~550 ka; the third had terminated by ~140 ka; the fourth began later than ~5.7 ka. The relationships between combustion metamorphic rocks and fluvial terraces further suggest that coal fire ignition/extinction in the area since the Miocene have been linked to the interplay between the uplift of the Central Asian Orogenic Belt and the phases of fluvial erosion and deposition in interglacial periods.

This paper presents conventional and innovative technologies for wastewater and industrial solution purification from Ni²⁺ ions and accompanying non-ferrous metals. Several methods including sorption, extraction, flotation, chemical, electrochemical, membrane and microbiological separation of impurities from the liquid phase are introduced. Chemical methods involve nickel deposition in the form of insoluble compounds (hydroxide, carbonate, bicarbonate, sulphide, dimethylglyoximate), or metal powder by adding certain reagents. Carbon, aluminosilicate and some other inorganic materials in initial and pre-modified forms, as well as weakly acidic, strongly acidic, weakly basic, including chelate ion-exchange resins and fibres are used for sorption. The extraction of nickel ions from the liquid phase is carried out with the derivatives of organophosphorous, carboxylic acids, as well as with materials that combine the properties of solid sorbents and liquid extractants. Nanofiltration and reverse osmosis are the most relevant methods among the membrane purification methods. Foam separation of nickel ions during flotation is carried out using anionic and nonionic surfactants. Electrochemical methods include electrocoagulation, electroextraction, electroflotation, and electrodialysis using soluble and insoluble electrodes, as well as galvanic coagulation without connection to external power. Living and non-living biomass of some species of bacteria, fungi, algae, as well as their complex mixture in the form of activated sludge can be deployed for microbial extraction of nickel from aqueous media. The above purification methods are considered on the basis of case studies, both generally applicable and specific ones. Their advantages and disadvantages are briefly described.

The currently widespread methods of processing fuel oils obtained during the primary separation of oil are complex multistage processes, including preliminary vacuum distillation and subsequent cracking of the resulting vacuum gas oils, as well as the oxidation of residual tar into bitumens. For small-scale industries, such processes are costly and, in some cases, unprofitable. The article proposes a technology for thermolytic processing of fuel oil over a tin-lead melt in a semi-continuous reactor. The main advantages of the proposed technology are low process temperature and pressure close to atmospheric, as well as almost complete elimination of the formation of carbon deposits on reactor walls. The reported results describe experiments on thermal cracking of fuel oil carried out according to two kinds of destructive distillation: the classical version, and the version involving a tin-lead melt. It is shown that during destructive distillation on a tin-lead melt, deeper cracking occurs in comparison with classical destructive distillation. The content of gasoline fraction (IPB-180 °С) and diesel fraction (180-360 °С) in thermal gas oil obtained by means of classical destructive distillation is higher than in thermal gas oil obtained by destructive distillation on tin-lead melt, while the content of fractions boiling above 360 °C is lower. The group composition, density and dynamic viscosity of thermal gas oils differ insignificantly. For thermal gas oil obtained over a tin-lead melt, a slight decrease in sulphur content is observed. Analysis of thermal gas oils for tin and lead showed their absence. Thermal gas oils have a high content of aromatic compounds, which makes them a promising raw material for needle coke production. Multiple analysis of the tin-lead alloy after the completion of the process showed that the alloy was free from mechanical impurities present in the fuel oil, it also did not contain coke released during thermolysis, and the mass of the alloy remained constant, which means that in this case the alloy plays the role of an effective heat carrier, which makes it possible to deepen fuel oil thermolysis.

The methods of manufacturing the sintering additives to coal charges from the vacuum residues of visbreaking tar, one of the most widespread and large-tonnage products, are considered. The starting raw material was subjected to deep vacuum distillation on a laboratory unit and thermal oxidation in a batch reactor. Experimental samples of sintering additives were obtained, and the possibility to produce sintering additives of petroleum origin on this basis was investigated. The physicochemical characteristics of the obtained products were determined; the possibility of their transportation, crushing, mixing and use instead of sintering coal grades in coal coking charges was assessed. A comparison of the obtained sintering additives was carried out for different production methods: an increase in the extent of tar conversion in visbreaking, deep vacuum distillation of the visbreaking residue, and oxidation of the visbreaking vacuum residue. The possibility of the industrial production of sintering additives from visbreaking residues was evaluated on the basis of research results.

Results of the studies of powder and structural composites (plates) based on low-density polyethylene (LDPE 15803-020 and LLDPE 6101RQ) and ultra-high molecular weight polyethylene (UHMWPE from Braskem company) and inorganic additives (SiC, TiO₂, CaCO₃, SiO₂) within concentration range 0.05-70 wt. % are presented. It is established that ultradispersed inorganic particles promote a decrease in the amount of the crystalline phase of polymers and an increase in wear resistance for the samples: UHMWPE (containing 7 wt. % SiC ( S _sp = 10 m²/g)) - by a factor of about 150; LDPE 15803-020 (20 wt. % SiC ( S _sp = 6-10 m²/g)) - by a factor of 2-2.5. For LLDPE 6101RQ samples with the low additive content (0.05-5 wt. % ТiО₂, SiO₂, CaCO₃), tensile strength increases by 7-24 %, мodulus of elasticity (along the axis) increases by a factor of 1.2-1.4, and relative elongation at fracture decreases within the range of 13.5-38.0 %. The maximal increase in tensile strength is observed for samples containing 20 wt. % SiO₂ and 50 wt. % ТiО₂ (by 38.5 and 43.6 %, respectively), while relative elongation at fracture decreases 2.8 and 3.9 times, and мodulus of elasticity increases by a factor of 1.9 and 2.0, respectively. Comparative data on the oxygen permeability of the plates, with different methods for the initial components’ mixing, show that samples prepared by mixing the polymer with inorganic additives in a mixer (the amount of additives 5 and 20 wt. %) gave a decrease in oxygen permeability within 5.6-11.2 %, while the samples prepared through mixing in a planetary mill activator, AGO-3, showed a decrease in oxygen permeability in the range of 16.8-28.7 %, compared to the original sample.

The catalytic properties of ZSM-5 type zeolites modified with copper, zirconium and boron in the process of obtaining high-octane gasoline from the straight-run gasoline fraction of gas condensate have been studied in a flow-through installation at atmospheric pressure without hydrogen within the temperature range 350-430 °C. Cracking and aromatization of hydrocarbons mainly take place on non-modified HZSM-5 zeolite; with an increase in reaction temperature from 350 to 430 °C on HZSM-5, an increase in the content of aromatic hydrocarbons (from 10.8 to 16.9 mass %) and a decrease in the yield of liquid hydrocarbons (from 68.6 to 60.8 mass %) is observed. Modification of HZSM-5 zeolite with copper significantly changes the content of high-octane components in the catalyzate. An increase in copper concentration in HZSM-5 up to 2.0 mass % leads to an increase in the ability of the catalyst to provide isomerization and aromatization. At the optimum temperature (380 °C), the content of isoparaffinic and aromatic hydrocarbons in the catalyzate increases up to 36.8 and 24.6 mass %, respectively. An increase in the concentration of copper in HZSM-5 up to 3.0 mass % promotes an increase in the aromatization ability of the catalyst. Modification of the catalyst 2 % Cu/HZSM-5 with boron in the amount of 0.5-1.0 mass % has a small effect on its isomerization and aromatization properties, but significantly increases the yield of liquid products. It is found that the modification of the catalyst 2.0 % Cu-1.0 % B/HZSM-5 with zirconium in the amount of 0.5-1.5 mass % significantly increases the content of isoparaffinic hydrocarbons in the catalyzate (42.1-43.5 mass %). The highest activity is exhibited by the bimetallic catalyst consisting of 1.0 % Zr-2.0 % Cu-1.0 % B/HZSM-5, which allows obtaining the gasoline fraction with 88-94 octane number according to the research method. The addition of boron in the amount of 1.0 mass %, followed by the introduction of zirconium and copper, makes it possible to increase the duration of catalyst operation by up to 200 h. With respect to the content of isoparaffinic and aromatic hydrocarbons and benzene, the gasoline fraction corresponds to the Euro-4 and Euro-5 class. The possibility of refining low-octane straight-run gasoline fractions in the presence of a bimetallic catalyst under unconventional conditions without hydrogen supply to the reaction zone at atmospheric pressure is demonstrated.

As a result of sedimentation, suspended particles carry chemical pollution from the surface layer of water into bottom sediments, playing a significant role in waters’ self-purification from mercury. For the purpose of establishing the features of mercury distribution in the surface water of coastal and open-sea areas and concentrating it in the suspended matter, mercury concentrations were measured in water sampled in different seasons of the years 2018-2019 from the surface water layer of the Black Sea, and empirical dependencies of the parameters of mercury concentrating by the suspended matter on the seasons and depths of the water areas were determined. It is demonstrated that dissolved mercury forms dominated in the Black Sea during the period under investigation, regardless of the seasons. The concentration of dissolved mercury form in the water of the Black Sea varied from 10.0 to 130.0 ng/L, and the average concentration was 54.9 ng/L. The coefficient of mercury accumulation by suspended matter (K_ss) was determined, which varied within the range (0.01-3.33)•10⁶. The values K_ss > 10⁶ provide evidence of the high concentrating capacity of suspended matter in sea water and prevalence of sedimentation over other biogeochemical mechanisms of water self-purification. The formula for calculating the percentage pool of mercury in suspended matter was analysed. The values of the percentage pool of the suspended form of mercury were obtained, ranging from 3.2 to 75 % of the total mercury content in the surface water of the Black Sea for its coastal and open water areas in different seasons of the year.