Home – Home – Jornals – Advanced Search

The issues of climate warming and permafrost thawing are considered. A procedure for assessing the Arctic landscapes thawing based on the calculation of the normalized differential snow index (NDSI) is proposed. The factual material over the data of the global permafrost monitoring network is presented. Monitoring studies have shown that according to the results of NDSI calculation, abnormally early snowmelt was detected in 5 cases out of 23 years of observation at the Urengoy meteorological station and in 4 cases out of 23 years at the Tarko-Sale meteorological station. The absence of snow was observed during the indicated period in 13 cases at the technogenic sites of the Urengoy field, and in 8 cases at the Tarko-Sale field. With early snowmelt, the snow index NDSI decreases, and the depth of the seasonally thawed layer increases at the sites of the Urengoy field. The NDSI index can be used directly in assessing the duration of snow cover and early snowmelt, and indirectly in studying the depth of seasonally thawed layer. The results obtained are important for predictive estimates of the rate and extent of thawing and permafrost deformation, and for the prevention of emergency situations in the oil and gas complex.

To enhance oil recovery and intensify the development of fields with hard-to-recover reserves, including the deposits of high-viscosity oils, acid oil-displacing compositions with prolonged action have been developed on the principles of green chemistry using the method of deep eutectic solvents (DES). These compositions are based on surfactants and an adduct of inorganic acid, polyol and carbamide. As a result of experimental studies of acid-base equilibria in three-component systems with donor-acceptor interactions “boric acid - carbamide - polyol (glycerol, pentaerythritol)”, which are DES, the optimal compositions and concentration ranges of the components in acid compositions were determined. The results of laboratory studies and pilot tests of enhanced oil recovery technology with the use of acid compositions are presented. The compositions are compatible with mineralized formation waters, have a low freezing point ((-20)-(-50) °С) or a solid commodity form, low interfacial tension at the boundary with oil, are applicable in a wide temperature range (from 10 to 200 °C), provide effective oil displacement and prolonged impact on the formation. The acid GBA composition showed high efficiency under field conditions during pilot work in the experimental areas of the Permian-Carboniferous deposit of high-viscosity oil of the Usinsk oil field, developed under natural conditions and under thermal steam exposure, and was recommended for industrial use. The technology is environmentally friendly and technologically efficient. The industrial use of technologies for enhanced oil recovery and intensification of oil production is promising, which will make it possible to extend the profitable operation of fields at a late stage of development, to involve the fields with hard-to-recover oil reserves into development, in particular the deposits of high-viscosity oils, in a wide range of climatic conditions, including the northern regions and the Arctic.

The results of a comparative gas chromatographic - mass spectrometric (GC-MS) analysis of the composition of saturated and aromatic hydrocarbons, as well as heteroorganic compounds in petroleum oils isolated from a number of crude oils and natural bitumens, before and after selective chemical cleavage (chemolysis) of C-S and C-O bonds of sulphide and ether/ester bridges, respectively, are presented. The revealed difference in the structural-group and molecular composition of some types of compounds before and after chemolysis indicates that alkanes, alkyltrimethylbenzenes, naphthalenes, phenanthrenes, tetra- and pentacyclic aromatic hydrocarbons, and dibenzothiophenes are present in oils not only as molecular entities, but, partially, as structural fragments linked via sulphide and ether/ester bridges with other fragments in complex high-molecular entities. Ester-bound high-molecular С₂₀-С₃₀ homologues predominate among the bound alkanes. The proportion of C₁₃-C₁₆ homologues among alkyltrimethylbenzenes decreases after chemolysis. Chemolysis is accompanied by an increase in the proportion of С₃-С₄ naphthalenes in petroleum oils. The ratio of homologues among phenanthrenes changes after chemolysis: as a rule, the unsubstituted compound predominates over homologues. The ratio of fluoranthene and pyrene to benzanthracene and chrysene increases among tetracyclic aromatic hydrocarbons. The main trend in the changes in the composition of dibenzothiophenes after chemolysis is a sharp decrease in the proportion of unsubstituted homologue.

New methods of zeolite HZSM-5 modification with bismuth compounds are proposed. The choice of bismuth as a modifying agent is due to the systematisation and generalisation of the available literature data and experimental results of studying the chemistry and synthesis of bismuth compounds of various compositions. Phases in the resulting bismuth-containing zeolite systems were identified by X-ray phase analysis, and the state of bismuth in chemical compounds was determined. The number and strength of acid sites in the original and modified samples were determined by the method of temperature-programmed desorption of ammonia. The catalytic activity of zeolites was studied in the process of hydrogen-free processing of straight-run gasoline fraction of oil into high-octane gasolines. The effect of modification methods and process temperature on the structural-group hydrocarbon composition, the yield of gaseous and liquid reaction products was studied, and the octane numbers of the resulting gasolines were determined. It is shown that over the bismuth-containing zeolite catalysts, in comparison with unmodified zeolite, the yield of the target product, high-octane gasoline containing a smaller amount of aromatic hydrocarbons, increases, which makes it more environmentally friendly. It has been established that the production of high-octane gasolines that meet modern requirements for motor fuels is possible over modified zeolites within a wider process temperature range. Based on the studies performed, Methods for modifying the HZSM-5 zeolite with bismuth are proposed on the basis of the studies performed. The proposed methods make it possible to improve the efficiency of the catalyst in the process of upgrading the straight-run gasoline fraction of oil.

The content and composition of organic compounds in the bottom sediments of rivers and in soils sampled at the Arctic territory affected by diesel fuel spill were studied by gas chromatography-mass spectrometry. The composition of diesel fuel was studied. It was found that the groups of compounds characteristic of diesel fuel - n -alkanes, polycyclic aromatic hydrocarbons, alkylbenzenes and trimethylalkylbenzenes, sesquiterpanes, steranes, and hopanes were found mainly in the samples taken downstream at a distance of 0.5-20 km from the pollution source. The highest concentration of identified compounds was detected in bottom sediments and soil sampled at a distance of 20 km from the spill, which is associated with the structural features of the riverbed and bank line. In the samples taken at more remote sites (40-90 km), the traces of diesel fuel components were found only in bottom sediments.

Ferulic acid (FA) is a phenolic substance widespread in plants and exhibiting a wide range of potential therapeutic effects, such as antimicrobial and anti-inflammatory, and useful in the treatment of diabetes, lung and cardiovascular diseases. Methanol extracts from the fresh leaves of 40 species from the Lamiaceae family growing in the outdoor collections of the Botanical Garden of the Komarov Botanical Institute of the Russian Academy of Sciences (BIN RAS, Saint-Petersburg) and the experimental station "Otradnoye" BIN RAS (Leningrad region) have been investigated. Ferulic acid was detected in 18 species under investigation, related to the subfamilies Lamioideae Harley ( Betonica grandiflora Willd., Galeobdolon luteum Huds., Lamium album L., Sideritis taurica Steph. ex Willd., Stachys byzantine K. Koch) and Nepetoideae Kostel. ( Clinopodium vulgare L., Hyssopus officinalis L., Lavandula angustifolia Mill., Meechania urticifolia (Miq.) Makino, Melissa officinalis L., Mentha piperita L., Monarda didyma L., Nepeta bucharica Lipsky, Nepeta grandiflora M. Bieb., Origanum vulgare L., Prunella laciniata (L.) L., Salvia desertum L., Salvia officinalis L., Thymus serpillum L.). Ferulic acid was not detected in the representatives of Ajugoideae Kostel. и Scutellarioideae Caruel subfamilies. For 7 species, FA was detected for the first time. The content of FA in the representatives of Lamiaceae subfamily varied within a broad range from 0.01±0.00 mg/g ( Meechania urticifolia ) to 6.68±1.30 mg/g ( Melissa officinalis L.). The high ferulic acid content was established in the Nepetoideae subfamilty in the species Melissa officinalis (6.68±1.30 mg/g) and Origanum vulgare L. (6.07±1.90 mg/g).

The kinetics and mechanism of hydrogen evolution on the FeSi₂ electrode in 0.25-1.0 M NaOH solutions have been studied by polarisation and impedance measurements. The cathodic polarisation curves of iron disilicide in the studied solutions are characterized by a Tafel region with constants a and b equal to (-0.78)-(-0.72) and (-0.133)-(-0.128) V, respectively. The impedance spectra of FeSi₂ at the potentials of the Tafel region represent a capacitive semicircle with a displaced centre, which corresponds to an asymmetric maximum in the graph of phase angle dependence on the logarithm of the alternating current frequency; the magnitude of the electrode impedance in all solutions changes in accordance with the course of the polarization curves. To describe the hydrogen evolution reaction on iron disilicide, an equivalent electrical circuit was used, the Faraday impedance of which consists of series-connected charge-transfer resistances and a parallel circuit responsible for the adsorption of atomic hydrogen on the surface and its diffusion into the depth of the electrode material; the circuit also includes the electrolyte resistance and the double-layer capacitance impedance, which is modeled by a constant phase element. It is shown that the results of polarization and impedance measurements for the FeSi₂ electrode are in satisfactory agreement with the discharge-electrochemical desorption mechanism, in which both stages are irreversible and have unequal transfer coefficients; for adsorbed atomic hydrogen, the Langmuir adsorption isotherm is satisfied; simultaneously with the reaction of hydrogen evolution, the reaction of hydrogen absorption by the electrode material proceeds with diffusion control. It has been found that iron disilicide in an alkaline electrolyte is characterised by the low overvoltage of hydrogen evolution, and it is a promising electrode material for the electrolytic production of hydrogen.

High-molecular oil fractions exhibiting the initiating effect, nontypical for these oil objects, on the model reaction of cumene radical oxidation were investigated by means of microcalorimetry. It is shown for some objects that the initiators appear in the high-molecular fractions of oil in the course of their isolation from native oils by n-hydrocarbons. An insignificant correlation is established between the content of nickel, vanadium, and vanadylporphyrins and initiating activity. The initiators have been found in freshly isolated ‘acid resin’ fractions, which lose their initiating ability during storage due to chemical condensation processes. This method may be considered as a test for the content of inhibitors or initiators of radical oxidation in oil objects.

Intense coal mining at the territory of our country, related to the growing amounts of exported fuel, promotes the development of logistic infrastructure but at the same time causes a worsening of the environmental situation near coal mining enterprises. One of the ways to cope with the surfaces that generate dust, in particular fine coal dust particles, is surface treatment with hydrophobising organosilicon emulsion. However, the problem connected with enhancing the hydrophobicity of coatings formed by the emulsion has not been solved yet. This parameter is estimated by determining the wetting angle. The efficiency of modification and the coalescing ability of various additives in the aqueous emulsions of organosilicon liquid GKZh-94 are evaluated in the present work from changes in the wetting angle. The dependences of film wettability changes on the modifying and coalescing agents, and on their amount in the emulsion are demonstrated. The dependences of wetting angle changes on the amounts of the modifying and coalescing agents in the emulsion are plotted on the basis of the polynomial approximations of functions. It is established that preliminary modification of the emulsifier causes an increase in the hardness of polyvinyl alcohol, which hinders coalescence of particles in the emulsion. It is also determined as a result of a comparative analysis that the best wetting angle values are detected for the emulsions with the emulsifier modified with a small amount of glutaric aldehyde, with the high concentration of ethylene glycol as a coalescing agent. The use of glutaric aldehyde in the amount of 0.1-0.25 % and ethylene glycol in the amount of 3-6 % of the total mass of emulsion will allow an increase in the wetting angle of the formed coatings to 125°.

Currently, the chemical nickel plating process is one of the most popular electroplating methods compared to others due to a number of advantages. However, the production process generates a significant amount of spent chemical nickel plating solutions, which poses a threat of environmental pollution. To solve this problem, the possibility of regenerating the spent solution of chemical nickel plating from one of the industrial enterprises of Udmurtia by the reagent method was studied. Sodium carbonate was chosen as the precipitant for nickel ions, the amount of which was determined from potentiometric titration curves; the most complete precipitation of nickel ions occurs at pH 10. It has been established by IR spectroscopy that nickel hydroxide salts are formed as a result of the interaction of the spent electrolyte with the precipitant. The results of thermogravimetric and differential thermal analysis of the precipitate showed three endothermic effects: at temperatures up to 100 °C, it corresponds to dehydration; at 280±10 °C - to the removal of a part of chemisorbed water and carbonates; at 420 °C - to the final removal of water. As a result of heat treatment of the hydroxocarbonate precipitate, a black fine powder of nickel (II) oxide is obtained, the IR spectrum of which has a set of bands characteristic of this compound. Two variants of the technological scheme for the regeneration of spent electrolytes for the preparation of initial working solutions for chemical nickel plating from nickel (II) hydroxocarbonate and nickel oxide are proposed. The quality of the obtained solutions was checked by applying a nickel coating on brass products. The thickness of the coating was measured by scanning electron microscopy. It has been established that the highest quality coating is obtained using an electrolyte prepared from nickel hydroxocarbonate.