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Study of temperature and salinity effect on encapsulated surfactants ability to alter wettability and decrease interfacial tension

https://doi.org/10.58224/2619-0575-2024-7-4-87-103
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 87-103 p.
Abstract
In recent decades, the task of increasing the oil recovery factor from productive formations has not lost its relevance. Today, there is a rapidly growing interest in the use of chemical methods to increase oil recovery to enhance production, in particular, using surfactants. To overcome the problem of high adsorption, which prevents the widespread introduction of surfactant flooding in carbonate formations, it is proposed to use the technology of encapsulating surfactants in a solid shell. Thus, the active substance can cover a large part of the reservoir, and therefore more oil can be extracted by injecting surfactants. In this work, the influence of typical reservoir conditions (high temperature and salinity) on the main properties of the dispersions of encapsulated surfactants, namely, a decrease in interfacial tension and a change in wettability, was studied. It is shown that the application of the encapsulation method preserves the necessary properties of surfactants, at which low interfacial tension is observed, and the surface of the carbonate rock becomes more hydrophilic.
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The effect of antioxidants on the survival of yeast cells under the action of X-ray irradiation

https://doi.org/10.58224/2619-0575-2024-7-4-104-117
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 104-117 p.
Abstract
Objectives: Saccharomyces yeast is one of the most studied species for the study of eukaryotic cells. The effect of ionizing radiation on living organisms is studied in radiobiology, the main task of which is to identify the laws of the biological reaction of the body to radiation. This will help to develop methods for monitoring radiation reactions and means of protection against radiation. There are unresolved problems in radiobiology, one of which is radiosensitivity. To study radiation sensitivity, the yeast strain Saccharomyces cerevisiae T-985 was used, as well as rutin, a biologically active substance, a flavonoid with antioxidant and other beneficial properties.
Methods. The spectrophotometric method is based on the use of the free stable radical 2,2-diphenyl-1-picrylhydrosyl (DPPH). After the end of cultivation, aliquots of the yeast suspension were taken from the flasks and transferred into glass flasks with a volume of 1 mL for subsequent irradiation at the Model- KALAN 4 X-ray unit in the IMSEN-IFC of the D.I. Mendeleev Russian Chemical University at an absorbed dose rate of 3 Gy/s according to the Fricke dosimeter [10, 11]. To detect the effects of ionizing radiation and compare the results with the control sample, optical density measurement and microscopy were used.
Results. Rutin may have a protective effect on yeast cells after X-ray irradiation. It has been shown in studies that rutin can reduce oxidative stress and DNA damage caused by irradiation. This may be due to its ability to neu-tralize free radicals and repair damaged molecules. Comparing the results of 0.05mM rutin and rutin and hydrogen peroxide systems, it can be noted that the active form of oxygen negatively affects the survival rate of yeast cells. ionol has a favorable effect on survival and repair processes in yeast cells. The addition of hydrogen peroxide significantly decreases the survival rate of cells immediately after irradiation, but promotes the reparative pro-cesses. As a result of experiments, addition of Rutin with the concentration of 5·10-4 mol/L potentially increases the number of viable cells capable of colony formation than addition of Rutin with the concentration of 5·10-5 mol/L. CFU of S. cerevisiae species with the addition of rutin at different concentrations decreases many times in relation to the control after 3 days at a dose of 400 Gy and 800 Gy of X-ray irradiation.
Conclusions. - With increasing irradiation dose the concentration of rutin decreases, which suggests that it is consumed. The radiation chemical yield of rutin consumption was determined: G (0-400)=0.04 molecules/100 eV; G(400-2000)=0.10 molecules/100 eV.
- The inhibition effect in the reaction with DPPH of rutin solutions without irradiation and one day after irradi-ation was determined. The numerical values are in the range from 67% to 86%, which is more than 50%, which means that rutin has high antiradical properties after irradiation.
- Percentage of dead cells in suspension when rutin was added is less compared to the percentage of dead cells in suspension without rutin at the same absorbed doses.
- In tubes with the addition of rutin of different concentrations, which received a dose of 800 Gy, a day after ir-radiation, there is a significant decrease in the percentage of dead cells compared to the same data obtained with-out the addition of rutin. This can be interpreted as active repair processes.
- At addition of rutin with concentration 5·10-4 mol/l the percentage of dead cells is less than at addition of rutin with concentration 5·10-5 mol/l.
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Removal of harmful gases from the air stream using carbon sorbents based on plant waste of the Republic of the Union of Myanmar

https://doi.org/10.58224/2619-0575-2024-7-4-118-130
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 118-130 p.
Abstract
Objectives: in this work, we evaluated the ability of the adsorbent of gas-vapor activated carbon obtained from the shells of macadamia nuts of one of the enterprises in Myanmar as an agent of the recovery technology using the example of the extraction of n-butanol vapors from their mixtures with air (AVM).
Methods. The object of the study was pre-dried macadamia nuts, which were crushed, heat treated at 650-700°C for 60 minutes in pyrolysis, followed by water vapor at a temperature rise of 15 °C/min without thermal ex-posure, the specific consumption of water vapor was 5 g per 1 g of the resulting activated carbon. The obtained sorbents were analyzed for the sorption properties of C6H6, CCL4 and H2O vapour. Their total volume was deter-mined, their porous structure was estimated by the volume of pores of various sizes, the absorption of iodine and methylene blue from aqueous solutions. Their ability to remove harmful gases during adsorption of n-butanol at different relative pressures was characterized and their adsorption kinetics and isotherms were studied.
Results. It is shown that the values of the coefficients obtained from the kinetic equation a = A(1-e-B·τ) of the obtained active carbons are preliminarily performed in their pores with butanol. According to the values of A and B, these sorbents are actively absorbed by harmful gases from the vapor-air mixture. For comparison, the article presents the quality indicators of active carbons of the CS (coconut shell) and PS (plum seed) brand made frоm a number of agricultural wastes of Myanmar.
Conclusions. The studies allow us to state quite satisfactory absorption properties of the obtained new activated carbon from the shell of macadamia nuts, in the studied process of extracting n-butanol vapors from their mixtures with air, which indicates the probable competitiveness of this adsorbent in solving the problems of purification from vapors of organic substances of emissions of high concentrations, provided that its production is organized in the conditions of Myanmar.
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A set of possible approximative methods for effectively accounting for the contribution of Coulomb integrals to dramatically accelerate the calculations of DFT giant biomolecules: reduction to fast-computable short-range two-center splines plus FMM long-range Coulomb

https://doi.org/10.58224/2619-0575-2024-7-3-49-63
 49-63 p.
Abstract
A set of approximative methods is proposed to radically accelerate the calculation of the contribution of Coulomb integrals in the calculations of DFT giant biomolecules - the limiting stage of such relevant but extremely resource-intensive calculations, including calculations of thousands of docking complexes of thousands of atoms. The proposed complex includes, through a quick and accurate approximation of the contribution of a huge number of 4-center Coulomb integrals through a linear combination of 3-center integrals, and then through a combination of 2-center integrals. The non-multi-complete short-range components of these 2-center integrals are very quickly considered pre-prepared splines from the center-to-center distances. The remaining long-range multipole contributions are quickly calculated for giant molecules in the FMM style (splitting a huge space into regions and subdomains, was originally developed for the dynamics of galaxies). Calculations are saved as much as possible everywhere due to pre-selected combinations of integrals. All two-center components (including the approximation of two-center overlaps of basic functions through linear combinations of single-center auxiliary density functions) are quickly calculated due to splines from internuclear distances from a specially prepared database. For new bases, the database is easily and quickly replenished by decomposing the new basis into a set of universal ex-ponents and a database with them.
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Electrochemical production of manganese dioxide from sulfuric acid electrolyte

https://doi.org/10.58224/2619-0575-2024-7-3-64-77
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 64-77 p.
Abstract
This paper investigates the process of electrochemical production of manganese dioxide from a 10% sulfuric acid electrolyte leaching the active mass of spent manganese-zinc chemical power sources. The relevance of the topic is due to the wide application of MnO2 in modern industry and the need to develop efficient methods for obtaining it from secondary raw materials. The aim of the study was to examine the influence of electrolyte temperature and ultrasonic treatment on the properties and sizes of the obtained manganese dioxide particles. The experimental methodology included electrolysis in a three-electrode cell with temperature variation from 30°C to 90°C and current density of 3-5 A/dm2. Ultrasonic treatment of the electrolyte was carried out at a frequency of 20 kHz. The obtained MnO2 samples were studied using scanning electron microscopy and X-ray energy-dispersive analysis. The results showed that increasing the electrolyte temperature leads to an increase in the size of manganese dioxide particles from 0.2 to 5-10 microns. The introduction of ultrasound allows obtaining highly dispersed MnO2 with crystallite sizes of less than 50 nm. The maximum current yield (92%) is achieved at 60°C and a current density of 5 A/dm2. The practical significance of the work is associated with the possibility of obtaining nanostructured manganese dioxide with improved electrochemical characteristics from spent raw materials. Further research will be aimed at optimizing the parameters of electrolysis and ultrasonic treatment to control the morphology and properties of MnO2.
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Kinetics and mechanism of adsorption of methylene blue dye by crushed sunflower biomass

https://doi.org/10.58224/2619-0575-2024-7-3-78-92
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 78 – 92 p.
Abstract
Objectives: to study the kinetics and mechanism of dye adsorption by cellulose raw materials. Methods. As a sorbent, waste from crop production was used – ground sunflower stalks, initial and modified with 10% NaOH alkali, with a particle size from 1 to 2 mm. Methylene blue dye was selected as an adsorbate by preliminary tests. Adsorption isotherms were constructed to determine the maximum sorption capacity. Kinetic models of sorption of the pseudo-first and pseudo-second order are constructed. In order to determine the mechanism of the process, thermodynamic constants were determined: sorption energy (E), Gibbs energy (ΔG) and Bio coefficient (Bi).
Results. The maximum sorption capacity of the crushed biomass of sunflower stalks in relation to the dye is 0.52 mmol/g for the alkali-modified material, which is 48% higher than the initial content (0.35 mmol/g). Thus, the SP(NaOH) material showed improved sorption properties, and it was selected for further kinetic studies. The sorp-tion energy is 5.82 kJ/mol, which may indicate physical adsorption. The Gibbs energy is -6.3742 kJ/mol, less than zero, which indicates the spontaneity of this process. The adsorption equilibrium for the MG dye occurs after 120 minutes, the kinetic curve has a smooth character. The Bio coefficient is 1.812, therefore, the adsorption process is limited by mixed diffusion.
Conclusions. The analysis of the data obtained made it possible to determine the Bio coefficient reflecting the course of MG adsorption by a mixed–diffusion mechanism over the entire time range of adsorption. This indicates the complex character of the MG adsorption process and confirms the importance of taking into account various factors influencing this process when developing methods for cleaning aquatic environments from organic pollu-tants.
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Investigation of the processing of fossil coals from the Kalewa and Tigyit deposits as raw materials for the production of activated by steam-gas activation

https://doi.org/10.58224/2619-0575-2024-7-3-93-101
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 93-101 p.
Abstract
Objectives: the article reveals the results of research on the technical indicators of the target products of the processes of steam-gas activation of fossil coals of the Tigyit and Kalewa deposits (Tigyit/Kalewa, Myanmar).
Methods. In order to assess the suitability of fossil coals from the Tigyit and Kalewa deposits for the production of granular activated carbons, the results of their petrographic analysis in the form of maceral composition and arbitrary vitrinite reflection indicators are characterized, indicating the potential possibility of their use to solve this problem, based on data from thermographic tests performed in a protective atmosphere, the rational limits of thermal effects on this raw material are estimated during pyrolysis.
Results. The results of steam-gas activation of the named fossil coals are presented, indicating the possibility of obtaining activated carbons with structurally acceptable adsorption properties for practical use, it is concluded that it is necessary to improve the processes of the named steam activation in order to optimize them.
Conclusions. Thus, the described results indicate the fundamental possibility of obtaining on the basis of fossil coals of the Kalewa and Tigyit deposits by the characterized reception of sufficiently high quality activated car-bons.
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Extraction of sodium hydroxide from cotton processing facilities

https://doi.org/10.58224/2619-0575-2024-7-3-102-108
 102-108 p.
Abstract
The process of extracting technological contaminants from textile materials is considered as a mass transfer process, for the intensification of which pulsed exposure to an ultrasonic field is chosen.
A lightweight fabric was selected for the study in order to eliminate the influence of surface density and fabric thickness on the kinetics of the process. The results of an experimental study of the kinetics of the extraction of so-dium hydroxide during washing after mercerization of a light standard cotton fabric are presented. The studies were carried out in laboratory conditions on a model installation with a different washing bath module without intensification and with the use of ultrasonic exposure as an intensifier. At the same time, the optimal distance from the ultrasound source to the washed tissue was determined based on previous studies. Exposure to ultrasound sig-nificantly reduces the duration of the process, especially at the initial stage. Equations for approximating the kinet-ics curves of sodium hydroxide extraction from cotton fabric without intensification and with intensification by ul-trasonic action are obtained, and their parameters are determined. The correlation of calculated and experimental data is acceptable for approximate kinetic calculations. The obtained equations can be practically used in engi-neering practice for a preliminary assessment of the duration of the process of extrusion-washing of cotton fabrics belonging to the group of light cotton fabrics from alkali in various modules of the washing bath.
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Improving the energy efficiency of the drying process of fibre materials

https://doi.org/10.58224/2619-0575-2024-7-3-109-119
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 109-119 p.
Abstract
In the modern textile industry, one of the most energy-consuming and widespread processes is drying, to which fibers, yarns and fabrics are subjected after various operations (impregnation, extraction, dyeing, etc.). A complex heat and mass transfer drying process is carried out at sufficiently high temperatures and is energy-consuming. To reduce the overall energy consumption in textile production, it is necessary to carry out preliminary dehydration of materials before drying, for example, in centrifuges, intensification of drying by physical fields, etc. Modern industrial drying plants for textile materials provide sufficiently fast and uniform drying, increasing the overall efficiency of this stage of production of finished textile products. Energy-efficient solutions for the drying process can reduce the negative impact of the process on the environment. Industrial drying of textile materials is carried out in convective or contact dryers using thermal energy. In convective dryers, the drying agent is air. In contact dryers, water vapor is used to heat the drums. The article discusses important areas of improvement of the technological process and equipment designed for drying fibrous materials. These include: the introduction of me-chanical pre-drying dewatering; the choice of hybrid systems in drum dryers; utilization of condensate and steam in drum dryers; insulation of end panels and the abolition of intermediate drying in drum cylindrical dryers; con-trol of moisture content of the material to prevent drying of the fabric; reduction of dryer downtime by planning the supply of batches of fabric; the use of multiple drying of fabric in drum dryers. The improvement of the drying pro-cess of textile materials is possible with the use of an ultrasonic field, infrared radiation and other intensification methods while ensuring timely maintenance of drying equipment, programmable temperature changes during the drying process.
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Improving the impact resistance of a polymer composite material based on epoxy prepreg through the addition of nonwoven material based on polyamide 12

https://doi.org/10.58224/2619-0575-2024-7-3-120-136
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 120-136 p.
Abstract
The effect of introducing nonwoven material based on polyamide PA 12-E on the mechanical properties of polymer composite materials based on the epoxy autoclave prepreg T107 was investigated. The presence of the nonwoven material slightly lowers the glass transition temperature to 171 ℃, which does not affect the feasibility of using the material up to the maximum operating temperature of 120 ℃. Electron microscopy studies of the composite's cross-sections revealed uniform distribution of the thermoplastic phase between the layers of carbon fabric as well as high adhesion of polyamide to the epoxy matrix. It was demonstrated that introducing nonwoven material does not lead to a reduction in the mechanical properties of the composites. The main advantage of composites based on nonwoven material is their enhanced resistance to impact loads. Under a free impact with energy of 6.67 J per 1 mm of the specimen, a through penetration with fiber destruction was observed in the sample without the nonwoven material, while for the sample with nonwoven material, the damage was characterized by delamination without fiber damage. The compressive strength after impact increased from 257 to 326 MPa with the introduction of nonwoven material. As a result, the proposed modification of commercial prepreg could expand the range of applications for the material and improve safety, particularly in aircraft structures.
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