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2026

Archives Journal Chemical Bulletin Vol. 9

A study of the effect of ionizing radiation on the physicochemical properties of solid waste from oil pipeline transportation

https://doi.org/10.58224/2619-0575-2026-9-2-1
Abstract
The aim of the study was to experimentally investigate the effect of gamma irradiation in the absorbed dose range of 25-200 kGy on the physicochemical properties of solid waste from oil pipeline transportation. The object of the study was asphaltene-resin-paraffin deposits collected during the cleaning of a main oil pipeline. The following tasks were solved during the work: quantitative determination of changes in the group hydrocarbon composition (oils, paraffins, resins, asphaltenes) by adsorption chromatography; analysis of molecular weight distribution by gel permeation chromatography; assessment of rheological characteristics (melting point, pour point, relative viscosity) and thermal stability by thermogravimetric analysis. It was found that at a dose of 200 kGy, the paraffin content decreases by 1.65 times, while the asphaltene content increases by 1.8 times. The system's polydispersity increases from 6.56 to 10.72, the relative viscosity at 80°C more than doubles, and the coke residue increases from 3.5% to 8.2% by weight. The practical significance of these results lies in substantiating the possibility of using radiation-modified waste as a component of bitumen compositions with increased heat resistance or as a raw material for producing carbon materials. The data obtained can be used in the development of technologies for the disposal of oil waste using ionizing radiation.
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Surface modification of silica and titanium dioxide powders with silver nano- and microparticles by a thermal method

https://doi.org/10.58224/2619-0575-2026-9-2-2
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Abstract
Objectives: to modify silica powder synthesized by the sol–gel method and commercial titanium dioxide with silver particles via thermal decomposition of silver nitrate within oxide matrices. To carry out a comparative study of the morphology and distribution of silver on different supports in terms of their potential application in photocatalysis and as functional abrasive fillers in toothpastes. To determine the nanostructure and specific surface area of silica and to assess the influence of the porous structure of the support on the dispersion of the silver phase.
Methods. Silica was obtained by sol–gel synthesis based on tetraethoxysilane. Modification of titanium dioxide and silica with silver was performed by impregnation with a silver nitrate solution followed by thermal decomposition of the salt at 700 °C. The morphology and distribution of silver were investigated by scanning electron microscopy and energy-dispersive elemental analysis with mapping. The nanostructure and porosity of silica were characterized by Sears titration and methylene blue adsorption with calculation of Langmuir equation constants and specific surface area.
Results. It was shown that commercial titanium dioxide consists of coarse particles (medium size 35,4 µm), whereas the sol–gel synthesized silica has the form of microspheres with medium size 1,4 µm and is composed of primary nanoparticles of about ~3.7 nm. According to methylene blue adsorption data, the specific surface area of silica is about 10 m²/g, which corresponds to a mesoporous structure. It was found that, upon modification of titanium dioxide with silver, submicron and micron-sized silver particles (up to ~2 µm) are formed on its surface, whereas on mesoporous silica a more highly dispersed silver phase is produced, which is not size-resolvable in SEM mode but is uniformly distributed over the surface according to EDS mapping data.
Conclusions. The morphology of the silver phase strongly depends on the type and structure of the oxide support. Mesoporous nanostructured silica promotes the formation of more highly dispersed (nanosized) and uniformly distributed silver particles compared to commercial titanium dioxide, on the surface of which submicron and micron silver inclusions prevail. The obtained data can be used to optimize the photocatalytic and antibacterial properties of silver-containing composites, as well as to select the composition of abrasive fillers based on SiO₂@Ag and TiO₂@Ag for toothpastes and other oral hygiene products.
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Analysis of classification and composition of modern lithifying additives

https://doi.org/10.58224/2619-0575-2026-9-2-3
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Abstract
The article presents an analysis of the classification and composition of modern lithifying additives used for the treatment of liquid salt concentrates from reverse osmosis units. Natural and synthetic sorbents are considered, their characteristics including specific surface area, porosity, elemental composition and thermal stability. The results of studies of the individual efficiency of additives and their combinations are presented, and optimal compositions for obtaining solid waste of hazard classes IV-V are determined.
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Using the Gibbs excess energy diagrams of four-component systems to select extractive agents

https://doi.org/10.58224/2619-0575-2026-9-2-4
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Abstract
Objectives: сomparison of extractive agents for the separation of ternary azeotropic mixtures using the Gibbs excess energy diagrams on the example of methanol – tetrahydrofuran – acetonitrile mixtures; prediction of extractive distillation results.
Methods. Computational experiment for calculating phase equilibria and the distillation process using the Non Random Two Liquid (NRTL) model; construction and visualization of data arrays for excess Gibbs energy for four-component systems using the marching cubes algorithm, implemented in the Python programming language have been developed.
Results. A computational experiment was conducted on simulation of vapor–liquid equilibria in four–component derivative systems, including a separable substances methanol, tetrahydrofuran, acetonitrile and an extractive agent. The Gibbs excess energy diagrams of derivative systems are constructed, the selective properties of extractive agents are analyzed, and the results of extractive distillation of methanol – tetrahydrofuran – acetonitrile mixtures with dimethyl sulfoxide, valeronitrile, and glycerin are predicted. The forecast is confirmed by calculations of extractive distillation for different compositions of methanol – tetrahydrofuran – acetonitrile mixtures with agents under discussion. The extractive distillation flowsheet with dimethyl sulfoxide is energy efficient at separating ternary mixtures of different compositions.
Conclusions. Using the marching cubes algorithm, it is possible to visualize the composition-excess Gibbs energy data array for four-component systems. The possibility of evaluating the selective action of agents and predicting the product flows of an extractive distillation column for the methanol – tetrahydrofuran – acetonitrile mixtures has been demonstrated, which plays a crucial role in the development of principal separation flowsheets.
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Comparison of the effectiveness of rice husk ash for solid phase synthesis of wollastonite and diopside

https://doi.org/10.58224/2619-0575-2026-9-1-1
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Abstract
Objectives: This study aims to evaluate the prospects of using rice husk ash for the production of calcium-magnesium silicates and to identify differences in the solid-phase synthesis processes of wollastonite and diopside based on rice husk ash.
Methods. X-ray quantitative phase analysis was used to analyse the obtained samples of synthetic wollastonite and diopside. The porosity of calcium-magnesium silicates was evaluated by a static volumetric method using low-temperature nitrogen adsorption. The elemental composition of the samples was determined using an Oxford INCA X-max 80 energy dispersive detector, and electron microscopic analysis was performed using a Jeol JSM7001F scanning microscope.
Results. Experimental data comparing the properties of synthesized diopside and wollastonite showed that wollastonite is characterized by high porosity and average particle size compared to diopside due to the lower temperature of solid-phase synthesis. The structure of synthetic wollastonite is distinguished by the presence of large irregularly shaped inclusions with a small amount of needle-like particles, while synthesized diopside does not contain needle-like particles, and the inclusions are characterized by smaller size and uniform distribution throughout the volume.
Conclusions. When obtaining calcium-magnesium silicates by solid-phase synthesis based on rice husk ash, the yield of the final product synthetic diopside is significantly higher than that of synthetic wollastonite. The process of synthesizing diopside is less labor-intensive and time-consuming, but more energy-intensive due to the higher synthesis temperature of diopside.
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Influence of technological parameters of potassium chloride production on corrosion-abrasive wear of double-layer steel 1.4462

https://doi.org/10.58224/2619-0575-2026-9-1-2
Abstract
The paper presents the results of laboratory studies of corrosion-abrasive wear of a screw dissolver made of duplex steel 1.4462 in an environment simulating potassium chloride production conditions (4RU of JSC "Belaruskali"). The influence of mechanical impurities (abrasive), temperature (105 °C), pH (4-8), artificial air supply, and incomplete immersion mode was experimentally studied. It has been established that the presence of abrasive increases the mass loss rate by 10 times (up to 0,015 g/day) compared to purely chemical corrosion [2]. The most intense pitting damage is observed in areas with oxygen access. An alkaline environment (pH= 8) promotes the formation of protective deposits, while an acidic one (pH= 4–7) intensifies corrosion [7]. Equipment operation with incomplete immersion of the agitator increases the corrosion rate by 40 % [2, 9]. Duplex steel 1.4462 shows high resistance to chemical corrosion, but its service life is sharply reduced under the combined influence of abrasive and non-standard operating conditions [2, 20]. Practical recommendations for extending equipment service life are given.
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Mathematical modeling of a solid oxide fuel cell

https://doi.org/10.58224/2619-0575-2026-9-1-3
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Abstract
Objectives: development of a mathematical model to describe the phenomena occurring in a medium-temperature solid oxide fuel cell. Solving the model equations requires finding a number of kinetic parameters, including the rate constants of electrochemical reactions.
Methods. To determine the viscosity of polymer solutions, their molecular weight and to study the adsorption of k-carrageenan on CX, the method of capillary viscometry was used. The assessment of the stability of the zones over time was carried out photometrically.
Results. The mathematical model is based on a system of partial differential equations and includes material and heat balance equations, as well as charge balance relationships. An algorithm for numerically solving the mathematical model equations and a corresponding software module for calculating the equations implemented in the Python programming language have been developed.
Conclusions. The developed mathematical model adequately describes the processes occurring at the electrodes of a medium-temperature fuel cell. The optimal fuel-to-oxidizer ratio was determined to be 1:10.
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Phase formation in triple salt systems Rb2MoO4–AMoO4–R(MoO4)2 (A = Mg, Ca, Mn, Co, Ni, Zn, Sr, Cd, Ba, Pb; R = Zr, Hf) and some properties of triple molybdates Rb5A0.5R1.5(MoO4)6

https://doi.org/10.58224/2619-0575-2026-9-1-4
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Abstract
As a result of studying the possibility of phase formation in triple salt systems Rb2MoO4–AMoO4–R(MoO4)2 (A – divalent elements; R = Zr, Hf) phases of the composition Rb5A0.5R1.5(MoO4)6, were obtained, which are assigned to a large family of ternary molybdates with the general formula M5A0.5R1.5(MoO4)6 (M – single valent element, A – divalent element, R = Zr, Hf) and represent a series of isostructural substances crystallizing in trigonal syngony (sp.gr. R3c или R3) [1, 2]. Crystallographic and thermal characteristics of the synthesized compounds were determined.
Methods. The subsolidus structure of the ternary salt systems Rb2MoО4–АMoO4–R(MoO4)2 was established using the “intersecting cuts” method. polycrystalline samples The powder samples compounds Rb5А0.5R1.5(MoO4)6 (A = Mg, Ca, Mn, Co, Ni, Zn, Sr, Cd, Ba, Pb; R = Zr, Hf) were obtained by solid-phase synthesis at 500–530°C.
Results. The subsolidus structure of the ternary salt systems Rb2MoO4–AMoO4–Zr(MoO4)2 (A = Mn, Pb,), Rb2MoO4–AMoO4–R(MoO4)2 (A = Zn, Cd, R = Zr, Hf) was established. The Rb5A0.5R1.5(MoO4)6 (А = Mg, Ca, Mn, Co, Ni, Zn, Sr, Cd, Ba, Pb; R = Zr, Hf) were obtained in powder form, their crystallographic and thermal characteristics were determined. IR and Raman spectra were recorded and analyzed for the compounds Rb5A0.5Zr1.5(MoO4)6 (A = Ni, Со, Mg, Zn), Rb5Ba0.5Zr1.5(MoO4)6.
Conclusions. Phase formation in ternary salt systems Rb2MoO4–AMoO4–R(MoO4)2 (A = Mg, Mn, Zn, Ni, Co, Cd, Ca, Pb, Sr, Ba; R = Zr, Hf) was studied and a subsolidus structure was established for six of them. Compounds Rb5A0.5R1.5(MoO4)6 were obtained by solid-phase synthesis at 500–530°C and belong to a large family of ternary molybdates with the general formula M5A0.5R1.5(MoO4)6 (M – single valent element, A – divalent element, R = Zr, Hf) and crystallize in two structural types: molybdates with large divalent metals (A = Ca, Sr, Ba, Pb) – in the structural type Tl5Pb0.5Hf1.5(MoO4)6 (пр.гр. R3, [2]), molybdates with divalent metals whose radius is less than 1Ǻ (A = Mg, Mn, Zn, Ni, Co, Cd) – in the structural type K5Mg0.5Zr1.5(MoO4)6 (пр.гр. R3c, [1]).
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