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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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Influence of lignin and its activated forms on the physico-mechanical and rheological properties of bitumen

https://doi.org/10.58224/2619-0575-2026-9-3-1
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Abstract
The relevance of the work is due to the need to replace expensive polymer modifiers and involve large-scale waste from the pulp and paper industry in the production of road construction materials. The purpose of the study is a comprehensive assessment of the effect of various types of lignin and activation methods on the physico-mechanical and rheological properties of bitumen. Bitumen of the BND 100/130 brand was used in the work. Samples with the addition of pure lignin (0.3–0.7%), activated lignin, lignosulfonate, as well as complex formulations with the plasticizer ENMA and SBS polymer were studied. It has been shown that the introduction of pure lignin increases the softening temperature and aging resistance, but worsens the low-temperature properties and leads to heterogeneity of the system at concentrations above 0.7%. The activation of lignin increases its reactivity, allowing the introduction of a modifier without loss of uniformity. It has been established that the combined use of activated lignin with SBS and plasticizer provides an extension of the temperature range of working capacity. Rheological tests in accordance with GOST R 58400.1-2019 confirmed the increase of the PG grade from PG 58-28 (initial bitumen) to PG 70-34. The best set of properties is achieved by partially replacing SBS with activated lignin, which confirms the prospects of using lignin as an effective and environmentally friendly component of polymer-bitumen binders.
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Теоретический анализ и экспериментальное изучение тройной системы CsCl−Cs2MoO4−WO3

Theoretical Analysis and Experimental Study of the CsCl−Cs2MoO4−WO3 Ternary System
https://doi.org/10.58224/2619-0575-2026-9-3-2
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Abstract
The objective of physicochemical analysis is to establish the dependence of the properties of an equilibrium system on its parameters. State parameters are typically understood to include composition, pressure, and temperature. These dependencies are expressed in various diagrams, including state-property parameters. In practice, the composition-property diagram is of great importance. Analysis of such a diagram provides information on the nature of component interactions, while the pressure and concentration of components provide information on the composition and stability of the chemical compounds formed in the system. The set of dependencies of all the properties of a uniform system as a function of parameters allows one to graphically depict a phase diagram and a state diagram. To examine each state diagram of a system, the concepts of phase, system, degree of freedom, component, constituent substance, and thermodynamic equilibrium are used.
Many issues related to the electrochemical synthesis of inorganic oxide bronzes are examined and resolved experimentally and in practice.
Based on experimental data for materials with regulated properties, the ISSs are studied. Based on the results of experimental studies, the first promising regions of the phase diagram for the synthesis of molybdenum-vanadium cesium bronzes have been obtained.
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Multifactorial modeling of the distribution of heavy metals in the “water – bottom sediments” system (using the example of the Kuibyshev reservoir)

https://doi.org/10.58224/2619-0575-2026-9-3-3
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Abstract
This paper presents the results of long-term monitoring (2019–2026) of Zn, Ni, Fe, Cu, Cr concentrations in surface waters and bottom sediments of the Kuibyshev Reservoir near Ulyansk city. The average concentrations of Zn, Ni, Fe, Cr exceed the maximum permissible concentrations for fishery water bodies by factors of 1.6–4.4. Hierarchical clustering and K means methods identified three groups of metals: seasonally dependent (Fe, Ni, Zn), conservative (Cu), and metals with signs of a point anthropogenic source (Cr). The interphase distribution coefficients lgKd were calculated: 3.35–3.39 for Cu and Zn, 2.80 for Ni, and 2.22 for Fe, indicating different accumulation capacities in bottom sediments. Using multiple linear regression, empirical relationships between metal concentrations and water temperature and pH were obtained. A forecast for the spring period of 2027 predicts exceedances of MPC: Fe – 7.9 times, Zn – 2.3, Ni – 1.6, Cr – 1.7 times. Copper remains the only metal with concentrations below the standard. The obtained results can be used to improve environmental monitoring systems and predict water quality in large lowland reservoirs.
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Adsorption of petroleum products with sunflower seed husk carbonate

https://doi.org/10.58224/2619-0575-2026-9-3-4
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Abstract
Оbjectives: the paper addresses the problem of environmental pollution by oil and petroleum products and substantiates the possibility of using sunflower seed husk carbonizate as an effective and economically affordable adsorbent for the fine purification of natural waters from oil contamination.
Methods. The physicochemical processes of sunflower seed husk pyrolysis in oxidative‑air and oxygen‑free (argon) atmospheres were investigated by thermal analysis (thermogravimetry and differential scanning calorimetry). Adsorption tests were carried out in accordance with GOST No. 33627-2015 using crude oil from the Yamal field and TS‑1 aviation kerosene. The selectivity of the adsorbent was evaluated in a model "oil‑water" system, and desorption characteristics were studied by gravimetry at room temperature.
Results. The main stages of thermo‑oxidative degradation and pyrolysis of sunflower seed husks were established: dehydration (up to 248-254 °C), release of volatile organic compounds (248-361 °C), and carbonization (361-820 °C); the yield of solid carbon residue in an inert atmosphere (13.2%) is 2.5 times higher than in air. The absorption capacity of the carbonizate was shown to reach 1.84 g/g for crude oil and 1.11 g/g for kerosene, which is comparable to known adsorbents from plant‑derived raw materials. The selectivity of the adsorbent in an aqueous medium was confirmed. A two‑stage nature of kerosene desorption was established: rapid loss of 9.3% within the first 1.5 hours, followed by slow desorption up to 48 hours.
Conclusions. It was found that sunflower seed husk carbonizate exhibits high thermal stability, competitive oil capacity, and selectivity towards petroleum products. The exclusion of the energy‑intensive activation stage significantly reduces the adsorbent production cost. The obtained results indicate the promise of using pyrolysis products of sunflower seed husks for developing effective means of oil spill remediation.
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Development of technological solutions for neutralization of acidic wastewater

https://doi.org/10.58224/2619-0575-2026-9-3-5
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Abstract
The article considers the problem of neutralization of acidic wastewater generated during the regeneration of cation exchange filters at the Novo-Salavatskaya CHPP. The initial wastewater has a pH of 1.3 and a sulfate content of 11.6 g/dm³. The aim of the work is to develop a technological scheme and neutralization modes that allow obtaining two by-products: alabaster and manganese concentrate. The methods used include potentiometric pH determination, complexometric titration for calcium, and turbidimetry for sulfates. The experiment included two stages: precipitation of calcium sulfate with a 10% CaCl₂ solution and subsequent neutralization of the filtrate in a column packed with carbonate manganese ore. It was found that the optimal solution feed rate through the column is 4.57 cm³/min, at which the pH rises to 6.75 and the sulfate content decreases to 2.15 g/dm³. The CaSO₄ precipitate after calcination at 170–180 °C is converted into alabaster with a yield of 4.6 g per 1 dm³ of wastewater. The insoluble residue of the ore is enriched in MnO₂ up to 34–36% and can be used as a manganese concentrate. It is concluded that the proposed two-stage scheme makes it possible to abandon expensive alkaline reagents and obtain two marketable products.
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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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Process window for twin-screw compounding of PETG with short carbon fibre for FFF filament

https://doi.org/10.58224/2619-0575-2026-9-2-5
Abstract
Оbjectives: to establish a process window for pilot-scale twin-screw compounding of polyethylene terephthalate glycol (PETG) with short carbon fibre for subsequent FFF filament production and to identify the parameters that are critical to material reproducibility.
Methods. Two formulations containing 5 and 10 wt% carbon fibre and 2 wt% maleic-anhydride-functionalised low-density polyethylene were analysed. PETG was dried at 65 °C for 3 h, milled to 50–150 μm and sieved. Compounding was performed in a 30 mm twin-screw extruder with L/D = 44 at 220 rpm, a melt pressure of 1.0 MPa and a drive load of 70%. Descriptive analysis included screw length, peripheral speed, component mass ratios and the 11-zone thermal profile.
Results. The thermal sequence comprised heating from 200 to 240 °C with a 240 °C plateau, controlled cooling to 210 °C, and terminal stabilisation at 230 °C. The active screw length was 1.32 m and the peripheral speed was 0.346 m/s. For 5 and 10 wt% fibre, PETG-to-fibre ratios were 18.6 and 8.8, while compatibiliser-to-fibre ratios were 0.40 and 0.20. A critical-parameter map covering initial polymer drying through final pellet drying was developed. Pilot-batch filament was processable on an open-frame FFF printer; the screening flexural modulus was 3.5–4.0 GPa.
Conclusions. Reproducible carbon-filled PETG requires coordinated control of moisture, feeding, thermomechanical history and strand drawing. The 3.5–4.0 GPa value is flexural modulus, not flexural strength. Separating fibre-content and supplier effects requires factorial experiments, rheology, microscopy and standardised mechanical testing.
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