English English

Vol. 9 Issue 3

Archives Journal Chemical Bulletin Vol. 9 Issue 3

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
, , ,
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.
PDF

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
, , ,
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.
PDF

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
, , ,
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.
PDF

Adsorption of petroleum products with sunflower seed husk carbonate

https://doi.org/10.58224/2619-0575-2026-9-3-4
, , ,
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.
PDF

Development of technological solutions for neutralization of acidic wastewater

https://doi.org/10.58224/2619-0575-2026-9-3-5
,
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.
PDF