Sorption Properties and Adsorption Kinetics of Cd²⁺ Ions on Silica Derived from Rice Husk
This study provides a comparative analysis of the adsorption efficiency and structural characteristics of silica (SiO₂) sorbents derived from rice husk for the removal of Cd²⁺ ions. Two types of sorbents were examined: the thermally synthesized SiO₂ (650) sample and the purified SiO₂ clean (650) sample obtained through an alkaliprecipitation method. According to the results of elemental analysis, the sample obtained by the thermal method contained 85.7% SiO₂, and when purified by the alkaline precipitation method, it contained 100% SiO₂. Experimental findings revealed that the sorption capacity of SiO₂ (650) was 7.38 mg/g, while that of SiO₂ clean (650) reached 7.46 mg/g. Both sorbents achieved equilibrium within 10-30 min, with removal efficiencies of 96.7% and 97.7%, respectively. Kinetic analysis demonstrated that the adsorption behavior of Cd²⁺ ions follows the pseudo-secondorder model (R² > 0,999), indicating a predominant chemisorption mechanism. The enhanced performance of the SiO₂ clean (650) sorbent is attributed to its higher number of active surface sites. Overall, silica sorbents synthesized from rice husk represent environmentally safe, accessible, and economically efficient materials for the purification of heavy-metal-contaminated water. The outcomes of this research provide a foundation for further improvement of rice-husk-derived sorbents, enhancement of their adsorption capacity, and potential expansion into industrialscale applications.
Copyright (c) 2025 https://creativecommons.org/licenses/by/4.0
Research on the Technology for Manufacturing Carbon Composite Casings for Small Solid-Propellant Rocket Motors
The article is dedicated to the study of the manufacturing technology of carbon fiber-reinforced plastic (CFRP) casings for small-sized solid-propellant rocket motors. The primary focus is on selecting the optimal epoxy binder and technological parameters that ensure high mechanical performance of the composite material. Three epoxy systems were evaluated: "Epikote LR 285 + Epikure LH287", "Kumho KER-828 + ZT 143", and "ED-20 + Etal Inject". Optimal resin/hardener ratios were determined based on mechanical testing of samples in tension and bending. The best strength results ─ both for the pure binder (94 MPa) and the reinforced composite (1230 MPa in tension) ─ were achieved with the ED-20/Etal Inject B system at a 100/20 ratio. A manufacturing process was developed using filament winding of carbon roving impregnated with epoxy resin. The winding was performed with alternating fiber layup angles (0°, 45°, 90°) to ensure isotropic mechanical properties. The influence of winding angle and the mass fraction of carbon fiber in the composite (ranging from 50% to 70%) on strength was studied. The optimal result was obtained at 70% fiber content: 660 MPa in axial tension and 645 MPa in hoop tension. Carbon fiber-reinforced plastic casings with a wall thickness of 3 mm were manufactured and tested. Hydrostatic and hot-fire tests were conducted. At the motor's operating pressure of 33 bar, the casing demonstrated stable performance without failure. The results confirm the high strength and airtightness of the CFRP design, making this technology promising for use in small-scale rocket systems.
Fire Testing of Rocket Engine Nozzle Materials
This article presents the results of research on materials used in the nozzle section of a rocket engine. The study analyzed the properties of high-strength metal alloys, heat-resistant, and thermal insulation materials. A review of materials proposed for use in nozzle constructions was conducted. Three different materials were selected for experimental studies: structural steel 30KhGSA, textolite (grade A), and pressed graphite. To assess the thermal and erosion resistance of these materials, fire tests were conducted on a 70 mm caliber engine test stand. As a result of the tests, the level of erosion wear was determined in different nozzle zones: the converging section, the throat, and the diverging section. Changes in the geometric dimensions (diameter and angles) of nozzle components were monitored. The graphite material demonstrated the highest thermal and erosion resistance in the throat region. While steel materials are effective in terms of mechanical strength, and textolite is suitable as a thermal insulator, it was found to be significantly worn under high temperatures. Overall, the results of the conducted research can serve as a scientific and practical basis for designing and selecting materials for rocket engine nozzle blocks. The work provides recommendations for the proper selection of materials for small- and medium-caliber solid-fuel rocket engines.
Synergistic Effects of Li+─Zn2+ Hybrid Electrolytes on Corrosion Suppression and Electrochemical Performance of ZnǁLiFePO4 Aqueous Batteries
Aqueous zinc-ion batteries (AZIBs) are promising for safe and sustainable energy storage. However, zinc anode instability, dendrite formation, hydrogen evolution, and corrosion limit long-term performance. This study investigates hybrid electrolytes with varying Zn2+ and Li+ ratios. The 1 M ZnSO4 + 1 M Li2SO4 electrolyte demonstrated the lowest corrosion current density (0.00026 mA·cm-2), reduced charge transfer resistance (Rct = 8.91 Ω), and stable cycling performance (135-158 mAh·g-1 over 50 cycles). Electrochemical and morphological analyses confirmed uniform, dendrite-free Zn deposition. These results highlight the synergistic effect of Li+–Zn2+ hybrid electrolytes in enhancing the performance of AZIB.
Flocculation Treatment of Water Using Industrial Flocculants
Water purification is one of the most pressing issues of modern times. In this regard, the possibility of flocculation treatment of kaolin suspension with a high content of heavy metal ions was investigated using industrial flocculants: “Kemira Superfloc A-120”, “Rusfloc 506”, and the coagulant “Kemira Ferix-3”. It was shown that the highest degree of suspension clarification is achieved at a flocculant concentration of 0.16 g/L. Increasing the concentration to 0.24 g/L leads to system stabilization due to the recharging of the clay particle surfaces. The electrokinetic potential of kaolin particles is -21.8 mV, which shifts to -30.4 mV when treated with the anionic flocculant “Superfloc A-120”. In the presence of the cationic flocculant “Rusfloc 506” and the coagulant “Kemira Ferix-3”, charge inversion occurs, and the ζ-potential increases to +6.5 mV and +5.5 mV, respectively. Flocculation treatment of the kaolin suspension is accompanied by a decrease in the concentration of metal ions.
Adsorption Studies of Chemically Activated Carbons Based on Lignocellulosic Raw Materials for the Elimination of Proinflammatory Cytokines
In this study, the adsorption properties of carbon materials synthesized from rice husks for the elimination capacity of proinflammatory cytokines: tumor necrosis factor-α (TNF-α), interleukins IL-6, and IL-8 was invesitgated. The sorbents were obtained by chemically activating rice husks impregnated with phosphoric acid in a 2:1 ratio for 1 hours at 400-500°C. The textural characteristics of the samples were examined using low-temperature nitrogen adsorption-desorption, mercury porosimetry, and scanning electron microscopy. The studied samples of carbon from carbonized rice husk (KRSh-R-400A/V, KRSh-R-500A/V) showed high adsorption results of inflammatory cytokines compared to commercial mesoporous spherical carbon TE7.
Development of Technology for Purifying Ion Exchangers from Silicon Impurities During the Processing of Productive Uranium-Containing Solutions
The purpose of this work is to investigate the possibility of removing silicon from ion exchangers used in the production cycle, to determine the optimal concentration of alkaline solutions for desilication, and to subsequently analyze the degradation of ion exchangers (resins) employed in sulfuric-acid uranium extraction schemes. The relevance of this study arises from the fact that in Kazakhstan, the process of selective sorption of uranium ions by ion-exchange resins is widely used as the primary method of uranium extraction. During sulphuric acid leaching of uranium ores, silicic acid enters the solution, which has a negative effect on the processes. The transfer of silicic acid into the solution and its participation in the sorption process lead to the gradual accumulation of silicon in anion exchangers, where its maximum content reaches 12-17%. The data was obtained as a result of monitoring ion exchange resins from the technological process. Since silicon is not washed out of the resin during further processing of the anion exchanger, its accumulation leads to a decrease in the resin's uranium capacity and a loss of mechanical strength. The frequency of regeneration of ion exchangers (ion exchange resins) in industrial conditions depends on several factors: the type of ion exchanger, the composition of the initial solution, the operating mode, and the quality requirements for the product obtained. In this regard, the problem of an effective method for reducing the negative impact of silicon in the processing of productive solutions appears to be important and necessary for study.
Production of Carbon Black by Pyrolytic Processing of Carbon-Containing Wastes
This study aims to investigate the possibility of obtaining carbon black with low ash content and a high specific surface area by pyrolytic processing of carbon-containing wastes, particularly petroleum residues and spent lubricating oils. The operating parameters of the pyrolysis process and the characteristics of the resulting carbon black were examined. The morphological, elemental, and structural properties of the obtained solid products (carbon black) were analyzed using modern physicochemical methods. Elemental analysis showed that the carbon black sample (TK-1) derived from spent lubricating oils contains predominantly carbon (78%), whereas the sample (TK-2) obtained from petroleum waste exhibits an increased content of inorganic elements (Si, Al, Fe, etc.). SEM micrographs revealed that TK-1 has a loose, highly porous structure, while TK-2 is characterized by a mineralized, coarse-grained morphology. X-ray diffraction (XRD) analysis confirmed that both samples possess an amorphous graphite-like structure. The specific surface area determined by the BET method was 150 m²/g for TK-1 and 90 m²/g for TK-2. The results demonstrate that the TK-1 material obtained from spent lubricating oils, due to its high carbon content and well-developed surface, is a promising material for use as an adsorbent, catalyst, and a component in composite materials. It was found that the TK-2 sample derived from petroleum waste requires additional modification and purification stages due to the high amount of inorganic impurities.Keywords: carbon black, fuels and lubricants, pyrolysis, recycling, carbon-containing wastes.
Dry Reforming of Ethanol Based on Copper Catalyst
In this article, the catalytic activity of copper oxide supported on 5A, HZSM-5, Al2O3, SiO2 carriers in the reaction of dry reforming of ethanol was investigated. The results of the study showed that the formation of Н2, СО, С2Н4 and СН4 gases in the reaction products depends on the reaction temperature and the catalytic activity of the catalyst. The 3%CuO/Al2O3 catalyst showed activity for obtaining synthesis gas at T = 800 °C, and the 5%CuO/SiO2 catalyst showed activity for obtaining ethylene at T = 550 °C. 20.6 vol.% H2 and 37.5 vol.% CO are formed on the 3%CuO/Al2O3 catalyst. In order to increase the ethylene concentration, the effect of copper concentration supported on the SiO2 carrier in the DRE process was studied. According to the obtained data, on the 5%CuO/SiO2 catalyst the ethylene concentration increased to 35 vol.%. The catalytic activity is confirmed by peaks in the TPR profile, according to which the reduction of CuO to Cu⁰ in the 5%CuO/SiO2 catalyst occurs more easily and at lower temperatures compared to other catalysts. The reduction of oxides to metals at low temperatures on the catalyst surface allows increasing the catalytic activity of the catalyst.
Recycling Plastic Waste in An Environmentally Friendly Way – Using it in Road Construction
Full compliance with the technology of laying road surfaces does not always show high reliability. Low durability of roads is determined by insufficient quality indicators of the bitumen used. Therefore, the transition to the use of polymer-bitumen binders is a trend in the development of the road industry, which have higher quality characteristics. Most often, thermoplastic elastomers of the styrene-butadiene-styrene type are used to modify bitumen, which are characterized by a relatively high cost. This work experimentally demonstrates the effect of the combined use of plastic waste and ready-made polymer modifiers on the rheological properties and chemical bond of bitumen binders to reduce the cost of polymer-bitumen binders. In the work, secondary polyethylenes of different densities (LDPE and HDPE) were used in an amount of 1 to 2% together with ready-made polymer modifiers (SBS and Elvaloy). The physical-mechanical properties of the obtained bitumen binders were determined by standard methods according to ST RK. The results of the study show that with the increase of plastic waste, the plasticity range of bitumen in the presence of modifiers increases. This indicates that the finished polymers have a significant effect on improving the physical and mechanical properties of modified bitumen. New results were obtained on the effect of plastic waste on the quality of polymer-bitumen binder. According to the results of the work, it was found that the selected plastic waste is compatible with the ready-made polymer modifiers.
High Temperature Synthesis of Shape Memory Titanium-Nickel Superelastic Alloys: A Mini-Review
Currently, the synthesis technology of porous Ti-Ni-based alloys with shape memory effect is being extensively studied and has attracted significant interest in various fields of application. Due to their unique functional properties, such materials are widely used in medicine, high-precision instrument manufacturing, as well as in aerospace and aviation technologies. However, many conventional production methods often require expensive raw materials and complex, energy-intensive equipment, which limits their industrial efficiency. To address these challenges, self-propagating high-temperature synthesis (SHS) is proposed as an alternative technology. The ability to achieve high temperatures through internally generated heat from exothermic reactions enhances the energy efficiency of this synthesis method while reducing the need for external heat sources. As a result, the obtained product exhibits structural uniformity, and the overall production costs are minimized. This scientific review comprehensively explores the potential of producing Nitinol via the SHS method, as well as the structural and functional properties of the resulting material, and the influence of synthesis parameters on material quality.
Electrochemical Recovery of Iron from Sulfuric Acid Leachates of Coal Ash
Coal ash represents a major industrial by-product containing significant amounts of iron, yet its recovery is hindered by the inert aluminosilicate matrix. In this study, a two-step approach was developed for selective extraction and electrochemical recovery of iron. Coal ash was first treated with concentrated sulfuric acid at elevated temperature, producing a leachate enriched in Fe2+ ions. The effects of Fe2+ concentration (0.1-0.5 mol/L), current density (1250-5000 A/m2), and electrolysis time (1-6 h) on recovery efficiency, current efficiency, and energy consumption were systematically investigated. Under optimal conditions (0.30 mol/L Fe2+, 2500 A/m2, 4 h), iron recovery reached 89% with a current efficiency of 65%, while energy consumption was as low as 1.8 Wh/L. XRD and SEM analyses confirmed that optimized parameters favor the formation of metallic Fe with minor magnetite content. These results demonstrate the feasibility of integrating acid leaching and electrolysis into a practical route for coal ash valorization and selective iron recovery.
Study of the Effectiveness of Antibacterial Properties of Carbonised Material Components for Use in Armour Systems
Air pollution is one of the most pressing environmental and social issues of modern times. This work presents the development of carbonized carbon-silicon sorbents based on rice husk, combining high sorption capacity with pronounced antibacterial properties. The scientific novelty of the study lies in the comprehensive investigation of the material's morphology, phase composition, and functional groups, followed by an assessment of its biocidal activity. Scanning electron microscopy revealed a transition from the disordered structure of the raw material to a porous amorphous surface after carbonization at 850 °C. X-ray diffraction analysis showed the presence of amorphous carbon with an average crystallite size of 0.5 nm, while FTIR spectroscopy confirmed the formation of Si-C bonds, associated with enhanced antibacterial activity. Biological tests against Bacillus paramycoides and Pseudomonas koreensis demonstrated growth inhibition zones of up to 38 mm and 44 mm, respectively, with an antagonistic activity index reaching 77.4. The most pronounced effect was observed against Pseudomonas koreensis, confirming the selective nature of the sorbent's antimicrobial action. The results indicate the potential of the developed sorbents as functional filtering materials for life-support systems, including in confined spaces where comprehensive protection against aerosol and biological threats is required.
Synthesis and Properties of Humic Acids Derived from Brown coal of Kuznetsk and Kumuskuduk Deposits
This article presents the synthesis and comparative characterization of humic acids extracted from brown coal deposits of Kuznetsk and Kumuskuduk in Kazakhstan. Advanced analytical techniques, including infrared (IR) spectroscopy, elemental analysis, and thermogravimetric/differential scanning calorimetry (TGA/DSC), were employed to investigate the physicochemical and structural properties of the humic acids derived from these two distinct geological sources. The results revealed significant differences in elemental composition, particularly in carbon, oxygen, and hydrogen content, which were directly related to the geological and environmental conditions under which the coals were formed. Variations in the concentration of carboxyl and hydroxyl functional groups were also identified, influencing the sorption capacity, acidity, and complexation behavior of the humic acids. Thermal analysis demonstrated differing levels of thermal stability and decomposition patterns, reflecting the structural heterogeneity of the samples. This study highlights the importance of geological origin in determining the functional potential of humic substances and supports their application in environmental remediation, agriculture, and water purification.
Anode Materials for Solid Oxide Fuel Cells: Short Review
This review paper is dedicated to the structure, properties, and development of anode materials for solid oxide fuel cells (SOFCs). In addition to traditional anodes based on Ni-YSZ composites, the review discusses advanced alternatives such as perovskite and double perovskite structures, chromites, and ceramic materials based on titanium and vanadium. It is noted that various synthesis methods – sol-gel, solid-state reaction, infiltration, and magnetron sputtering – play a crucial role in the development of new anode materials. Furthermore, it is shown that doping the anode structure with transition metals (e.g., Mo, Ni, Co, Pd) significantly enhances the electrical conductivity and catalytic activity of the material. The article also draws conclusions regarding the enhancement of electrochemical activity through the microstructural characteristics of anode layers and the expansion of the triple-phase boundary (TPB) region. Approaches to increasing the surface activity of the anode and preventing carbon deposition via nanoparticle modification and thin-layer coatings of SDC or GDC are explored. The consolidated scientific data and comparative analysis provide a foundation for designing and developing high-performance and stable anode materials capable of operating under various temperature and fuel conditions. These studies make a significant contribution to the large-scale implementation of SOFC technologies in the future and to enhancing their reliability.
Mechanochemical Processing of Natural Raw Materials and Technogenic Wastes to Obtain Thermal Insulation Materials
Re-using ash-slag waste from coal-fired power plants for thermal-insulation products offers a viable route to waste valorisation and energy saving. In this work, natural diatomite and ash-slag waste were jointly mechanochemically activated for 20 min in a «NXQM-2A» centrifugal planetary mill (powder-to-ball mass ratio 1:4) and simultaneously modified with graphite. High-energy milling destroyed residual crystalline phases, increased the amorphous aluminosilicate fraction and preserved an intrinsic pore network, which lowered the thermal conductivity of the composites to 0.10-0.12 W/m·K while raising bulk density and compressive strength (diatomite: 5.6-23.2 MPa; fly ash: 10.5-37.6 MPa). Addition of 10 wt % graphite further enhanced the hydrophobicity of diatomite – reducing water uptake by about 50% produced the minimum λ-value (0.11 W/m·K) for the ash-slag system. Conversely, 20 wt% graphite generated excessive macroporosity, lowering strength to 4-2 MPa and diminishing moisture resistance. Thus, mechanochemical activation combined with moderate graphite dosing markedly improves the thermal (lower λ) and mechanical (higher strength) performance of diatomite- and ash-based composites while simultaneously decreasing water absorption. The results confirm the feasibility of upcycling ash-slag waste into high-efficiency insulation materials suitable for building envelopes and other thermal-barrier applications.
Copyright (c) 2025 А.Е. Матен, Б.С. Садыков, А.Б. Артықбаева, А.С. Әділхан, А.О. Жапекова, А.Е. Баққара https://creativecommons.org/licenses/by/4.0
Mathematical Model of Heat Transfer and Mass Transfer During Neutralization of Powder Gases in the Fighting Compartment of Armored Vehicles
The article models the neutralization of powder gases in the fighting compartment using a pyrotechnic composition (sodium nitrate, powdered iron, activated carbon). Thermochemical pyrotechnic systems are characterized by a high reaction rate and intense gas and heat generation. Due to these properties, they are used in the reservation of machinery to create barriers that effectively separate powder gases and protect internal components from thermal and mechanical stress. The key factors of chemical neutralization efficiency are analyzed: the kinetics of oxidant decomposition, oxidation of the metal component, and thermal decomposition of carbon. A mathematical model of heat transfer, mass transfer, and chemical transformations in the interaction of gases with pyromass is proposed. Numerical analysis shows a significant decrease in concentrations of nitrogen and carbon oxides, which improves the sanitary and hygienic conditions of the crew. The developed algorithms are applicable to the design of air purification systems in armored vehicles and the creation of new pyrotechnic neutralizers.
4D is a four-dimensional mathematical model
Comparative Study of Scandium Leaching from Coal Ash with Mineral and Organic Acids
Scandium (Sc) is a critical element with applications in high-performance alloys and energy technologies. Yet, its recovery from secondary sources such as coal ash remains challenging due to low concentrations and strong association with refractory aluminosilicates. This study evaluated the leaching behavior of Sc from coal ash using mineral (HCl, H2SO4) and organic (citric, malic, oxalic, tartaric) acids under identical conditions (80 °C, 0.5 M, solid-to-liquid ratio 1:20). Mineral acids achieved the highest extraction yields (82-90%). Still, they exhibited poor selectivity, with extensive co-dissolution of Fe and Al. Among the organic acids, citric acid provided the best balance between recovery and selectivity, yielding up to 68% Sc with Fe and Al dissolution below 26%. A complete factorial design varying citric acid concentration (0.1-1.0 M) and pulp density (25-100 g/L) revealed that both efficiency and selectivity could be tuned, with optimal conditions (0.5 M, 25 g/L) resulting in 64% Sc recovery and selectivity factors Sc/Fe = 6.40, Sc/Al = 3.76.
Custom Ultrasonic Spray Pyrolysis Equipment for the Scalable Synthesis of LiFePO4 Cathode Materials
Lithium iron phosphate is a promising cathode material for lithium-ion batteries owing to its safety, long cycle life, and environmental compatibility, but its performance strongly depends on the synthesis route. In this work, we report a custom-designed ultrasonic spray pyrolysis system equipped with a six-zone programmable furnace and a heated electrostatic precipitator for scalable and controlled LFP/C synthesis. Compared with conventional single-zone USP setups, this apparatus enables staged droplet-to-particle transformations, suppressing hollow morphologies and improving precursor uniformity. LFP/C powders synthesized in the 400-600 °C range exhibited poorly crystalline or partially amorphous structures as-sprayed, which transformed into phase-pure olivine LiFePO4 after annealing at 600 °C for 3 h under Ar. SEM revealed that spherical, submicron precursor particles (~200 nm ─ 1 µm) with smooth surfaces were produced directly by USP, while post-annealing preserved the morphology but introduced coarser textures and surface porosity. Such microstructural evolution is expected to balance tap density and Li⁺ transport pathways, consistent with prior studies of USP-derived LFP/C. Comparative analysis with two-phase nozzle and flame spray pyrolysis systems shows that the combination of gradient thermal control and electrostatic deposition in our setup improves the quality of the resulting powders and provides a promising combination of laboratory precision and potential scalability. These results demonstrate that the custom USP approach is an efficient and flexible platform for producing high-quality LFP/C cathode powders with controllable morphology and crystallinity.
Preparation of the Composition of Composite Materials Based on Polymers and Solid Carbon Materials
The use of household polymer waste in bitumen modification is one of the promising areas that allows providing the road surface with maximum resistance to fatigue failure, resistance to temperature changes in daily and seasonal cycles and a direction in solving environmental problems. In addition, using polymer waste can solve the problem of the increased cost of bitumen modified with polymers. In this research work, the compositions and physical-chemical characteristics of bitumen, polymer-bitumen binders and coal coke are studied. The detailed chemical composition of coal coke was studied using IR spectroscopy and thermogravimetric analysis. Addition of microdispersed coke during bitumen modification shows improvement of the characteristics of the obtained product similar to polymer-bitumen binders. Polymer-bitumen binder with addition of polymer waste and polymer modifier Elvaloy meets the requirements of ST RK 2534-2014 for BMP 50/70 in terms of its main indicators. During the process of bitumen modification with polymer waste, polymer particles physically react with high-molecular components (asphaltenes, resins and polyaromatic compounds), which affects the physical and mechanical properties of the bitumen binder: the softening temperature increases, the penetration and ductility values decreased. Addition of microdispersed granulated coke powders for modification of road bitumen meets the requirement of PBB 40 according to GOST R 52056-2003.
Synthesis Methods of MXenes from MAX Phases: A Comparative Review of Etching Methods and Their Implications
MXenes are a class of two-dimensional (2D) materials composed of transition metal carbides, nitrides, and carbonitrides. Due to their high electrical conductivity, hydrophilicity, and tunable surface chemistry, they have gained significant attention. These materials are typically synthesized from layered ternary precursors known as MAX phases, with the general formula Mn+1AXn, where M is an early transition metal, A is a group 13 or 14 element, and X is carbon and/or nitrogen. The transformation from MAX to MXene occurs via selective etching of the A-layer. Choosing an appropriate synthesis and etching strategy plays a critical role in determining the structural and functional properties of the resulting MXene. This review provides a comprehensive analysis of recent advances in the synthesis of MAX phases and the production of MXene materials. Particular focus is placed on etching methods ─ such as hydrofluoric acid (HF), in situ HF (LiF + HCl), molten salts, and electrochemical techniques ─ and their effects on MXene morphology, surface terminations, and functional properties. Comparative analysis reveals that each method has distinct advantages and limitations in terms of safety, scalability, and product quality. The review also highlights current challenges, including the need for fluorine-free and environmentally safe etching processes and the importance of controlling surface terminations. Finally, future directions are proposed for adapting MXene synthesis routes for use in next-generation energy storage systems, catalysis, environmental remediation, and electronics.
In Situ Polymer Electrolyte Coating for Lithium–Sulfur Batteries
The transition from liquid electrolytes to solid-state electrolytes represents a key strategy for improving the safety and energy efficiency of lithium-sulfur (Li-S) batteries. However, poor interfacial contact and high resistance at the electrode-electrolyte interface remain critical barriers to commercialization. In this study, we report an in situ coating approach, where a crosslinkable polytetrahydrofuran-based solid polymer electrolyte (aPTHF-SPE) is directly formed on the surface of C@S cathodes via UV-curing. SEM and EDS analyses confirm the formation of a uniform polymer layer with a thickness of 35-46 μm, ensuring intimate interfacial contact and reduced void formation. Electrochemical tests demonstrate that the coated cathodes deliver an initial discharge capacity of ~250 mA·h·g-1, with subsequent cycles exhibiting improved stability due to enhanced ionic transport and electrode activation. Despite gradual fading after extended cycling, the strategy significantly improves the electrode-electrolyte interface compared to uncoated cathodes. These findings highlight in situ polymer electrolyte coating as a promising and scalable method for addressing interfacial challenges in solid-state Li-S batteries, paving the way toward safer and higher-performance energy storage systems.
TiO2 Nanosheet Based Photocatalysts with Oxygen Vacancies for Enhanced Hydrogen Evolution Reaction Activity: Synthesis and DFT Calculations
This work, we propose an efficient method for synthesizing TiO2 nanosheets on titanium foil via plasma electrolytic oxidation (PEO) followed by hydrothermal growth of nanostructures. Density functional theory (DFT) calculations were conducted to optimize the material’s electronic properties and enhance its activity in the photocatalytic hydrogen evolution reaction (HER) through Mo doping. The PEO method forms a porous TiO2 seed layer with strong adhesion to the substrate. On this basis, in a multi-stage process in situ nucleation of sodium titanate nanosheets occurs, followed by their transformation into TiO2 nanosheets with a high specific surface area. Oxygen vacancies formed in the anatase phase play a key role in the adsorption of oxygen-containing ions and the activation of photocatalytic processes. Furthermore, DFT modeling confirmed that Mo doping and surface modification resulted in a decrease in the band gap (from 2.67 to 2.4 eV) , which contributed to the improvement of the photocatalytic activity and stability of the system. The proposed approach represents a promising strategy for scalable synthesis of monolithic, nanostructured TiO2 photocatalysts with robust adhesion to titanium substrates.
Hydrogen Storage Technologies: Achievements, Challenges, and Development Prospects
Hydrogen is considered one of the most promising energy resources of the 21st century due to its environmentally friendly use and potential for integration into sustainable energy. However, the widespread adoption of hydrogen energy is hampered by the lack of efficient and safe storage technologies. This paper presents an overview of modern approaches to hydrogen storage with an emphasis on physical and chemical methods, as well as the use of nanostructured porous materials. Traditional storage technologies are considered ─ in the form of compressed gas and liquid hydrogen, which have already found practical application, but are characterized by high energy consumption, limited bulk density and safety issues. Attention is paid to the storage of hydrogen in metal hydrides, which have an acceptable potential capacity in practical applications. However, their use is limited by the need for high desorption temperatures, slow kinetics and low reversibility of processes. New areas associated with the use of nanoporous carbon, including materials obtained from biomass and non-traditional raw materials, are considered. High specific surface area, developed microporous structure and the possibility of functional modification make such materials promising for adsorption storage of hydrogen. Examples of experimental works demonstrating the achievement of capacity over 10 wt.% under optimal conditions are given. It is concluded that further development of hydrogen technologies requires an integrated approach, including the improvement of existing systems, the search for new materials and the application of sustainable technologies for the use of renewable raw materials.
Surface modification of aramid films in oxygen and argon plasmas
Processes of plasma modification and destruction of aramid films have been studied. The films were treated in argon and oxygen low-pressure direct current discharges at pressures of 30 and 150 Pa and discharge currents of 20 and 50 mA. Treatment in oxygen plasma was shown to be an effective method for increasing surface wettability, oxygen content in thin surface layer and surface roughness. These effects are less after the treatment in argon plasma.
Copyright (c) 2014 К.А. Джбааи, В.А. Титов, Т.Г. Шикова https://creativecommons.org/licenses/by/4.0
RH-promoted carbon catalysts to obtain clean components of motor fuels
The increased content of aromatic hydrocarbons impairs environmental and technological properties of fuels: increased tendency towards carbon formation; increased particulate emissions from the engines. In order to reduce the content of aromatics in the oil fractions we use dearomatization process performed based on the hydrogenation of benzene to cyclohexane over Rh-promoted catalyst. The process is conducted at a rhodium catalyst that operates under mild conditions and has greater selectivity for compounds with a terminal double bond. In this work we developed synthesis method of carbon matrix and active ingredients promoted methods. Synthesized Rh carbon catalysts inflicted on clay and the carbonized apricot pits. The influence of Rh content in the hydrogenation of benzene. Identified the optimal conditions for the hydrogenation reactions of aromatic hydrocarbons over Rh catalysts inflicted on various matrixes. Investigated the physic-chemical characteristics of the promoted carbon materials.
Copyright (c) 2014 С.К. Танирбергенова, Н.К. Жылыбаева, А. Темiрхан, Г.М. Наурзбаева, Г.М. Молдажанова, З.А. Мансуров https://creativecommons.org/licenses/by/4.0
Research on graphene, formed in the vapor atmosphere aromatic hydrocarbons, method EPR spectrum
The article shows the procedure for the preparation of graphene and carbon nanotubes included in the carbon films formed in simple, organic, reactive magnetron sputtering of graphite in an atmosphere of sublime vapor aromatic hydrocarbons including naphthalene. Net carbon molecular structure of aromatic hydrocarbons coin-cides with the graphene carbon grid. The resulting film structures were investigated by atomic force microscopy and found a tape of graphene and carbon nanotubes. This investigation has shown that when studying the EPR spectrum of the carbon film on the glass substrate, it was found that the film consists of a fairly intense line characteristic graphene. The evidence from this study suggests that there is a contribution of the EPR line of nanotubes. This paper gives that the results of investigation obtained samples by this technique and discuss them.
Copyright (c) 2014 Ю.А. Рябикин, Б.А. Байтимбетова, Б.М. Верменичев https://creativecommons.org/licenses/by/4.0
Investigation of the conductivity of carbon nanotubes obtained by magnetron sputtering graphite using aromatics hydrocarbons
The article analyses the dependence of the conductivity of carbon nanotubes on their radius obtained by simple, organic, reactive magnetron sputtering of graphite in an atmosphere of sublime steam aromatic hydrocarbons. Based on the analysis of the conductivity of the carbon nanotube grows with its radius. The results of this investigation show that is increasing the radius of carbon nanotubes grows the number of atoms in a plane which forms a nanotube according to the current flow area becomes larger and the conductivity increases.
Copyright (c) 2014 А.А. Аскарова, Б.А. Байтимбетова, В.Э. Никулин https://creativecommons.org/licenses/by/4.0
Study gliding rotating discharge at atmospheric pressure
This paper considers the possibility of creating a long-life-time plasma generator based on a gliding rotating discharge. Influence of geometrical and dynamic parameters of systems with gliding rotating discharge on the nature of the discharge was investigated. Transverse to the electric field rotating airflow was provided the gliding and rotating discharge.
Copyright (c) 2014 Д.Л. Чернолуцкий, В.В. Колган, В.Я. Черняк, О.А. Недыбалюк, В.В. Юхименко, В.А. Шаповал, Е.В. Соломенко, М.О. Якимов https://creativecommons.org/licenses/by/4.0
Getting the melt of basalt in plasma electromagnetic reactor
In this paper, the advantages of the use of basalt fibers and their products in the building industry and power system. The results of calculations of the melting process of Kazakhstan basalts. Calculations have shown that the gaseous products of the process and condensed contaminants are absent. The advantages of electric melting mineral rocks, including basalt, compared to ore-smelting furnaces. The results of experimental heats of basalt in a reactor with electromagnetic stirring of the melt are demonstrated. The prospects of melting basalt and obtain mineral fiber for small modular units that are based on electromagnetic reactor (EMR) are shown. It was found that the specific energy consumption for a homogeneous melt basalt does not exceed 1,1 kW·h/kg, which compares EMR favorably to traditional melting devices (cupola, ore-smelting furnaces and gas furnaces, electric furnaces) in which this figure is several times higher.
Copyright (c) 2014 В.Г. Лукьященко, В.Е. Мессерле, А.Б. Устименко, К.А. Умбеткалиев, В.Н. Шевченко, З.А. Мансуров, С.Х. Акназаров https://creativecommons.org/licenses/by/4.0