Том 70, № 3 (2025)

Natural and synthetic aluminosilicates currently have a wide range of applications. Silicon-containing wastes of rice production are of great interest as a source of raw materials for their production. The purpose of this work is to synthesize micro- and mesoporous materials from rice husk by templat method using PEG-6000. The obtained samples were investigated by differential thermal analysis and IR spectroscopy, which showed the introduction of PEG into the structure of potassium aluminosilicate during sol-gel synthesis. The specific surface area of the samples and pore size distribution were determined by low-temperature nitrogen adsorption, according to which it was found that the pore radius increased from 100 to 200 Å during sol-gel synthesis when the PEG concentration was changed from 5 to 20 mmol/L. The study of the surface of the samples by scanning electron microscopy showed that the introduction of templat changes their surface morphology and promotes structuring.

The purpose of the presented work was to study the possibility of mechanochemical synthesis of polyaluminomodiphenylsiloxanes. For the first time, diphenylsilanediol and tributoxyaluminium were used for synthesis under conditions of mechanical activation. It was found that alumodiphenylsiloxanes with a Si/Al ratio close to the set one are formed, and an increase in the activation time leads to an increase in the rate of homocondensation of the initial diphenylsilanediol and, as a result, an increase in the Si/Al ratio. Using IR- and NMR-spectroscopy, it was found that the aluminum atom forms a polymer aluminosiloxane chain with silanediol, in which butoxyl groups are preserved. It is shown that the obtained compounds have significantly lower thermal stability than spatially branched organometallic siloxanes. The compounds obtained in the work are characterized by modern methods of analysis.

The paper presents the synthesis of layered complex carbide of the composition (Cr,V)C using reactive spark plasma sintering (SPS-RS) and hydrothermal acid etching. Using SEM and TEM, a detailed study of the macro- and nano-structure at each stage of MAXene synthesis was carried out. The presence of characteristic features of the formation of two-dimensional carbide in the form of particles and fragments of a multilayer structure at the macro- and nanolevel was confirmed. Using EDS and XRD, the elemental and phase composition of the samples was studied, as a result it was found that the initial expected MAX-phase Cr₂VAlC₂ in the composition of the sample obtained by SPS is absent. At the same time, a phase of mixed bimetallic carbide (Cr,V)C was detected at all stages of synthesis, for which the crystal lattice parameters, including the unit cell volume, change significantly after acid etching. Obvious changes in the bulk and crystalline structure of (Cr,V)C correspond to the formation of two-dimensional nanoparticles in the synthesized material. The magnetic characteristics study showed that all samples have magnetic hysteresis with relatively low values of coercivity and remanence to saturation magnetization ratio. Low-temperature measurements showed a slight increase in magnetic moment with decreasing temperature for the sample obtained under reaction SPS conditions before acid etching in HF, without significant changes in magnetic behavior of the samples.

In recent years, with the growing popularity of electric vehicles and other battery-powered devices, there has been a significant increase in demand for lithium-ion batteries (LIBs). These batteries have become the main power source for most portable devices and electric vehicles, such as the Nissan Leaf. However, with the increase in LIB production and consumption, there is not only the question of ensuring their efficient production but also the need for environmentally safe recycling. The recycling process of used LIBs involves extracting valuable components such as lithium, cobalt, nickel, and manganese. Efficient recycling of cathode materials becomes particularly important as it allows both the reuse of these metals in new battery production and reduces the need for resource mining. Manganese (Mn), which can be extracted during LIB recycling, not only plays a crucial role in battery production but can also serve as a basis for synthesizing new materials, such as the Mn3AlC MAX phase. Manganese MAX phases represent a class of two-dimensional materials that are attracting increasing attention from researchers due to their unique properties. Thus, lithium-ion battery recycling not only solves the waste disposal problem but also creates opportunities for developing new materials.

The reactions of coordinated ligands in acetylacetonate complexes of chromium and boron difluoride were studied by chromatograph mass spectrometry. It was found that bromo- and thiophenyl-substituted acetylacetonates of boron difluoride, unlike chromium complexes, do not interact with thiophenol. The interaction of thio-substituted chelates with SO₂Cl₂ also occurs differently. For chromium complexes, the reaction is accompanied by the replacement of the thioalkyl or thioaryl substituent by a chlorine atom. Thioethyl-substituted acetylacetonate of boron difluoride reacts with SO₂Cl₂ like aromatic analogues with chlorination of the ethyl group. Thioaryl-substituted acetylacetonate of boron difluoride does not react with SO₂Cl₂. In addition, it was found that bromo- and thiosubstituted chromium acetylacetonates react with sulfenyl chlorides with the replacement of the α-substituent by a chlorine atom. It was suggested that the difference in the reactivity of chromium acetylacetonates and boron difluoride is due to different charge distributions in the chelate cycle. The significant electroacceptor character of the BF₂ group leads to the appearance of a positive charge on the substituent associated with the chelate cycle of the boron complexes.

A new method of creating composite sorption materials based on mixed K-Co and K-Cu ferrocyanides using polyethylene is proposed. The uniqueness of this method lies in the hydrophobisation of the material by integrating polyethylene fibres into the ferrocyanide structure. The surface morphology and structure of the obtained sorbents were investigated by scanning electron microscopy, X-ray phase analysis and low-temperature nitrogen adsorption. The peculiarities of extraction of micro- and macro concentrations of Cs+ cations and 137Cs radionuclide from sea water under static conditions were studied. The approximation of experimental sorption data using the Langmuir and Freundlich equations has been carried out, and the values of limiting sorption Gmax and adsorption equilibrium constant Kl have been calculated. It is demonstrated that the sorbents synthesised with the addition of polyethylene have the best sorption characteristics, achieving up to 99% purification of seawater from caesium ions. The average distribution coefficient of caesium in seawater is 3.8×10^4 ml/g at a solid-to-liquid phase ratio of 1000 ml/g, which indicates the prospects of their application for purification of seawater from radiocaesium.

Currently, there is an intensive growth in the use of polymer composite materials in all areas of industry, which is due to their unique properties—high strength, lightness, corrosion resistance. In connection with the development of new technologies, there is a need to create a new class of environmentally friendly materials that provide efficient and cost-effective use of raw materials. This paper considers synthetic nanostructured aluminosilicates with a given Si / Al ratio of 1; 3; 5 as modifiers of polytetrafluoroethylene. The phase, elemental composition and thermal behavior of the synthesized compounds are studied. It was found that the use of aluminosilicates contributes to an increase in tensile strength by 40% and relative elongation at break by 70% relative to the original polymer matrix. The introduction of aluminosilicate is accompanied by an increase in wear resistance by 521 times. Thus, a new class of modifiers for polymer composite materials has been synthesized.

The article presents a study on obtaining silicon carbide ceramics, including those with a reinforcing additive (10 wt. % SiC_w whiskers), and metal-ceramic composites with a permanent connection based on this ceramics and heat-resistant alloy ZhS6U-VI using spark plasma sintering technology. The dynamics of SiC powder consolidation under SPS conditions, as well as the phase composition, structure, density and microhardness of the formed samples of SiC ceramics and its reinforced form SiC/SiC_w are studied. A method for obtaining metal-ceramic composites with a permanent connection based on the obtained samples of ceramics and heat-resistant alloy ZhS6U-VI under SPS conditions is implemented. SEM and EDS methods showed that obtaining composites with defect-free boundaries of permanently connected layers of ceramics and heat-resistant alloy is achieved by forming intermediate layers of Ti-Ag and Ni-Ag binders, as well as a damper layer of Mo to compensate for a significant difference in CTLE’s values. The structural integrity of the composites was studied using electron microscopy and X-ray microtomography. As a result, it was found that the composition of SiC ceramics without the addition of SiC_w whiskers is more structurally homogeneous and less brittle for obtaining a SiC—ZhS6U-VI composite with a permanent connection using the SPS technology.

Paint coatings with optimal performance properties are an important element in the safety and efficiency of marine and river vessels, as well as other objects exploited in the aquatic environment. In this work for modification of paint and varnish coatings we used a material based on calcium hydrosilicate, obtained by hydrothermal method from technogenic waste in the form of borogypsum. The synthesis product with specific surface 155.2 m²/g and density 3.1 g/cm3 is characterized by the presence of phases of calcium sulfate, tobermorite and xonotlite and consists of mainly from needle particles. The influence of calcium hydrosilicate, partially replacing calcium carbonate, on the properties of paint coatings based on acrylic copolymer has been studied. Physical and mechanical properties, antifouling effect, water absorption and erosion rate of paint coatings were studied.The results of the study showed the efficiency of calcium silicate use to improve the physical and mechanical properties of coatings: an increase in strength by 1.5 times was found. At the same time, the addition of calcium hydrosilicate at partial replacement of calcium carbonate does not decrease the antifouling effect.