This study presents the synthesis of zeolites derived from coal fly ash (CFA) using the fusion-assisted alkaline hydrothermal method. The zeolites were synthesized by combining CFA and NaOH at a molar ratio of 1:1.2 under fusion temperatures of 500, 600, and 700 °C. Subsequently, the obtained zeolites were subjected to further modifications through the incorporation of magnetic (Fe3O4) and silver (Ag0) nanoparticles (NPs). The Fe3O4 NPs were introduced through co-precipitation of Fe(NO3)2 and FeCl3 at a molar ratio of 1:1, followed by thermal curing at 120 °C. On the other hand, the Ag0 NPs were incorporated via ion exchange of Na+ with Ag+ and subsequent reduction using NaBH4. The synthesized porous materials exhibited the formation of zeolites, specifically analcime and sodalite, as confirmed by X-ray diffraction (XRD) analysis. Additionally, the presence of Fe3O4 and Ag0 NPs was also confirmed by XRD analysis. The elemental composition analysis of the synthesized nanocomposites further validated the successful formation of Fe3O4 and Ag0 NPs. Nitrogen porosimetric analysis revealed the formation of a microporous structure, with the BET surface area of the zeolites and nanocomposites ranging from 48.6 to 128.7 m2/g and pore sizes ranging from 0.6 to 4.8 nm. The porosimetric characteristics of the zeolites exhibited noticeable changes after the modification process, which can be attributed to the impregnation of Fe3O4 and Ag0 NPs. The findings of this research demonstrate the effectiveness of the fusion-assisted method in producing synthetic zeolites and nanocomposites derived from CFA. The resulting composites were evaluated for their potential application in the removal of mercury ions from aqueous solutions. Among the samples tested, the composite containing Ag0 NPs exhibited the highest adsorption capacity, reaching 107.4 mg of Hg2+ per gram of composite. The composites modified with Fe3O4 NPs and Ag/Fe3O4 nanocomposites displayed adsorption capacities of 68.4 mg/g and 71.4 mg/g, respectively.
The influence of certain factors on the kinetics of the process of obtaining aluminum borides (burning rate, ingot formation, and phase separation) was investigated. In this study, we report the registration of diboride using the SHS protocol. The synthesis of aluminum diboride from boric anhydride occurred by the aluminothermic method. The initial components were boron trioxide and aluminum in the form of powders. Researchers paid special attention to the degree of grinding of the charge fluxing substances. The influence this had on the rate of development of the degree of charge concentration was studied. To calculate the degree of charge, a composition was chosen according to the speed obtained from a number of experiments where melting was carried out with the following charge densities in g/cm3: 0.80; 1.08; 1.18; 1.74. The method of melting was ignition from above. The experimental results allowed us to conclude that the nature of the change in the combustion rate of the system, where there was an excess of the reducing agent in the charge, is the same. An increase in the combustion rate, where there was an excess of aluminum of up to 20%, was likely due to the fact that the reaction area of the charge components increased. In addition, an increase in speed can be explained by a decrease in heat losses due to a reduction in the melting time. With an increase in excess aluminum above 20% of the stoichiometry, the observed decrease in the combustion rate can be explained by a decrease in the specific heat of the process due to the melting of the excess aluminum, which played the role of a ballast.
This paper is the continuation of our previous paper. In this work, we optimized the synthesis of aluminum borides by the SHS method. The purpose of the research was to develop the foundations of waste-free technology. The initial components were powders of boric anhydride (B2O3), aluminum (Al), the oxide-heating additive (KNO3), various fluxing additives, including mixed ones. The optimal ratios of the initial components for increasing the yield of aluminum boride with a high boron content and obtaining slag suitable for the production of high-alumina clinkers were determined. Studies have shown that the development of a waste-free technology for producing aluminum borides by the method of self-propagating high-temperature synthesis (SHS) is possible and yields target (alloy) and by-product (slag) products that meet the requirements for chemical and phase composition.
This article discusses the combustion of high-energy systems based on the oxidizers ammonium nitrate, potassium nitrate, and a mixture of highly active aluminum grade PAP-1 under conditions of a deficiency or excess oxidant α, under a pressure reduction in the range of 0.1–3 MPa. The objective of this study is to develop materials for the production of high-energy compositions based on oxidizers of ammonium and potassium nitrate, fuel binder, and metallic fuel in the form of aluminum powders ASD-6 and PAP-1. The influence of the amount of excess oxidizer, the amount of metallic fuel, and the grade of aluminum on the rate and completeness of combustion of a high-energy composition have been studied. Experiments were carried out on the studied high-energy systems, depending on the grade of aluminum used and the excess of the oxidizing agent α, and the influence of pressure on the burning rate. The compositions of high-energy compositions based on highly active aluminum with the highest combustion rate of mixtures and combustion completeness were determined.
When using hemosorbent laminar flow, a large active area of sorbents is used, the trauma of the blood corpuscles decreases dramatically, the ash content of the saline solution is absent. One of the methods of solving environmental problems is to develop various materials based on industrial waste. In the article, the method of obtaining carbonized rice husks is described, the adsorption capacity for methylene blue was measured for the obtained sample, the morphological structure was examined, comparative analysis with analogs was carried out. The authors carried out research work, such as collecting information, selecting methods, conducting analysis, processing the results. Granular hemosorbents that have been used until recently penetrate the blood-forming elements, creating a mechanism for thrombosis that violates the integrity of the erythrocyte membrane.
The article presents the results of developing carbon-silicon sorbents that demonstrate high efficiency in capturing various types of dust particles, along with partial antibacterial activity. Dust particles ranging from 0.65 to 150 microns were effectively retained by the sorbent, with organic dust capture efficiency varying between 74% and 98%, making these sorbents suitable for air purification in highly polluted indoor environments. The antibacterial activity was tested on Bacillus paramycoides and Pseudomonas koreensis strains using the diffusion method on a solid nutrient medium. Testing showed that sorbent samples with different concentrations of the active ingredient exhibited varying degrees of bacterial growth suppression, with Sample No. 2 demonstrating the highest activity. Optimizing the sorbent composition and increasing the concentration of active components may enhance its antibacterial properties. These sorbents hold great potential for use in air purification systems with additional protection against bacterial contamination, making them promising for environments with high standards for air hygiene and cleanliness.