The effect of the mineralogical form and chemical composition of siliceous and calcareous components on the physicochemical processes of calcium silicate and hydrosilicate formation has been investigated under two-stage wollastonite synthesis conditions. It was established that the degree of SiO2 crystallinity and the presence of foreign impurities in the raw materials have a decisive influence on the formation of the tobermorite phase during hydrothermal treatment. The patterns of microstructure formation of the synthesized products have been studied. It has been shown that amorphous varieties of silica form more crystallized calcium hydrosilicates than quartz. Using XRD and SEM methods, it has been established that the transformation of tobermorite into beta wollastonite occurs within the temperature range of 900- 1100 degrees C. As the burning temperature increases, the degree of wollastonite crystallinity and crystal sizes increase. The optimum temperature for obtaining beta-wollastonite with a distinct columnar morphology and crystal sizes of 2-5 mu m lower temperatures compared to classical methods of solidthe use of available secondary raw materials.
In this study, new complexes containing a multisubstituted aryl imidazole ligand, namely (2-(1H-phenanthro[9,10-d] imidazol-2-yl) phenol, have been synthesized. Imidazole ligand L was synthesized via a condensation reaction between diketone (9,10-phenathroquinone), aromatic aldehyde (2-hydroxy benzaldehyde), and ammonium acetate in the presence of glacial acetic acid as a solvent and catalyst. Subsequently, metal complexes were prepared by reacting this ligand with transition metal salts, including Fe (II), Cu (II), Ni (II), and Co(II) chlorides, in an appropriate solvent like ethanol under controlled temperature and stirring conditions to ensure the formation of stable complexes. The structures of the ligands and their metal complexes were characterized utilizing different spectroscopic techniques, such as (UV-Vis), FT-IR, 1H NMR, 13C NMR spectroscopic, mass spectroscopy, magnetic susceptibilities, molar conductivity, and elemental analysis (C. H. N). It is observed that the synthesized complexes have tetrahedral and octahedral geometrical structures. The ligand and its complexes play important roles in supramolecular assemblies because they can also provide bidentate N-donor sites for chelating with metal ions to form a bridge ligand. The biological evaluation was performed using the agar well diffusion method to assess the antibacterial activity of both ligand and metal complexes against selected Gram-positive and Gram-negative bacterial strains. The results revealed that the free ligand and its metal complexes displayed significantly enhanced antibacterial activity compared to the reference drug. Antioxidant potential was assessed using the DPPH radical scavenging assay; metal complexes generally showed higher radical inhibition percentage. Hemolytic activity was evaluated on human red blood cells to determine cytocompatibility. The findings showed that the ligand and metal complexes exhibited low to moderate hemolytic activity, indicating acceptable biocompatibility for potential biomedical applications.
Waste tires (WT) are the main component of industrial rubber waste. One of the promising methods for rational utilization of WT is the process of their pyrolysis-a thermochemical process during which thermally unstable organic components that make up WT decompose into gaseous, liquid, and solid products at temperatures of 300-900 degrees C. Pyrolysis combines waste processing with energy and fuel recovery. Liquid pyrolysis products (LPP) can be considered the main products of WT pyrolysis, which are obtained as a result of condensation from volatile fractions of WT pyrolysis. They are a dark, opaque liquid with a characteristic pungent odor and consist mainly of aromatic and unsaturated compounds; therefore, their use as fuels requires extensive processing. This paper describes initial (exploratory) studies on the feasibility and expediency of using the thermal oxidation treatment process to purify the gasoline fraction <= 200 degrees C obtained after atmospheric distillation of LPP. Oxidation was carried out in a batch reactor with air in the presence of water. The composition of the raw material mixture and its phase state during the process were investigated and calculated, and the pressure and raw material: air ratio were justified. These studies will serve as the basis for a future detailed analysis of the thermal oxidation of the gasoline fraction obtained from WT pyrolysis, to reduce its content of undesirable compounds (reactive unsaturated, sulfurous, and high-boiling aromatics).
This research examines the rheological and density properties of starch-based compositions with variable ratios of components, focusing on potato and corn starches. Using glycerol as a plasticizer, the study evaluates the impact of concentration, starch content, and thermal conditions on the density, rheological, and structural behavior of the compositions. A simplex lattice method was employed to derive empirical models predicting the performance of these systems under diverse processing parameters. Results reveal significant differences between the structural properties of potato and corn starch-based materials, emphasizing the potential of these compositions in developing biodegradable products. The results provide actionable guidance for optimizing starch-based materials in food technology, packaging, pharmaceuticals, and environmentally sustainable manufacturing.
Wastewater containing dyes at certain levels can be harmful to the environment. Removal of dye pollutants in wastewater can be done by the adsorption method. Fly ash, solid waste from coal combustion, can be utilized as a dye adsorbent. Modification of fly ash with alkali (NaOH solution) and magnetite (Fe3O4) can increase the adsorption capacity and facilitate separation. In this paper, fly ash was modified with alkali and magnetite and then applied as an adsorbent for naphthol blue black (NBB) dye. The highest efficiency of NBB dye adsorption by alkali and magnetite-modified fly ash was 99.17 %. Adsorption followed the Freundlich isotherm model and the pseudo-second-order kinetics model.
