SOUTHERN JOURNAL OF SCIENCES

A new phase of the (CuAlSe₂)_1-x(TaSe)_x alloy system was synthesized by the melt and annealingtechnique and studied by SEM, DTA, and XRPD techniques. Its structure has been refined by the Rietveld methodusing X-ray powder diffraction data. The new alloy corresponds with the stoichiometry Cu_0.4Al_0.3TaSe₂. Thiscompound crystallizes in the hexagonal space group 𝑃6ത𝑚2 (Nº 187) with a MoS₂-type structure, and unit cellparameters a = 3.455(2) Å, c = 13.423(4) Å, V = 138.7(1) Å3, Z =2. The crystal structure is based on the MoS₂-type of stacking of TaSe₂ layers with a partial ordering of Cu and Al cations over the tetrahedral sites. The powderpattern was composed of 63.1% of the principal phase Cu_0.4Al_0.3TaSe₂ and 29.9% of CuAlSe₂, 7.0% of TaSe₃, asthe secondary phases. 

Background: This study explores the potential use of biomass residues from soybean pressing via static pyrolysis to produce carbonaceous materials for pesticide adsorption. It emphasizes concerns regarding the environmental impact of agroindustrial waste and the persistent nature of pesticides in soil and water systems. Aims: To investigate the efficacy of biochar obtained from soybean waste in adsorbing pesticides. Specifically, to analyze the gas products generated during pyrolysis and characterize the obtained carbonaceous material for its adsorption capabilities. Methods: Soybean residue underwent static pyrolysis at various temperatures and durations. Gas analysis utilizing FTIR spectroscopy identified the gaseous products generated during the pyrolysis process. The obtained biochar underwent successive washes and characterization through FTIR spectra comparison with commercial activated carbon. Through absorption assays, using UV-VIS spectroscopy, investigations were conducted on the solid biocarbon fractions to evaluate their capacity for absorbing pesticides. Results: Gas Analysis: The study revealed the production of volatile organic compounds (VOCs) and highlighted the prevalence of mono-carbon compounds with increased temperature and pyrolysis time. The analysis demonstrated consistent carbon mass percentages across different reaction conditions. Characterization of Biochar: Comparison with activated carbon indicated structural similarities with heightened intensity in certain bands, suggesting the presence of incomplete cellulose cracking in the obtained biochar. Regarding the Chlorothalonil, Atrazine and DIcamba remotion, notably, the concentration of Chlorothalonil in a 7:3 water: acetonitrile solution decreases by 77 % through adsorption on the carbons. Discussion: The investigation examined the adsorption efficiency of the biochar for Chlorothalonil, Atrazine, and Dicamba from aqueous solutions. Chlorothalonil exhibited substantial retention by the biochar, while Atrazine showed comparatively lower adsorption effectiveness. Remarkably, Dicamba did not demonstrate retention by either the biochar or activated carbon. Conclusion: The study underscores the potential of pyrolyzed soybean waste for pesticide adsorption, particularly highlighting Chlorothalonil's strong affinity with the carbonaceous structure. Further research is needed to optimize adsorption properties and explores potential enhancements of these materials through additional treatment methods, offering promising avenues for environmental remediation.

Introduction: Thermal insulating coatings are increasingly being introduced into construction practice for internal and external finishing enclosing structures and pipelines. Thermal insulation coatings are usually made based on polymer binder and mineral fillers. The durability and stability of the properties of heat-insulating materials depend on the type of binder. As a rule, polymers are used as a binder: epoxy resin; silicone rubber; urea-formaldehyde resins; aqueous dispersed polymers - styrene-butadiene, polyvinyl acetate, and acrylate (acrylic and styrene-acrylic). The quality indicator of binders can be assessed by the influence of the seasonality of climatic impact, and as a result, the best elastic strength characteristics of binders can be established after one month to a year of field tests. Aim: To determine the influence of climatic factors on the change in the elastic-strength indicators of epoxy polymers binders used in liquid thermal insulation coatings. Methods: A tensile testing machine of the AGS-X series with the TRAPEZIUM X software was used for mechanical tests. The tests were carried out in accordance with GOST 11262-2017 (ISO 527-2: 2012) "Plastics. Tensile test method". Results and Discussion: The paper discusses the results of experimental studies of the compositions of polymer binders and their resistance to various climatic factors, which will later be used as a polymer binder for thermal insulation coatings based on fine mineral granular systems. Conclusions: When analyzing the changes in the characteristics of polymer samples after exposure to climatic factors, it was found that compositions based on Etal-247 epoxy resin, cured with amine hardeners Etal-1440N, Etal-1460, Etal-1472, and Etal-45M, demonstrate the best elastic strength characteristics after one year of full-scale tests. The high stability of the indicators under consideration allows us to conclude that the use of Etal-247 resin as a base leads to creating of the most climate-resistant epoxy coatings.