The review is devoted to dispersed powdery porous (including supported) double and ternary metal alloys. Various approaches to the synthesis of these alloys, as well as modern areas of their practical application, are considered. An analysis of the relevance of the study of highly dispersed alloys and the feasibility of developing new methods for their production is presented.
Effect of ionic liquid 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide on the extraction of U(VI), Th(IV), and lanthanides(III) from nitric acid solutions with phosphorylureas RR'P(O)NHC(O)NHC8H17-n that differ in the nature of substituents at the phosphorus atom has been studied. A considerable synergistic effect has been revealed on the extraction of metal ions in the presence of the ionic liquid in organic phase. The stoichiometry of extracted complexes has been determined. The influence of extractant structure, organic diluent nature, and HNO3 concentration in aqueous phase on the efficiency of metal ions extraction into organic phase has been considered.
The specific magnetization and magnetic susceptibility of ferrogarnets of the composition Y3–xCex(Fe0.5Ga0.5)5O12 (x = 0; 0.5) obtained by the gel combustion method have been measured. It has been found that after synthesis and subsequent crystallization at pressure ≈ 10–2 Pa at 1023 K for 2 h, the temperature of magnetic phase transformation in the studied compositions Y3–xCex(Fe0.5Ga0.5)5O12 increases with the replacement of yttrium ions Y3+ by Ce3+. In this case, the effective Curie–Weiss temperature Ɵeff of the antiferromagnetic component of exchange magnetic interactions in Y2.5Сe0.5Fe2.5Ga0.5O12 varies from |–570| to |–650| K.
Lutetium stannate with a pyrochlore structure was synthesized using solid state reaction. The heat capacity of polycrystalline Lu2Sn2O7 in the temperature range of 7.99–1871 K was measured by adiabatic and differential scanning calorimetry methods. Entropy, enthalpy change, and derived Gibbs energy were calculated from the smoothed heat capacity data. The Gibbs free energy of Lutetium stannate from elements was estimated, using the ΔfS°(Т) values obtained in this work and the ΔfH°(Т) values known from the literature. The temperature dependence of the cubic crystal lattice parameter and the value of the coefficient of thermal expansion in the temperature range of 300–1273 K were determined by high-temperature X-ray diffraction.
The microstructure evolution of silver nanowires during their formation by the polyol method at 170°C has been studied. UV-Vis spectrophotometry shows significant changes in the shape of the absorption band associated with the surface plasmon resonance of the resulting silver nanostructures. The X-ray powder diffraction analysis data indicate that all the obtained nanostructures have face-centered cubic lattice of silver. The effect of heat treatment duration on the I(111)/I(200) ratio was studied. The use of scanning electron microscopy has revealed the influence of synthesis conditions on the microstructural features of the particles formed. In particular, after 45 min from the beginning of polyol synthesis a material characterized by an increased concentration of longer nanowires (up to 25 μm in length) is formed, and in individual cases one-dimensional structures up to 70 μm in length are found. The nanowires obtained are characterized by a remarkably short diameter (35–40 nm). The time when the process of silver nanowires destruction is intensified and the concentration of micro-rods and zero-dimensional particles increases has also been determined. It is assumed that individual nanowires in the course of heat treatment of the reaction system are connected by side faces, which leads to their recrystallization resulting in the appearance of one-dimensional structures with a larger diameter and their subsequent degradation because of emerging defects.
A new approach to prepare highly dispersed calcium aluminate at temperatures from 900°C with desired properties (bulk density starting from 0.015 g/cm3, particle size falling in the range of 7–42 nm) is described, which consists of step-by-step heat treatment of a concentrated aqueous solution of Al(NO3)3, Ca(NO3)2, and C6H8O7 in the molar ratio CaO : Al2O3 = 1 : 2. The main stages of the synthesis are studied by X-ray powder diffraction, IR spectroscopy, as well as scanning and transmission electron microscopies. The highly dispersed calcium aluminate obtained using the developed approach has pronounced luminescent properties.
Alloys of the GeTe–Bi2Te3–Te system synthesized by a special technique in a state as close to equilibrium as possible, have been characterized by differential thermal analysis (DTA), powder X-ray diffraction (XRD), and scanning electron microscopy (SEM). An equilibrium solid phase diagram, the liquidus surface projection, selected polythermal sections, and the 300-K isothermal section of the phase diagram have been constructed. The primary crystallization fields of phases, types and coordinates of invariant and monovariant equilibria have been determined. Monovariant equilibria on curves originating from the peritectic points and eutectic point of the GeTe–Bi2Te3 boundary system undergo transformations at certain transition points. A cascade of invariant transition reactions has been identified near the tellurium corner of the concentration triangle, characterizing the joint crystallization of two-phase mixtures of telluride phases and elemental tellurium.
An original combination of thermal activation with exposure to a strong nonuniform electric field transforms a multicomponent solution to a precursor. The transformation of an aerosol into a finished mixture eliminates the stages of gel formation, long-term gel drying, and subsequent contaminating milling, while providing the molecular level of components mixing inherent in the sol–gel method. The phase, chemical, and other thermal manifestations in the bismuth barium borate part (0.2Bi2O3–0.6B2O3–0.2BaO) of the batch, the (Er0.5Y0.5)AG components batch, and the batch precursor, which initially combined all necessary components of glass ceramics, were studied by simultaneous thermal analysis (STA). The Gibbs energy minimization was used to determine the formation conditions of garnet and yttrium borate crystalline phases, identified by X-ray powder diffraction (XRD) in glass ceramic samples formed from ultrafine batches at various temperatures.
Thiosulfate leaching is considered a green gold extraction approach and a gold mine in Laos was subjected to such treatment in this study. A single factor test was undertaken to determine the optimal leaching conditions, leading to the following parameters: thiosulfate concentration of 0.2 mol L–1; copper ion concentration of 0.005 mol L–1; ethylenediamine concentration of 0.01 mol L–1; pH value of 10; leaching time of 4 h; stirring speed of 200 rpm. After leaching, the remaining ion concentrations were relatively low, positively affecting gold recovery. To further enhance the leaching rate, the impact of cetyltriethylammonium bromide (CTAB) on the leaching rate of gold was investigated, revealing that the addition of CTAB can increase gold’s leaching rate while reducing thiosulfate consumption. In conclusion, a comparison was made between thiosulfate and cyanide leaching, where copper-ethylenediamine-thiosulfate leaching exhibited a shorter duration compared to cyanidation, establishing its potential as a more environmentally sustainable approach.
Nitrites and nitrates are commonly used in meat products to extend shelf life, stabilize color, and inhibit microbial growth. However, they can react with amines and amides, forming carcinogenic compounds. Essential oils are being considered as a natural replacement, but their use in the food industry is limited due to instability, volatility, and water insolubility factors. One solution is to encapsulate or interact the oils with other molecules. In this research, we examined the effective role of B12N12 in interacting with terpinen-4-ol and linalool oils as a stabilizer and nanocarrier for their potential application in the food industry, utilizing density functional calculations (DFT) in both gas and water phases. The adsorption energy values and thermodynamic parameters indicated that the oils adsorb onto the B12N12 cage through a chemisorption process. This process is exothermic and involves the formation of a partial covalent bond (B–O) between the cage and the oils. These findings suggest that the B12N12 cage effectively stabilizes and carries the oils. The vibrational frequency and quantum molecular descriptors (QMDs) calculations suggested that the terpinen-4-ol–B12N12 and linalool–B12N12 complexes are stable. Additionally, the solvation energy values, along with notable alterations in the polarity of the complexes, indicated the potential of the B12N12 cage as an effective solubilizer for the oils in water. The analysis using atoms in molecules (AIM) indicated that the interaction between the oils and the cage involves a partial covalent bond. Additionally, molecular electrostatic potential (MEP), Mulliken population analysis (MPA), and UV-Vis spectra for the compounds were computed. The antimicrobial effectiveness of terpinen-4-ol, linalool, terpinen-4-ol–B12N12, and linalool–B12N12 compounds against Escherichia coli (PDB ID: 4WUB) and v (PDB ID: 3VSL) bacteria was investigated using molecular docking techniques. The calculations indicated that terpinen-4-ol and linalool oils demonstrate higher binding affinities in comparison to terpinen-4-ol–B12N12 and linalool–B12N12 compounds when interacting with the 4WUB and 3VSL receptors. The results suggest that terpinen-4-ol and linalool oils, when combined with B12N12, have the potential to serve as natural substitutes for nitrites and nitrates in meat products.
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