Moscow University Chemistry Bulletin最新文献

This paper describes a method for plasma processing of ash obtained after the incineration of sewage sludge, based on the complete melting of the ash followed by its rapid cooling. The chemical composition of the vitrified slag formed as a result of plasma treatment is analyzed. It is noted that leaching with preliminary activation by grinding substantially decreases the concentration of metal oxides in the slag, which is an effective way to protect the environment.

Rapid advancement of nanotechnology and the increasing demand for nanomaterials (including those of metal oxide nanoparticles (NPs)) require the development of cost-effective and environmentally friendly synthesis methods. Green chemistry and its synthesis methods are an effective solution to this challenge. They enable the production of metal oxide NPs of various compositions, structures, and sizes with minimal environmental impact. Diverse green synthesis methods and reagents allow for the selection of the most cost-effective options for various regions. Modern green chemistry methods to produce and stabilize metal oxide NPs of copper, zinc, zirconium, iron, and titanium are considered in this review. Their advantages, disadvantages, and potential future developments are discussed. The properties and practical applications of metal oxide NPs obtained with green chemistry methods are also described.

An elemental analysis of a thyme herb (Thymus serpyllum L.) that grows in the Chuvash Republic (Russia) is performed for the first time in this study with an X-ray fluorescence method. In the analyzed samples, among the 22 detected chemical elements, higher contents are found for potassium, calcium, phosphorus, silicon, and iron. The macroelements can be arranged in the following order (in mg/kg): K (12 410) > Ca (8960) > P (6000) > S (1480) > Cl (1280). The content of microelements in the thyme herb samples is as follows: Si (7590) > Fe (350) > Mn (80) > Zn (30) > Sr (20) > Cu, Br (10). Titanium (40 mg/kg), rubidium, and chromium (10 mg/kg each) are found in the samples. Toxic elements (cadmium, lead, mercury, and arsenic), as well as silver, zirconium, and vanadium, are not detected in the samples. The elemental composition of Chuvash thyme is compared with samples from the Goris Region (Armenia) and medicinal plant materials manufactured by Fitofarm (Anapa, Russia) and Zdorovye (Moscow oblast, Russia). The absence of heavy toxic metals and arsenic together with the rich macro- and microelement composition of Chuvash thyme make it suitable to produce various preparations used in traditional and folk medicine, cosmetology, perfumery, cooking, and other industries.

In this study, silver nanoparticles are synthesized using aqueous extracts of Matricaria chamomilla and Calendula officinalis flowers. The composition of the precursors, size, and morphology of the silver particles are determined using IR and UV spectroscopy, dynamic light scattering, and transmission electron microscopy. The resulting silver nanoparticle solutions are found to be active against E. coli and S. aureus.

This article studies the development of a simple chromatographic analysis to determine the low concentration of sucralose in combined sweeteners. Using hydrophilic interaction liquid chromatography (HILIC) with a complex-forming sorbent based on silica gel modified with immobilized 2-hydroxyethyliminodiacetic acid (HEIDA) groups saturated with La³⁺, it is shown that low concentrations of sucralose can be determined in the presence of a 1000-fold excess of erythritol, due to its relative enrichment in acetonitrile. The best separation of sucralose and erythritol is achieved using a mixture of acetonitrile and water (95 : 5 vol %) as the mobile phase. The developed procedure for determining sucralose by HILIC using a refractometric detector is used to determine it in samples of erythritol-based combined sweeteners. The detection limit for sucralose is 28 μg/mL.

Self-organization, specific electrical conductivity, UV absorption spectra, and fluorescence of aqueous solutions of ethyl alcohol with a concentration of 100 to 1 vol % are studied. It is shown that as the alcohol concentration decreases structural rearrangements, accompanied by nonmonotonic changes in the nature, size of the formed particles, and their percentage content, occur in solutions. It is found that structures with a size of hundreds of nm and a negative ζ-potential (domains) reach the highest content in the range of 60–30 vol % alcohol. In this range of alcohol concentrations, a relationship between the nonmonotonic concentration changes in the size of domains, their ζ-potential, specific electrical conductivity, and fluorescence intensity (I₃₄₀) is established, indicating that water–alcohol solutions behave as self-organized dispersed systems.

A test system for determining the dissolved oxygen content in water in the range of 0 to 14 mg/L is developed which consists of a tablet, an ampule, and an indicator scale. Testing is carried out on eight water bodies in the Yadrinsky District of the Chuvash Republic: the Sura, Vyla, Arbashka, and Mochkaushka rivers; Sergach and Round Pit lakes; and Mirsky Pond. Samples were taken in June, 2024 in accordance with GOST (State Standard) 59024-2020. The reliability of the results is confirmed by the Winkler iodometric titration method. It is found that the dissolved oxygen content in the water samples from the considered reservoirs is at a level of at least 6 mg/L, which corresponds to the norms of RD (Regulatory Document) 52.24.419-2019 for fishery facilities in the summer season.

In the present paper, we report results from liquid–liquid extraction-spectrophotometric studies on two different systems, each containing W(VI), a 2-hydroxy-5-chlorothiophenol (H₂L), and aminophenols (AP_1,2), namely, 2(N,N-dimethylaminomethyl)-4-chlorphenol (АP₁) and 2(N,N-dimethylaminomethyl)-4-bromphenol (AP₂)}. Extraction of mixed-ligand complexes is maximal at pH 4.1–5.2. The absorption maxima of the mixed-ligand complexes (MLCs) W(V)–L–AP_1,2 lie in the range of 476–480 nm. The molar absorption coefficients are (2.3–2.4) × 10⁴. The proposed method were applied to the determination of tungsten in steel and soil samples.

The interaction between hydrogen and AB5 alloys, intended for their use under arctic conditions, is studied. The thermodynamic parameters of hydrogen absorption and desorption reactions are found, and the influence of alloying with manganese and aluminum on them is studied. The experimental data are compared with those calculated with a statistical forecast model.

A simple and cheap method for the simultaneous determination of two dyes by digital image colorimetry using a smartphone camera is developed. A prototype of a specialized box that allows reducing the contribution of scattered radiation to the measured signal to the noise level of the digital image sensor is created. The proposed approach is tested in determining synthetic food dyes in carbonated beverages. The accuracy of the results of determining dyes in beverages by digital image colorimetry and spectrophotometry differs insignificantly.