Russian Journal of General Chemistry最新文献

An assessment of the pollution of glacial and non-glacial rivers of the Central Caucasus for the observation period 2020–2024 was conducted. By comparing with established maximum permissible concentrations (MPCs) for NO₂^‒, NO₃^‒, and NH₄⁺, the main pollutants were identified. The content of inorganic nitrogen compounds was determined using chemical analysis methods. Concentration levels of the components in the waters of the following six glacial rivers: the Urukh, Cherek, Baksan, Chegem, Malka, and Terek, as well as in the waters of three non-glacial rivers—Kurkuzhin, Shalushka and Nalchik—are presented. The most polluted watercourses and their flow frequency were established. The results indicate that the range of concentrations of inorganic nitrogen compounds in the waters of glacial-fed rivers varied widely. Interannual and interseasonal variability in their content was noted. The main pollutants in the waters of glacial-fed rivers (NO₂^‒, NH₄⁺) and in the waters of non-glacial origin (NO₂^‒, NO₃^‒, and NH₄⁺) were identified. Generally, there is a tendency for the concentration values of inorganic nitrogen compounds to increase towards the lower reaches of the studied rivers.

This study investigates the chemical structure and U-238 sorption properties of carbon nanomaterials (CNMs) synthesized from tree bark via self-propagating high-temperature synthesis (SHS). The CNM samples were found to be microporous adsorbents with unique characteristics, including high paramagnetic center (PMC) concentrations and biologically active elements such as Ca and Mg. The materials demonstrated effective extraction of trace uranium from aqueous media, supporting their potential development as new enterosorbent agents.

This paper describes a technology tested at the MOSECOMONITORING budgetary institution of the Moscow City Government, which is authorized to conduct state environmental monitoring. The technology is designed to construct three-dimensional pollutant concentration fields using a Gaussian plume model based on MTP-5 temperature profiler data and surface wind measurements. Considering the diurnal variability of temperature stratification in the Moscow metropolitan area, the technology is applied to operational environmental monitoring and source-identification tasks. The feasibility of determining the individual contribution of each air-pollution source is demonstrated. The Gaussian atmospheric-diffusion model is widely accepted and recommended for practical use by international organizations, including the World Meteorological Organization, the World Health Organization, and the International Atomic Energy Agency. A technology for computing backward plumes was also tested to estimate the probable emission area responsible for pollutant concentrations at the monitoring site.

Two series of nanocomposites based on SnO₂ and WO₃ were synthesized by the same route—chemical precipitation of corresponding acids with subsequent thermal decomposition followed by modification with MnO_x via impregnation-annealing technique. Comparative study of phase composition by X-ray diffraction and Raman spectroscopy was carried out. Microstructural parameters (particle size, specific surface area) were determined using electron microscopy and low-temperature N₂ adsorption. Gas sensing properties of the nanocomposites were investigated when detecting inorganic (CO, NO, NH₃) and organic (CH₃OH, C₆H₆) gases.

Atmospheric deposition was studied using poplar (Populus L.) leaves, which were collected from 41 sites uniformly distributed throughout the city of Blagoveshchensk. Unwashed leaves were ashed at 450°C. The ash was analyzed for the content of Ca, Na, Fe, Zn, Sr, Ba, Rb, Co, Cr, As, Th, Sb, Hf, Sc, and U using instrumental neutron activation analysis (INAA). Mercury was determined in dried, unashed leaves using a mercury analyzer. The normalization method was used to compensate for the natural variability of trace elements and identify anthropogenic sources of pollution. Sc was used as the normalizing element. Statistical processing of normalized concentrations included descriptive statistics, cluster, and factor analyses. Pollution assessment through the calculation of the enrichment factor showed that concentrations of most of the studied elements do not differ significantly from the background level. The exception is U, which is characterized as a moderately enriched element. Local emission points were identified. Statistical analysis of normalized data and factor value distribution maps showed that the sources of microelements in poplar leaf ash: vehicle emissions, industrial emissions, and atmospheric dust. This study demonstrates that biomonitoring, combined with statistical data processing, is an effective tool for assessing the state of the ground-level atmosphere.

In this work, terpene-phenolic and terpene-phenol-styrene resins were synthesized using purified crude sulfate turpentine. Their physicochemical characteristics were determined and compared with industrial phenolic resins used in rubber compounds. The softening temperatures and acid numbers of the synthesized resins were comparable to those of commercial analogues, ensuring their compatibility with vulcanization systems. The obtained data confirm the promise of using sulfate turpentine as a renewable raw material for producing resins for the tire industry.

Nitrogen dioxide is one of the most hazardous pollutants in urban air, which underscores the need for reliable monitoring sensors. This work presents a sensing element for NO₂ detection composed of an anisotropic metallic nickel network coated with a thin nickel oxide layer. The temperature dependence of the sensor response was examined over the range 25–180°C, and the response was found to increase progressively with temperature. The influence of humidity on the response becomes negligible at temperatures above 60°C, whereas operating temperatures exceeding 160°C lead to a deterioration in sensor stability. These results define an optimal temperature window that balances high sensitivity, reduced humidity interference, and long-term operational stability. At 140°C, the sensitivity to NO₂ reached 8.3 × 10^–3 ppm^–1. The straightforward fabrication process and the low cost of the materials used make the sensor a promising candidate for modern air-quality monitoring systems.

Microplastic pollution of aquatic environments has become a global environmental problem. The study has found that the freshwater ciliate Paramecium caudatum ingests secondary recycled microplastic particles. Polyvinyl chloride and high-density polyethylene microparticles at concentrations of 5 μg/mL and higher exert a significant negative impact on the survival and behavior of ciliates. Since this organism is an integral part of the planktonic food web, there are certain environmental risks of the advancement of toxic substances along the food chain, which poses a potential hazard to aquatic biota and humans.

The possibility of utilizing organic waste via slow pyrolysis is examined. Sunflower husks and poultry waste were selected as the study subjects. The process of thermal decomposition of the studied biomass and organic waste samples at a heating rate of 10°C/min consists of the stages of drying, devolatilization, and carbonization. Most of the gaseous products were released during the main stage in the temperature range of 270–500°C, which was accompanied by the greatest mass loss. The average residual mass for sunflower husks was 29.6%, while for poultry waste it was 45.5%.

This review presents the latest advances in drug therapy and diagnostics for various diseases, focusing on innovative approaches to address pressing challenges. It explores new methods of drug development and evaluates different delivery systems, including lipid-, polymer-, macrocycle- and metal-based carriers. Special attention is given to various routes of targeted drug delivery, as well as the possibility of delivering DNA and RNA. The review also addresses trends towards preferable use of natural components and personalized medicine. These trends reflect key developments in modern nanomedicine and other related fields.