FUNCTIONAL SILOXANES - NEW APPROACHES TO SYNTHESIS AND PROSPECTS FOR THEIR APPLICATION

Работа выполнена при финансовой поддержке РНФ, проект № 22-13-00459

Quantification and Speciation of Trace Metals under Pollution Impact: Case Study of a Subarctic Lake

Monitoring the quantity and quality of metals in lake water is a major part of assessing water toxicity. A fundamental aspect of geochemical monitoring studies is the evaluation of the equilibrium distribution of metal speciation in water and the influence of environmental conditions on this process. It is important to understand the difference between the behavior of nanoparticles, dissolved particles, colloid particles, and suspended particles. This study involved environmental aquatic chemistry research and the assessment of the geochemical processes of metal speciation in an arctic lake in the metallurgical waste zone and other areas where natural processes prevail. Consecutive and parallel membrane filtration methods were used to compare the results of water analysis in Imandra Lake. The membrane pore sizes were 8, 1.2, 0.45, and 0.2 µm. The following filtrate characteristics were used: microfiltration-based mechanical suspension and oxidized contaminants (>8, 1.2, 0.45, 0.2, 0.1 μm), and ultrafiltration-based colloids, bacteria, viruses, etc. (less than 0.1 μm). Industrial effluents led to the formation of higher concentrations of elements (Ni, Cu, and Pb) in their labile forms. In the wastewater-mixing zone, the concentrations of most elements were evenly distributed in depth. In more distant areas, we found a significant increase in the concentration of elements in the near-bottom horizon in comparison with the surface water (Fe by more than three times). The obtained results showed that numerous elements had diverse distributions by speciation in the points located closer to the source of wastewater. This indicated the significant influence of the adsorption process on the system balance of elements such as Fe, Cu, and rare earth elements. The impact of the regional geochemical and anthropogenic speciation and the possible influence of climatic factors on the distribution of speciation were determined

Geochemistry and radionuclide content of sediment and water samples obtained from the Ob and Irtysh river, Russia

This paper reports the results of the investigations of 2006-2007 on the distribution and migration forms of artificial radionuclides and chemical elements in the Ob-Irtysh water system. Three regions were studied. One of them is a local segment of the Ob River upstream from the confluence with the Irtysh River; its investigation allowed us to estimate the general radioecological state of the aquatic environment affected by the activity of the Tomsk 7 plant. The second region is a local segment of the Irtysh River upstream from its confluence with the Ob River, where the influence of emissions from the NPO Mayak could be estimated. The third region is the water area of the Ob River after its confluence with the Irtysh River. It characterizes the real level of radioactive and chemical contamination of the middle reaches of the Ob River. In order to explain horizontal variations in the distribution of radionuclides in the upper layer of bottom sediments collected at various sites, the results of sorption-kinetic experiments with radioactive tracers in the precipitate-solution system were used. The investigation of the migration forms of trace elements and radionuclides occurring in river water was based on the method of tangential-flow membrane filtration. Chemical element contents were determined in 400-ml water samples. A set of Millipore polysulfone membranes with pore sizes of 8, 1.2, 0.45, 0.1, and 0.025 µm was employed. Taking into account the ultralow specific concentrations of radionuclides in the water, they were analyzed in 300-500 litre samples using Millipore polysulfone membranes with pore sizes of 0.45 µm and 15 kDa. This allowed us to estimate the percentages of cesium-137 and plutonium-239, 240 in the suspended particulate fraction, colloids, and dissolved species

Methodical aspects of studying distributions of chemical elements between soil the micro and nanoparticles

Рассмотрены методические аспекты выделения, фракционирования и определения химического состава почвенных микро- и наночастиц. Приведены примеры использования электронной микроскопии для изучения почвенных коллоидов, микро- и наночастиц. Даны результаты определения содержания химических элементов масс-спектральным методом с индуктивно-связанной плазмой и органических компонентов в водных почвенных вытяжках, полученных после мембранной фильтрации с размером пор 8, 1,2 мкм и 100 kD для иллювиально-железистых подзолистых почв. Методами вольтамперометрии определены ионы меди, свинца, кадмия, цинка в вытяжках после мембранной фильтрации и сопоставлены с содержанием органического вещества с высокой и низкой молекулярной массой. Проанализированы структурные особенности гумусовых веществ в образцах по фотографиям, полученным с помощью электронного микроскопа. Рассмотрено изменение количественных и качественных особенностей гумусовых соединений в слоях почв и различия в формах нахождения металлов в пробах.Considered methodological aspects separation, fractionation and chemical analysis of soil micro-and nanoparticles. Presented the examples of use of electron microscopy to study the soil colloids, micro- and nanoparticles. Shows the results of determination of chemical elements mass spectral analysiswith inductivelycoupled plasmaand organic compoundsin aqueoussoil extractsobtained after membrane filtration with a pore size of 8,1.2 micronsand 100 kD forilluvial-ferruginous podzolic soils. Voltammetric methods identified ions of copper, lead, cadmium and zinc in the extracts after membrane filtration and compared with the content of organic matter with a high and low molecular weight. Analyzed the structural characteristics of humic substances in the samples from the photographs obtained with an electron microscope. The change in the quantitative and qualitative features of humic compounds in soil layers and finding the differences in the forms of metals in the samples