Saltpeter negatively affects the human body, it contributes to the formation of a dangerous substance in the blood – methemoglobin, which leads to oxygen starvation. An increase in methemoglobin up to 60% leads to a fatal outcome. Also, the excess of saltpeter in water causes poisoning, disorders of the gastrointestinal tract, excretory and endocrine systems, the destruction of tooth enamel and the appearance of caries. Saltpeter can be determined in water by chemical analysis of the liquid, as well as using nanomaterials. These structures have a sufficiently highly developed adsorption surface, this property helps to detect the presence of saltpeter in water, and at the same time to clean it. The results of the studies made it possible to establish that after passing water with an admixture of saltpeter, the concentration of the latter decreased. Thus, the theoretical calculations showing the possibility of saltpeter adsorption by carbon nanotubes were confirmed. The obtained results and the applied methods can be used in conducting complex high-performance water examinations.

In this paper, we have considered hexagonal double-layered boron and its adsorption properties in particular. The main adsorption characteristics have been elucidated by using the semi-empirical quantum-chemical scheme MNDO. We have investigated both external adsorption and internal infiltration of atoms (H, O, F, Cl) between boron monolayers.

Recently, the search for new materials for nanoelectronics has attracted the interest of scientists. New materials, which are metal-polymer nanocomposites, can be used in modern electronics. The paper presents the possibility and mechanisms for the formation of a metal composite based on single-layer and two-layer pyrolyzed polyacrylonitrile when interacting with silver atoms. The results of the silver atom adsorption on the polymer surface are described, the possibility of filling the interlayer space with metal atoms is shown, and geometric and electron-energy characteristics are established. Theoretical calculations were performed using a molecular cluster model using a non-empirical method in the STO basis. The structure and electron-energy state of a metal-carbon nanocomposite based on pyrolyzed polyacrylonitrile with silver atoms are studied. It was found that the silver atom is adsorbed on the surface of PPAN, and the adsorption process is almost independent of the selected adsorption center. The introduction of metal atoms into the interplanar space of PPAN causes the initially planar monolayers of PPAN to bend, while the structure retains its stability. It was found that the presence of metal atoms in the PPAN structure causes a change in the band gap, which leads to a change in the conductive properties of the resulting nanocomposite.

In various fields of science and technology in recent years, the main objects are nanometer-scale objects. These are fullerenes, carbon nanotubes, nanocomposites, thinfilm multi-layer structures, etc. Nanostructured solids formed from these particles or clusters attract the attention of researchers because they can be used in a wide variety of fields: from science to industry.

Results of modeling and quantum-chemical calculations of metalpolymeric composites on the basis of pirolyzed polyacrylonitrile (PPAN) with metal particles impurities of the threefold Fe-Ni-Co connection are presented in article. The model of single-layer PPAN in which eight atoms of the main substance cluster of polymer are replaced with three atoms of iron, nickel and cobalt is considered. Features of geometrical structure and the electronic and power structure of a nanocomposite are defined. It is established that introduction of a metal nanosystem leads to reduction of width of energy gap of a metalcomposite due to emergence of levels of the replacing metal atoms in a valence band (nickel, cobalt) or on border of a conduction band (iron) that leads to change of the carrying-out properties of the received nanocomposite. On the basis of the analysis of charging redistribution in a system it is established that the charge carriers appearing in a system can participate in the directed movement of free charges in a metalpolymeric composite when imposing electric field that leads to change and magnetic characteristics of a nanocomposite.