The ZnO-SnO₂-Fe₂O₃ composites containing flower-like particles were prepared by the non-isothermal polymer-salt method. Thermochemical processes proceeding during composites synthesis was studied by DTA/TG method. The structure and morphology of obtained composites were studied by the SEM and XRD analysis. Prepared composites containing small amounts of SnO₂ and Fe₂O₃ demonstrate the high adsorption and photodecomposition of the organic dye Rhodamine 6G in its solutions. Obtained materials show the ability of the photogeneration of the chemically active singlet oxygen under the visible irradiation. The synergistic effect of the flower structure and Fe₂O₃ doping can significantly improve the photocatalytic and adsorption activities.

The synthesis of ZnO-MgO nanocomposite via modified Pechini method was performed. The crystalline structure and the morphology of nanocrystals were studied by X-ray diffraction analysis and scanning electron microscopy. The study on the kinetics of diazo dye adsorption and its photocatalytic decomposition on the surface of nanocomposite was performed. It was shown that the rate of adsorption process in aqueous solution is described by a kinetic equation of the first order. The application of the nanocomposite allows to significantly increase the efficiency of UV water treatment and its purification from the dye. However, a brief deviation of experimental data on the rate of photocatalytic degradation from the values of the widely used kinetic equation of the first order is observed. Keywords: photocatalysis, adsorption, ZnO-MgO, nanocomposite, kinetics.

The impurity composition of multi-sector plates of nitrogen and boron-containing synthetic HPHT diamonds has been investigated by laser-induced breakdown spectroscopy. It is shown that a comparative analysis of the intensities of the characteristic atomic and molecular bands in the plasma emission spectrum during laser-induced modification of the surface of the samples makes it possible to distinguish both the type of diamond and the crystallographic orientation of the analyzed sector of the sample.