The rapid development of medicine has forced equally rapid progress in the field of pharmaceuticals. In connection with the expensive and time-consuming process of finding new drugs, great emphasis is put on the design and use of metal and metal oxides nanoparticles in nanomedicine. The main focus is on comprehensive presentation of both physicochemical properties and the possibilities of using, in particular, silver (Ag) and gold (Au) nanoparticles, as well as zinc oxide (ZnO) and titanium oxide (TiO2) nanoparticles as drug carriers and in the treatment of cancer. An important element of this subject is the possibility of occurrence of toxic effects of these nanoparticles. For this reason, possible mechanisms of toxic actions are presented, as well as methods used to reduce their toxicity to ensure the safety of drug carriers based on these nanostructures.

Multifunctional materials have become an important research subject in recent years. Zinc oxide nanoparticles (ZnO NP) deposited on iron oxide (Fe 3 O 4) allow to obtain material with photocatalytic and magnetic properties. The mass share of Fe 3 O 4 in the composite was 30%. Saturation magnetization for this sample was about 9.5 emu/g. The use of magnetic material allows to recover the photocatalyst after the photodegradation process and reuse it. The possibility of recovery of Fe 3 O 4 nanoparticles with a magnet was estimated at 94.80%, while the recovery of Fe 3 O 4 /ZnO achieved 83.91%. The effects of the type of dyes (Methylene Blue, Methyl Orange, Quinoline Yellow, Eriochromic Black T and Trypanic Blue) on their photodegradation efficiency in terms of molar mass of the dye, the solvent in which the processes were carried out and the type of dye charge were investigated. The photocatalytic material showed higher photodegradation activity of dyes while increasing their molar mass. ZnO NPs deposited on Fe 3 O 4 presented 95.61% photocatalytic efficiency against Trypan Blue and 63.02% against Methylene Blue. Increasing the surface area of the catalyst to 39 m 2 /g and the presence of micro-, meso-and macropores had a positive effect on the sorption process of dyes, especially those of larger sizes, allowing their degradation in the photodegradation process.

ZrO 2-ZnO nanoparticles with different mass concentrations of ZrO 2 (1%, 5%, 10%, 20%) were prepared using a two-stage precipitation method with microwave irradiation. The ZrO 2-ZnO with 10% of ZrO 2 had the highest photocatalytic activity. The obtained material was characterised using XRD, which confirmed a high crystal structure in the synthesised material, and transmission electron microscopy (TEM) analysis, which depicted that micro and nano needle-shaped particles had been obtained and that irregularly shaped nanoparticles were present on the surface of those particles. TEM-EDX analysis confirmed the presence of both ZnO and ZrO 2 in the product. FT-IR analyses showed that the positions of peaks related to Zn-O and Zr-O absorption bands did not change in ZrO 2-ZnO NPs. The initial concentration of Methylene Blue (MB), the pH of the solution, and the mass of the photocatalyst were investigated to determine the photocatalytic efficiency of the material and the degree of removal of the MB. The highest efficiency (97%) was obtained in the following conditions: 30 mg/ dm 3 of the MB solution, pH 9 and 70 mg ZrO 2-ZnO after 30 min of reaction time under UV irradiation.

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This paper presents a method for removing organic dyes by sorption and photocatalytic processes on a bentonite bed modified with ZnO-CuO nanocomposite. The effect of the initial dye concentration and temperature on the amount of dye removed from the solution was investigated. The results obtained at equilibrium state allowed us to determine the equilibrium and kinetic models and the thermodynamic parameters for the studied processes. The Langmuir isotherm is the best model for describing the equilibrium processes for both sorption and sorption with photocatalysis. In terms of kinetics, both processes are accurately described by the pseudosecond order model, which demonstrates the chemical nature of sorption. Due to the negative ΔG values calculated from the tests, it was found that the studied processes are spontaneous. It was possible to obtain a better degree of purification of the dye solution using combined sorption and photocatalysis compared to the sorption process itself.