No abstract

The photocatalytic and physicochemical properties of titanium (IV) oxide modified by yttrium and niobium oxides were studied. It is shown that modification is a powerful way to increase the efficiency of catalysts' photocatalytic properties and improve the photocatalytic process as a whole. Commercial and laboratory-synthesized titanium (IV) oxides were used as catalysts for modification. Modification of titanium (IV) oxide powders in an amount of 1 wt. % by appropriate modifiers was performed by the hydrothermal method, after which they were characterized by diffraction and X-ray fluorescence methods. The structural characteristics of modified and non-modified titanium (IV) oxide samples by the method of low-temperature nitrogen adsorption-desorption have been studied. A slight increase in the specific surface area was found: from 61 m2/g to 70 m2/g for the commercial sample and from 172 m2/g to 180 m2/g for the synthesized one in this work. Similar dependencies are observed when studying the optical properties by the spectrophotometric method. Determination of surface properties (surface acidity) of modified and non-modified photocatalysts based on TiO2 showed different effects of modifiers on TiO2 acidity: in the modification by yttrium oxide, the acidity decreases, and in the case of niobium oxide – increases. Studies of photocatalytic and sorption activities with respect to dyes of different nature are not the same – the photocatalytic activity after modification increases, the sorption capacity with the cationic dye decreases, anionic – increases. Additional studies on dye destruction are in full accordance with photocatalytic and sorption experiments.

No abstract

No abstract

Membrane technologies have become widely used in filtration and separation processes in chemical, oil, food, pharmaceutical, medical, environmental, textile industries, etc. Recently, there is a growing demand for the use of bactericidal membranes due to their effectiveness in neutralizing microorganisms. The aim of this work is to synthesize microfiltration ceramic membranes modified with silver nanoparticles to provide them with bactericidal properties. In this work, ceramic membranes are synthesized by dry pressing followed by sintering from natural raw materials of Ukrainian origin, namely: kaolin and saponite, as well as with the addition of silicon carbide, sodium silicate, and calcium carbonate. To provide ceramic membranes with bactericidal properties, they were modified with particles of silver. The synthesized ceramic membranes were characterized by X-ray diffraction and fluorescence analysis, and their bactericidal ability has been established. The ceramic filtration membranes after modification by silvers exhibited an inhibitory effect on the growth of Gram-positive (B. subtilis.) and Gram-negative (Escherichia coli) pathogens. Thus, the obtained bactericidal ceramic membranes are of great interest for their use for biofouling control.