Dontsova T.A.

The Photocatalysis Mechanism on TiO2 Surface

We discuss the mechanism of heterogeneous photocatalysis (formation of electron-hole pairs) on the TiO2 surface (initiated by ultraviolet radiation) as well as the stage of the photocatalytic process. As a result, we determine that to increase the efficiency of the photocatalytic process in the visible light range it is necessary to reduce the band gap of catalyst based titanium oxide (IV).

The Surface Functionalization of Multiwalled Carbon Nanotubes

The aim of this paper is to develop methods of oxidation of multiwalled carbon nanotubes (MWCNTs) and determine their functional dependence on oxidation conditions. Based on initial MWCNTs we synthesize three series of samples oxidized under different conditions: by concentrated hydrogen peroxide mixed with sulfuric acid under standard conditions, by concentrated hydrogen peroxide mixed with sulfuric acid during boiling, by concentrated nitrate acid at temperatures of 50, 75 and 100 оC.

Structure and Morphology of Zirconium Oxide (IV) Powders Synthesiized by the Thermal Method from Different Precursors

ZrO2 powders were synthesized from different precursors by the thermal method: zirconium hydroxide (ZrO(OH)2) and zirconium oxalate (ZrOC2O4). In synthesized samples by XRD analysis it was researched phase composition; sample, synthesized from ZrO(OH)2, consists of, mainly, the monoclinic modification, and sample, synthesized from ZrOC2O4 – of the tetragonal modification. It was calculated crystal grates parameters of obtained ZrO2 powders by the method of XRS analysis.

Synthesis and Characterization of Nanodispersed Powders of Tin Oxide (IV) from Tin Oxalate (II)

We synthesize powders of tin oxide (IV) from tin (II) oxalate by thermal method with and without chemical pretreatment. The microstructures of samples are investigated by XR-diffraction and microscopic methods of analysis. We establish that the powders obtained by both methods have a tetragonal structure of rutile. It was determined that the sample obtained by chemical method followed by heat treatment, has a more porous structure than the sample obtained by thermal method. The lattice parameters and size of crystallite of the samples are calculated.

Turbidimetry Method of Evaluating the Nanoparticles Sizes in “White Zoles” ZrO2

We determine the possibility of employing turbidimetric method for the express evaluation of particles sizes in “white sols” of zirconium oxide (IV) synthesized by hydrothermal method. We define the phase content in zirconium oxide (IV) synthesized by this method, which mainly comprises the tetragonal modification. We find the particles sizes of zirconium oxide (IV) obtained employing the turbidimetric method, as well as by using the ZetaSizer device. Hence the particles sizes are 62 and 65 nm.

The Interaction of Calcium Phosphate with Oxalate Acid

This paper deals with the experimental research into the effectiveness of utilizing oxalic acid for decomposition of the phosphate component of phosphorites employing the trisubstituted calcium phosphate as a sample. Furthermore, the impact of such parameters as duration, temperature, the stoichiometric ratio of initial reagents is defined in the process of calcium phosphate dissolution. We determine that the calcium phosphate dissolution by the oxalate acid finishes in 30–45 minutes and the temperature at which the maximum expansion of calcium phosphate is 80 C.

Selective leaching of carbonates from ukrainian phosphorites by lactic acid

We select the organic acid for pre-decarbonization of the Ukrainian low-grade phosphate raw material. Through experiments conducted, we determine that lactic acid is the most effective in this process. Wealso demonstrate the infrared spectra of the original phosphate (Ratnovskiy field), as well as of the They indicate that the intensity of stretch vibration, belonging to the carbonate ion of calcite, decreases after treatment with lactic acid phosphate