V. N. Batalova

Catalytic Ozonation of Oxalic Acid Using SrTiO3 Catalyst

A new catalyst, strontium titanate (SrTiO3), has been successfully employed to degrade oxalic acid in catalytic ozonation process. About 4.5%, 9.3% and 45.8% of oxalic acid removal efficiencies were noted in adsorption, ozonation, and catalytic ozonation processes, respectively, which demonstrates the catalytic activity of SrTiO3 towards ozone. The optimum amount of catalyst loading on decomposing oxalic acid was found to be 1.25 g/L. The catalytic stability was investigated up to four successive cycles and found that the catalyst was still stable and efficient.

Catalytic oxidation of phenol in the presence of iron-containing composites based on silicon and boron nitrides

Sorption and catalytic activities of iron-containing composites based on silicon and boron nitrides in purification of aqueous solutions to remove phenol under ozonation and UV irradiation in the presence of oxalic acid and hydrogen peroxide additives was studied.

Analysis of the sorption and catalytic activity of a B-N-Fe composite in water purification to remove oxalic acid

Sorption and catalytic activity of composites based on nitrogenized ferroalloys of boron in purification of aqueous solutions to remove oxalic acid in separate and joint exposure to UV radiation and ozone with and without addition of hydrogen peroxide was studied. The materials were produced by self-propagating high-temperature synthesis. X-ray diffraction analysis and IR spectroscopy were used to determine the presence of hydrated iron oxalate in a composite material upon its contact with a contaminant. The conditions in which the organic contaminant is completely degraded were found.

Metal-ceramic composites prepared under combustion conditions and their catalytic activity in dye degradation

Composites based on boron, silicon, and chromium nitrides and on Sialon were prepared with the aim of using them in photocatalytic degradation of dyes for wastewater treatment. The surface parameters, elemental and phase composition, and morphology and size of particles of the materials were evaluated. The activity of the composites in decolorization of dye solutions under the conditions of generation of photoactive systems (Ruff-Fenton, ferrioxalate, peroxide-ferrioxalate) was studied. The highest degree of dye degradation is reached when using composites based on boron nitride, which is due to the combination of the photoadsorption and photooxidation.

Study of Absorption of Organic Pollutants by Modified Natural Materials

The paper presents the study of the absorption mechanism of organic pollutants such as formaldehyde and oxalic acid by natural zeolite and peat materials modified by iron (III) ions using the limited volume method.The relevance of this paper is a search for the use of inexpensive and available natural sorbents for waste water purification from ecologically hazardous water-soluble organic pollutants. The impact produced by the solution concentration and temperature and the size of natural composite particles on the sorption rate of organic substances is described in this paper. The effective factors for diffusion and energy of the process activation are calculated. It is found that the mixed-diffusion kinetics is the determinant stage of the process. In case of peat and zeolite composites, the internal diffusion prevails in the mixed-diffusion kinetics.

Peat- and Natural Zeolite-Based Solid Composite Modified by Metal Ions for Photodegradation of Dyes in Waters

The present research is aimed at tackling the problem of profound degradation of organic pollutants in waters by creating new composite materials with the given functional properties. The work studies the preparation methods and the catalytic activity of natural peat-and zeolite-based composites during photochemical removal of organic dyes from aqueous media. The composites were prepared by chemical modification with polyvalent metal ions - Fe(II,III), Cu(II), Ce(IV), Ti(IV) – in two ways: ion exchange/saturation and Pechini method (polymerizable complex method). It was shown that the obtained composites are efficient catalysts of oxidative photodegradation of Rhodamine C, Rhodamine 6G, brilliant green and eosine in aqueous solutions.

Use of composites based on boron nitride in combined photocatalytic process for generation of hydrogen and degradation of soluble organic substances

Possibility of using composites based on boron nitride in combined photocatalytic processes for degradation of soluble organic substances and generation of hydrogen was examined. The hydrogen evolution rate and output capacity of the composites under study in release of hydrogen from aqueous solutions of formic and oxalic acids and hydrazine under irradiation with visible and UV light were evaluated. It is shown that the highest efficiency of generation of molecular hydrogen is achieved in photodecomposition of hydrazine and oxalic acid with a composite whose phase composition includes iron and a set of semiconductor carbides (Fe3C, MgC2, Al4C3, SiC).

Synthesis of Nitrogen-Doped ZnS with Camellia Brushfield Yellow Nanostructures for Enhanced Photocatalytic Activity under Visible Light Irradiation

Nitrogen modified zinc sulfide photocatalysts were successfully prepared and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and surface area analysis. Thermal decomposition of the semisolid was carried out under nitrogen conditions at 500°C for 2 hours, and a series of nitrogen-doped ZnS photocatalysts were produced by controlling inflow flow rate of nitrogen at 15–140 mL/min. Optical characterizations of the synthesized N-doping ZnS substantially show the shifted photoabsorption properties from ultraviolet (UV) region to visible light. The band gaps of nitrogen-doped ZnS composite catalysts were calculated to be in the range of 2.58~2.74 eV from the absorptions edge position. The 15N/ZnS catalyst shows the highest photocatalytic activity, which results in 75.7% degradation of Orange II dye in 5 hrs by visible light irradiation, compared with pristine ZnS and higher percentage N-doping ZnS photocatalysts.

Study of sorption and catalytic activity of peat-based composition material in relation to organic pollutants in waters

The effect exerted by modifying iron(III) chloride additive on the sorption and catalytic activity of granulated iron-containing peat composition in removal of oxalic acid was studied depending on the conditions of the solution treatment (ozone, UV radiation, and hydrogen peroxide). The conditions for virtually complete absorption of oxalic acid from model solutions were chosen.