APPLICATION OF TITANIUM OXIDE COATINGS FOR NEUTRALIZATION OF HAZARDOUS CHEMICAL SUBSTANCES

Author(s):  
О. Halak ◽  
N. Poltorak ◽  
О. Kravchuk ◽  
V. Synko ◽  
Y. Korol

Contamination of hazardous chemicals is currently considered one of the major environmental problems. The methods of purification of gaseous emissions depending on the physicochemical properties of pollutants, in particular dangerous chemical, their aggregate state, concentration in the gas environment are studied in this article. The effect of aerosol content such as dust and soot is analyzed as well as the efficiency of purification methods at different temperature intervals, methods of purification of multicomponent mixtures. The comparative characteristics of thermochemical, reagent, sorption and catalytic methods are given and the prospects of their application in filtering systems of stationary and mobile objects are evaluated. It has been proved that almost any organic compounds can be oxidized (mineralized) on the TiO2surface. In practice, any photocatalytic air purifier includes a porous TiO2 deposited carrier, which is irradiated with ultraviolet rays and through which air is purged. Photocatalysis is suitable for domestic use as it can occur at room temperature. For example, a thermocatalytic method of destroying harmful substances requires preheating the air to a temperature above 200 ° C. Photocatalysis destroys substances that penetrate even through activated carbon filters. Features of formation of oxide coatings by plasma-electrolytic oxidation of titanium alloys are considered. It is proposed to refine the design of collective defense systems on armored vehicles and stationary facilities with additional installation in the filter-absorber of the grid with the deposited layer of catalytic material, which will neutralize various types of dangerous chemicals due to photocatalytic air purification.

2017 ◽  
Author(s):  
V. A. Borisov ◽  
S. S. Sigaeva ◽  
E. A. Anoshkina ◽  
A. L. Ivanov ◽  
P. V. Litvinov ◽  
...  

2018 ◽  
Vol 72 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Ramesh Babu Nagumothu ◽  
Arunnellaiappan Thangavelu ◽  
Arun Mohan Nair ◽  
Arun Sukumaran ◽  
Tomson Anjilivelil

2019 ◽  
Vol 84 (8) ◽  
pp. 915-923 ◽  
Author(s):  
Stevan Stojadinovic ◽  
Rastko Vasilic

Plasma electrolytic oxidation (PEO) process of Al?Zn?Si alloy in water solution containing 4 g L-1 sodium metasilicate at constant current density of 400 mA cm?2 was investigated. The species present in PEO micro-discharges and their ionization stages were identified using optical emission spectroscopy technique. The obtained PEO spectrum consists of atomic/ionic lines originating from the elements present both in the substrate (Al, Zn) and the electrolyte (Na, O, H). Apart from atomic and ionic lines, AlO band at 484.2 nm was also detected. Plasma electron number density diagnostics was performed from the H? line shape. The electron temperature of 4000?400 K was estimated by measuring the relative line intensities of zinc atomic lines at 481.05 and 636.23 nm. In addition, surface morphology, chemical and phase composition of oxide coatings were investigated by SEM-EDS and XRD. Oxide coating morphology is strongly dependent of PEO time. The elemental components of PEO coatings are Al, Zn, O and Si. The oxide coatings are partly crystallized and mainly composed of gamma phase of Al2O3.


Author(s):  
G Sh Yar-Mukhamedova ◽  
M V Ved’ ◽  
A V Karakurkchi ◽  
N D Sakhnenko

2019 ◽  
Vol 806 ◽  
pp. 70-75
Author(s):  
Marina S. Vasilyeva ◽  
Vladimir S. Rudnev ◽  
Irina V. Lukiyanchuk ◽  
N.E. Zabudskaya ◽  
I.V. Chasovnikov

Sn-containing oxide coatings were prepared via plasma electrolytic oxidation (PEO) of Ti plate in the electrolytes with [SnII-EDTA]2- complex anions or SnO2 particles in the anode and anodic-cathodic modes. The coatings formed in electrolyte with SnO2 particles stabilized by SAS contain SnO2 and Sn0. In the electrolyte with [Sn-EDTA]2- complex anions, the SnO2-containing coatings were formed in the anodic mode while Sn0-containing ones were obtained in the anodic-cathodic mode. SnO2-containing structures formed in the electrolytes with [Sn-EDTA]2- anions are shown to be active in catalytic oxidation of CO into CO2 at temperatures above 350 °C. They can be the basis for the preparation of both carriers of catalytically active compounds and catalysts for redox reactions. Potentiometric tests showed that the Sn-containing PEO layers on titanium exhibit the most characteristic pH function for the metal oxide electrodes in the direct potentiometry and acid-base titration.


2013 ◽  
Vol 78 (5) ◽  
pp. 713-716 ◽  
Author(s):  
Stevan Stojadinovic

In this lecture results of the investigation of plasma electrolytic oxidation (PEO) process on some metals (aluminum, titanium, tantalum, magnesium, and zirconium) were presented. Whole process involves anodizing metals above the dielectric breakdown voltage where numerous micro-discharges are generated continuously over the coating surface. For the characterization of PEO process optical emission spectroscopy and real-time imaging were used. These investigations enabled the determination of electron temperature, electron number density, spatial density of micro-discharges, the active surface covered by micro-discharges, and dimensional distribution of micro-discharges at various stages of PEO process. Special attention was focused on the results of the study of the morphology, chemical, and phase composition of oxide layers obtained by PEO process on aluminum, tantalum, and titanium in electrolytes containing tungsten. Physicochemical methodes: atomic force microscopy (AFM), scanning electron microscopy (SEM-EDS), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and Raman spectroscopy served as tools for examining obtained oxide coatings. Also, the application of the obtained oxide coatings, especially the application of TiO2/WO3 coatings in photocatalysis, were discussed.


CORROSION ◽  
10.5006/0859 ◽  
2013 ◽  
Vol 69 (7) ◽  
pp. 693-702 ◽  
Author(s):  
J.B. Bajat ◽  
R. Vasilić ◽  
S. Stojadinović ◽  
V. Mišković-Stanković

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