Open AccessAPPLICATION OF PLASMA-ELECTROLYTE COATINGS ON TITANIUM WITH REFRACTORY METALS FOR DETOXIFICATION OF ENVIRONMENTS FROM POLLUTING SUBSTANCES
Author(s) -
Мykola Sakhnenko,
Serhii Indykov,
Ann Karakurkchi
Publication year - 2021
Publication title -
vìsnik nacìonalʹnogo tehnìčnogo unìversitetu "hpì". novì rìšennâ v sučasnih tehnologìâh/vestnik nacionalʹnogo tehničeskogo universiteta "hpi". novye rešeniâ v sovremennyh tehnologiâh
Language(s) - English
Resource type - Journals
eISSN - 2413-4295
pISSN - 2079-5459
DOI - 10.20998/2413-4295.2021.01.14
Subject(s) - photocatalysis , titanium dioxide , catalysis , electrolyte , oxide , titanium oxide , titanium , materials science , inorganic chemistry , chemistry , chemical engineering , metallurgy , organic chemistry , electrode , engineering
Based on the review of the peculiarities of the photocatalytic processes, the peculiarities of the catalytic action of oxide systems based on titanium dioxide are determined. It is shown that TiO2 is one of the most chemically and thermally stable and non-toxic inorganic oxides of semiconductors, whose photocatalytic activity is manifested by irradiation with ultraviolet part of the spectrum (λ 320–400 nm) and allows the oxidation of a significant amount of toxic agents to water and carbon dioxide. The essence of the photocatalytic process of oxidation of toxicants under the action of UV radiation on the TiO2 surface is considered. The proposed technology of photocatalytic detoxification of contaminants is economically available, environmentally friendly and allows its widespread use, in particular for autonomous systems, including dual purpose. It is established that the main requirements for materials for photocatalysis are their chemical and biological inertness, photocatalytic stability and activity, low cost. It is shown that the most rational technological form of the photocatalyst is the application (synthesis) of the catalytic layer on structured metal substrates, in particular titanium alloys. It is proved that these catalytic oxide systems can be effectively formed by the method of plasma-electrolyte oxidation in aqueous electrolytes with the addition of dopant metal compounds that increase the photocatalytic activity of the obtained heterooxide systems. It is proposed to use tungsten oxides of variable valence as the target additive. The kinetic regularities of the process of plasma-electrolytic oxidation of titanium VT1-0 in a diphosphate-borate electrolyte with the addition of tungstates have been studied. It is shown that in an electrolyte of this type at a current density of 1.0 A/dm2 in the galvanostatic mode for 30 min a uniform coating of TiO2·WxOy with a tubular torus-like structure and tungsten content of 2.5–7.5 wt.% is formed. The predicted quantitative composition of the heteroxide layer in combination with the surface morphology creates the preconditions for high catalytic activity of the synthesized coating for detoxification of media from anthropogenic pollutants.