Modeling Control over the Size and Phase Composition of Submicron Particles of Titanium Dioxide Synthesized in a Flow Pl
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ling Control over the Size and Phase Composition of Submicron Particles of Titanium Dioxide Synthesized in a Flow Plasma-Chemical Reactor S. M. Aulchenkoa, * and E. V. Kartaeva aKhristianovich
Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia *e-mail: [email protected] Received November 16, 2016; revised September 20, 2019; accepted February 14, 2020
Abstract—A mathematical and experimental modeling of the process of synthesis under nonequilibrium conditions of a fine powder of titanium dioxide anatase crystalline modification with a combination of reaction zones and counter hardening has been carried out. The formation of ultrafine particles occurs in regions with large values of the convective derivative of temperature (~105 K/s). The mass-average particle size was 10– 70 nm in calculations and 32–45 nm in experiments. The anatase content of the powder in calculations was 70–90% and in experiments ~83%. This method allows control over the phase composition and particle size of the synthesized titanium dioxide powder used as photocatalysts, in particular, when treating wastewater from organic waste and air from harmful impurities. Keywords: titanium dioxide, plasma chemical reactor, mathematical modeling, experiment DOI: 10.1134/S0040579520040144
INTRODUCTION The plasma chemistry of submicron powder materials and coatings is an intensively developed area. Although the industrial application of this method has been mastered for a long time, both theoretical and experimental studies of the mechanisms of nucleation and growth of nanocrystalline titanium dioxide particles in the course of their synthesis are ongoing [1–3]. Synthesis-process control issues have been studied to a lesser extent. The results of mathematically modeling the process of synthesizing submicron particles of titanium dioxide in a flow plasmachemical reactor for some modes of its operation is presented in [4, 5]. These modes differ in the flow rate and the gas composition of the plasma-forming jet and the reactant jets. The flow rate and location of the quenching jet also differed. In [6, 7], for some modes, the results of experimental and theoretical studies of the synthesis of submicron particles of titanium dioxide are presented, allowing us to conclude the adequacy of the physicochemical and mathematical models used for the real conversion process taking place in the reactor. Parameters that affect the size and phase composition of particles that can be used as control parameters were identified. The anatase form of titanium oxide is widely used in various sectors of the economy. It has a high specific
surface area and adsorption volume, which determines the use of anatase for the production of sorbents, catalysts, and catalyst supports. Obtaining anatase is a difficult task, which is currently being solved using multistage technologies for the deposition of hydrated titanium dioxide or the hydrolysis of specially prepared solutions of titanyl sulfate purified from impurities and
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