(Digital Presentation) Synthesis and Characterization of Dispersed Zinc Oxide

Abstract

Zinc oxide has the subject of numerous studies in recent years. Nearly half of the world's annual production of zinc oxide is used as an activator to speed up vulcanization in the rubber industry. It is also widely used in pharmaceutical and cosmetic industries. It is most widely used in the chemical industry not only as a starting material, but also as a catalyst and chemisorbent. Recently, zinc oxide has been very often studied as an efficient photocatalyst in advanced oxidation processes. The cheapness and availability of zinc oxide makes it possible to use it also as a white pigment. White pigments make up more than 60% of all modern dyes. They are used for the manufacture of paints and varnishes not only white, but also other colors, as well as in the production of plastics, paper, building materials, ceramics, etc.Obtaining nanodispersed ZnO opens up additional possibilities for controlling its chemical and physical properties. Today, to obtain nanostructured ZnO, chemical deposition, synthesis in colloidal solutions, hydrothermal synthesis, laser vapor deposition, electrochemical deposition, thermal methods, electrochemical deposition, etc. are used. Promising technologies that make it possible to obtain disperse products are physicochemical methods, including those using contact nonequilibrium plasma (CNP).To form nanodispersed ZnO nanoparticles, we used CNP. This method is economically attractive due to the simplicity of the synthesis process (the temperature varies from room temperature to 50°C, the low cost of equipment and consumables) and the possibility of influencing the structural and morphological characteristics of NPs.Theoretical (Pourbaix diagrams) and experimental studies (cyclic voltammograms, potentiometry, kinetic dependences, X-ray phase analysis, derivatography, electron microscopy, spectroscopy) were carried out, which made it possible to establish the possibility of obtaining zinc oxide using CNP and investigate its properties.The results of X-ray diffraction analysis show that under these conditions, a precipitate of ZnO is formed. It was found that with an increase in rarefaction in the plasma-chemical reactor and a decrease in the interelectrode distance, an increase in the degree of conversion of zinc cations into insoluble compounds is observed. To increase the degree of conversion, the effect of organic compounds on the degree of conversion was also investigated. The addition of ethanol in the ratio 50-100 mmol/mol increases the product yield to 99.8% even in dilute solutions. Studies of color characteristics showed that the resulting precipitate has a CRC of 95%, a color purity value of 6%, and a color tone corresponding to a wavelength of 584 nm. The band gap was 3.1 eV.