Parameters of underwater plasma as a factor determining the structure of oxides (Al, Cu, and Fe)

Abstract

Nanostructured metal oxides are of great interest because of their unique properties. Plasma in contact with a liquid is a promising method for the synthesis of metal oxides. The synthesis conditions affect the characteristics of the resulting substances. This report presents the results of studies of the effect of plasma parameters on the structure and properties of metal oxides (Al, Cu, Fe), which are formed in the plasma zone. Experiments were carried out at two discharge currents of 0.25 A and 0.8 A. The resulting powders were characterized by different methods of analysis. For copper electrodes, a change in plasma parameters does not lead to a change in composition (mixture of copper oxides). In the case of Al, at a low discharge current, γ-Al2O3 is formed, and at a high current, γ-AlOOH is formed. For iron electrodes, at 0.25 A, a mixture of FeO + Fe3O4 is formed, and at 0.8 A, a mixture of polymorphic modifications of Fe2O3 is formed. The resulting oxide structures were studied as a sorbent for removing chromium ions. The removal efficiency decreases from 89% to 30% for oxide structures obtained at 0.25 A and 0.8 A, respectively.