The oxidation of Cu(I) by oxygen gas in concentrated NaCl solutions: A kinetic study

Abstract

The oxidation of Cu(I) by oxygen gas in concentrated NaCl solutions was studied in a standard stirred reactor. Each test was carried out at constant pH and under stable hydrodynamic conditions. The effect of stirring speed, solution volume, temperature, pH, oxygen partial pressure, chloride and copper ion concentration of the solution were evaluated. The oxidation of Cu(I) followed linear kinetics up to 85% of the copper ions in the cupric state. The experimental results were interpreted by using the film theory of mass transfer with chemical reaction. In the linear range, the chemical reaction was found to be first order with respect to oxygen concentration. The kinetic constant is given. The flux equation was specific of a fast reaction regime and the overall reaction rate was independent of the mass transfer coefficient k L up to a k L -value of about 10 −2 cm/sec. A parallel study of the oxidation of SO 3 2− by oxygen gas was carried out in the same reactor. The effects of stirring speed and solution volume were similar for both systems.