Kinetics of O�? and O3�? in alkaline aqueous solutions of hydrogen peroxide

Abstract

The photolysis of strong alkaline (pH>12.7) solutions of H2O2 yields O·−, which in the presence of molecular oxygen forms the ozonide radical ion, O3·−. A detailed kinetic study on the reaction mechanisms involved during formation and decay of O3·− radical ions in these solutions, in the presence and absence of added O·−/HO· scavengers is reported. In order to obtain a complete interpretation of the experimental data, kinetic computer simulations were done using a complete set of reactions. A very good agreement between experimental and computer simulated data is obtained. The following simplified mechanism accounts for the observed first-order decay of O3·− in alkaline hydrogen peroxide solutions: O·− + O2 → O3·− O3·− → O·− + O2 O·− + S → OH· + S → HO· + HO2− → O2·− + H2O O·− + HO2− → O2·− + HO− with S: O·−/HO· scavengers. © 1997 John Wiley & Sons, Inc.