Solid phase oxidation of arsenite and the effect of gamma radiation

The oxidation of solid arsenite by bromate, chlorate and perchlorate ions has been studied at different temperatures and at a constant composition of 12. Arsenite is completely oxidized to arsenate. The fraction oxidized // — time /t/ data are reproducible. The rate of oxidation increases with an increase in temperature. Gamma radiation has no significant effect on the temperature independence of the oxidation process of this particular composition, although delayed oxidation appears with irradiated systems. The kinetics of oxidation process follows the conventional first order. The activation energies for the oxidation of As/III/ to As/V/ are 30.5, 44.0 and 67.9 kJ mol^–1, respectively, for bromate, chlorate and perchlorate systems, and for irradiated 29.8 and 67.3 kJ mol^–1, respectively, for bromate and perchlorate systems.