Pulse radiolysis of lodate in aqueous solution

Abstract

The reactions of primary water radiolysis radicals with IO^–₃ have been re-investigated using electron pulse radiolysis and absorption spectroscopy. Rate constants for iodate reaction with e^–_(aq)[(5.45 ± 0.45)× 10⁹ dm³ mol^–1 s^–1], O^˙–[(1.82 ± 0.04)× 10⁹ dm³ mol^–1 s^–1] and ˙OH (< 10⁵ dm³ mol^–1 s^–1) have been measured and compared with previously determined values. The observed iodate concentration dependence of the two transient absorptions produced by its reaction with the hydrated electron and the oxide radical were found to be due only to spur scavenging effects, and thus the dimerization equilibria proposed by previous workers is not necessary. The previously reported rate constants for the reaction of iodate with hydroxyl radicals have been shown to be due to just iodate reaction with the small concentration of O^˙– present in equilibrium with the hydroxyl radical.