Formation of hydrated electron and BrO3 radical from laser photolysis of BrO3- aqueous solution
Abstract
Hydrated electron, as well as BrO3 radical, was observed as one of the products from the laser photolysis of bromate (BrO3-) aqueous solution, with an initial quantum yield of (8.0±0.8)×10-2 determined. The hydrated electron produced can be scavenged rapidly by O2, OH radical and the parent compound BrO3-. The rate constant for the reaction of eaq- with BrO3- was determined to be 3.0×109 d mol-1 s-1 at ionic strength I=0. The BrO3 radical was observed to have an absorption peak at 315 nm with a molar absorption coefficient of ∽8×102 d mol-1 cm-1. In addition, BrO3 could be also produced from the electron transfer reaction of the sulfate radical (SO4-) with BrO3-. The radical prefers to dissociate rapidly to form the BrO radical (at a rate of >2.0×105 s-1). It was also suggested that some of the BrO came from direct photolysis of BrO3- solution. Quantum yields of BrO2 and O from the photolysis of BrO3- were determined to be 0.12±0.01 and (7.4±0.6)×10-3, respectively.