KINETIC-STUDY OF SO5- AND HO2 RADICALS REACTIVITY IN AQUEOUS-PHASE BISULFITE OXIDATION

A continuous radiolysis has been used for the kinetic study of the rad ical driven bisulfite oxidation in oxygenated and N2O-O-2 saturated so lutions. The initiation rates and initial bisulfite concentrations wer e varied over the ranges (3 x 10(-10))-(3 x 10(-4)) M s(-1) and 10(-4) -(3 x 10(-3)) M, respectively. For oxygenated and N2O-O-2 saturated so lutions the long chain length bisulfite oxidation with the rate determ ining propagation reaction SO5- + HSO3- (k(6)) was observed at low ini tiation rates. The measurement of the peroxydisulfate formation rates has shown that the main termination step in an N2O-O-2 saturated solut ion is the reaction SO5- + SO5- --> S2O82- + O-2 (k(7b)) and in oxygen ated solution is the reaction SO5- + HO2 (k(10)). The rate constants k (6) = (3.6 +/- 0.5) x 10(3) and k(10) = (5 +/- 1) x 10(7) M(-1) s(-1) have been derived. The upper limit of the initiation reaction between of hydroperoxyl radical and bisulfite HO2 + HSO3- has been estimated a s 20 M(-1) s(-1).