Degradation of acetic acid with sulfate radical generated by persulfate ions photolysis

The photolysis of S2O82- was studied for the removal of acetic acid in aqueous solution and compared with the H2O2/UV system. The SO4- radicals generated from the UV irradiation of S2O82- ions yield a greater mineralization of acetic acid than the OH radicals. Acetic acid is oxidized by SO4- radicals without significant formation of intermediate by-products. Increasing system pH results in the formation of OH radicals from SO4- radicals. Maximum acetic acid degradation occurred at pH 5. The results suggest that above this pH, competitive reactions with the carbon mineralized inhibit the reaction of the solute with SO4- and also OH radicals. Scavenging effects of two naturally occurring ions were tested; in contrast to HCO3- ions, the presence of Cl− ions enhances the efficiency of the S2O82-/UV process towards the acetate removal. It is attributed to the formation of the Cl radical and its great reactivity towards acetate.