Reaction of Sulphate Radical Anion (SO4•-) with Cyanuric Acid: A Potential Reaction for Its Degradation?

A novel reaction between sulfate radical anion (SO4•-) and cyanuric acid (CA), a non-degradable end product of the oxidative degradation of the triazine based herbicide, atrazine, is presented using laser flash photolysis and steady state radiolysis techniques at pH 5. A second order rate constant of 1.9×107 dm3 mol-1 s-1 has been determined and the transient intermediate (λmax=330 nm) is assigned to a radical cation of CA (CA•+). The degradation profile indicated that about 76% of CA have been decomposed after an absorbed γ-radiation dose of 18 kGy. It is therefore proposed that the reaction of SO4•- could be utilised for the degradation of CA in aqueous medium which is normally stable to any Advanced Oxidation Processes.