Oxidation of diatrizoate in aqueous phase by advanced oxidation processes based on solar radiation

•Direct photolysis by solar irradiation shows a low effectiveness in DTZ degradation.•The solar radiation/K2S2O8 system yields low percentage degradation.•Processes with iron salts permit total DTZ degradation.•DTZ degradation products were detected for each process.•Degradation byproducts are more toxic than the baseline product.