This research was carried out to study the efficiency of O3/S2O82- system in removal of Reactive Red 120 (RR120) dye sample. Different operating parameter such as pH, initial dye concentration and persulfate dosage were studied to evaluate the performance on removing colour and COD. The removal of colour and COD achieved higher efficiency at pH 7, 100 mg/L of initial dye concentration and persulfate dosage of 5 g S2O82-/1 g RR120. O3/S2O82- with the most effective conditions experienced effective decolourization and degradation of organic pollutants than O3 only. Furthermore, it achieved faster breakdown of azo bond and aromatic groups than O3 after treatment as observed with UV-Vis absorption spectra. The FT-IR analysis obtained new absorption peak that represents alkenes after 20 min of O3 treatment whereas mostly of the absorption bands of O3/S2O82- flattened.
