“…has been studied. [4][5][6] Peroxymonosulfate (HSO5 -), peroxydisulfate (S2O8 2-), or persulfate ( SO4 -) were used to generate reactive radicals in the presence of activators which can be heterogeneous or heterogeneous catalysts of transition metals (Cu, Co, Fe, and Mn), UV irradiation, carbon-based catalysts, ultrasound irradiation, microwave, heat and electrochemical processes. [1] Meanwhile, the application of hydroxyl radicals is due to the strong oxidation capacity of free radicals formed in-situ such as OH, O2 -, HO2 , etc.…”