The photo-oxidative destruction of C.I. Basic Yellow 2 using UV/S2O8 2− process in an annular photoreactor

The photo-oxidative decolorization of C. I. Basic Yellow 2 (BY2), was investigated using UV radiation in the presence of peroxydisulfate (S2O8 2−) in an annular photoreactor at different conditions. S2O8 2− and UV-light showed negligible effect when they were used independently. Removal efficiency of BY2 was sensitive to the operational parameters such as initial concentrations of S2O8 2−, BY2 and pH. The conversion ratios of BY2 at the volumetric flow rates of 330, 500 and 650 mLmin− 1 were 84%, 78%, 69% in 1 h, respectively. The results showed that in the presence of S2O8 2−, the photooxidation quantum yield obtained higher than direct photolysis quantum yield, suggesting that photodecay of BY2 was dominated by photooxidation. The electrical energy per order (EE/O) values for decolorization of BY2 solution was calculated. Results show that applying an optimum peroxydisulfate concentration can reduce the EE/O.