Decolorization of high-concentration Reactive Red 2 in water using UV and persulfate in a 3-liter photoreactor

Abstract

This investigation examines the effectiveness of using UV and persulfate (PS) in a 3-liter photoreactor in the decolorization of high-concentration Reactive Red 2 (RR2) in water. At 25 °C, the effects of UV wavelength, UV power, and Na2S2O8 dosage on the decolorization of high-concentration RR2 (100 mg/L) by the UV/PS process were studied. With a UV power of 16 W, the efficiency and rate of decolorization of RR2 in the UV-254 nm/PS process were much larger than those in the UV-365 nm/PS process. The UV-254 nm/PS process with a UV power of 16 W provided a higher efficiency and faster rate of decolorization of RR2 than did the UV-254 nm/PS process with a UV power of 8 W. In the UV-254 nm/PS process (16 W), the efficiency and rate of decolorization of RR2 were enhanced by increasing the Na2S2O8 dosage, suggesting that the decolorization of RR2 was not limited by excess Na2S2O8 dosage. This investigation concerns the sustainable decolorization of high-concentration RR2 (100 mg/L) by the UV-254 nm/PS process in a 3-liter photoreactor. After 60 min, the RR2 (100 mg/L) was completely decolorized and 88% mineralized at 70 °C and an Na2S2O8 dosage of 1.92 g/L in the UV-254 nm/PS process (16 W). Accordingly, the UV-254 nm/PS process in a 3-liter photoreactor at high temperature can be used to decolorize strongly high-concentration RR2 in water.