Photo-oxidative Decolorization of Brilliant Blue with AgNPs as an Activator in the Presence of KSO and NaBH.

The decolorization of brilliant blue (E133) in aqueous solution by KSO and NaBH with AgNPs as an activator was studied spectrophotometrically under normal laboratory conditions. Batch experiments were performed to investigate the effects of reaction time, initial dye concentration, activator concentration, solution pH, and temperature on the decolorization of E133. KSO and NaBH did not decolorize the dye E133 in the absence of AgNPs. The optimum dosage of AgNPs was 0.01 g/L, and 98% dye E133 degradation was observed with 3.75 mM KSO at 30 °C in ca. 60 min of reaction time. In the NaBH/AgNPs system, only 60% dye degradation was observed for an identical reaction condition. The decolorization rate constant increases with the increase in concentrations of AgNPs, KSO, NaBH, and reaction temperature. The decolorization degree of the E133 responded linearly with KSO and NaBH concentrations. The existence of sulfate radicals (SO ) and hydroxyl radicals (HO) generated during the decolorization of E133 was identified by using ethanol and tertiary butyl alcohol as scavengers. Based on the E133 solution absorbance changes at 628 nm, the decolorization mechanism was proposed and discussed.