UV irradiation catalyzed persulfate advanced oxidation process for decolorization of Acid Blue 113 wastewater

A UV/persulfate advanced oxidation process was proposed to decolorize and mineralize a synthesized Acid Blue 113 (AB113) dyeing wastewater. Various operating parameters which affected the removal efficiencies of dye and total organic carbon (TOC) such as reaction time, persulfate dosage, initial dye concentration, initial pH, and UV intensity were studied. Results presented effective removal of AB113 azo dye by UV/persulfate process based on both color and TOC indicators. However, reaction with either UV irradiation alone or persulfate alone can reach low-removal efficiency of AB113. In UV/persulfate process, the higher the persulfate dosage applied, the higher the color and TOC removal efficiencies can be obtained up to 6.3mM persulfate concentration. The color removal efficiency and reaction rate constant decreased with increase in the initial dye concentration. The initial pH was shown no significant effect on removal efficiency. UV intensity affected AB113 removal efficiency significantly when the persulfate dosage was as low as 1.05 mM. Results of UV-Visible spectrophotometry indicated the diminishing of chromophore group of AB113 at 566nm and naphthalene rings at 272 nm.