Decolorization of textile azo dye reactive orange 16 with UV/H2O2 process

Abstract

The photochemical decolorization of C.I. Reactive Orange 16 (RO16), a reactive textile azo dye by the UV/H2O2 process using a batch photoreactor with UV lamps emitting at 253.7 nm, was studied. Complete decolorization of 50.0 mg dm-3 initial dye concentration was achieved in less than 6 min under optimal conditions (25 mM initial peroxide concentration, at pH 7.0 and with UV light intensity 1950 ?W cm-2). The effect of experimental variables, such as initial pH, initial concentration of H2O2, initial dye concentration, and the intensity of UV light was studied. The highest decolorization rates were performed at peroxide concentration in range from 20 mM up to 40 mM, above which decolorization was inhibited by a scavenging effect of peroxide. The decolorization was more efficient in neutral pHs. The efficiency of the process was improved in lower initial dye concentration and at higher intensity of UV light.