Decolorization of azo dye Orange G by aluminum powder enhanced by ultrasonic irradiation

In this work, the decolorization of azo dye Orange G (OG) in aqueous solution by aluminum powder enhanced by ultrasonic irradiation (AlP-UI) was investigated. The effects of various operating operational parameters such as the initial pH, initial OG concentration, AlP dosage, ultrasound power and added hydrogen peroxide (H2O2) concentration were studied. The results showed that the decolorization rate was enhanced when the aqueous OG was irradiated simultaneously by ultrasound in the AlP-acid systems. The decolorization rate decreased with the increase of both initial pH values of 2.0-4.0 and OG initial concentrations of 10-80 mg/L, increased with the ultrasound power enhancing from 500 to 900 W. An optimum value was reached at 2.0 g/L of the AIP dosage in the range of 0.5-2.5 g/L. The decolorization rate enhanced significantly by the addition of hydrogen peroxide in the range of 10-100 mM to Alp-UI system reached an optimum value of 0.1491 min(-1). The decolorization of OG appears to involve primarily oxidative steps, the cleavage of N=N bond, which were verificated by the intermediate products of OG under the optimal tested degradation system, aniline and 1-amino-2-naphthol-6,8-disulfonate detected by the LC-MS. (C) 2014 Elsevier B.V. All rights reserved.