Photo-oxidation process of indole in aqueous solution with ZnO Catalyst: Study and optimization

Abstract

The photo-oxidation of indole has been investigated using the catalytically active ZnO in aqueous solution, under various physical and chemical conditions. First of all, a structural analysis with X ray diffraction (XRD) shows that ZnO powder crystallizes in wurtzite with a main grain size estimated to be about 270 nm. An increase in catalyst loading greatly enhances the process efficiency until a certain. limit. Indole photodegradation improves with increasing air flow. The effect of the pH on the photo-oxidation efficiency was carried out from 3.88 to 11.16. The activity exhibits its maximal value around the natural pH (6.68). Photocatalytic degradation showed that the activity of ZnO improved with increasing light intensity. This was ascribed to the fact that there was a more efficient generation of electron-hole pairs used in the degradation process.