Photocatalytic degradation of azo dyes by titanium dioxide supported silver nanoparticles prepared by a green method using Carpobrotus acinaciformis extract

Abstract

In this work, the immobilization of silver nanoparticles (Ag NPs) on the titanium dioxide (TiO2) surface were carried out using Carpobrotus acinaciformis extract as a reducing and stabilizing agent. The modified TiO2 with Ag NPs was characterized by FT-IR spectroscopy, X-ray diffraction (XRD) pattern, field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). The diameter of Ag NPs on the TiO2 was predominantly found within the range 20–50 nm. The photocatalytic degradation of Methyl Orange (MO) and Congo Red (CR) was investigated with Ag/TiO2 nanocomposite as photocatalyst in the presence of two 8 w high-pressure mercury lamps irradiation at room temperature. Complete mineralization was done in these reactions. Photodegradation of dyes was negligible when the reaction was carried out in the absence of the photocatalyst or UV light. The Ag/TiO2 nanocomposite is a highly active and recyclable photocatalyst which can be reused several times without significant losing of its activity in degradation process.