Biosynthesis of ZnO nanoparticles supported on bentonite and the evaluation of its photocatalytic activity

Abstract

This study reports on a green and facile synthesis method for a ZnO-bentonite nanocomposite and its photocatalytic performance in terms of the degradation of organic dyes under solar radiation. ZnO nanoparticles were successfully supported on natural bentonite using an aqueous fruit jujube extract as a reducing agent, and the biosynthesized ZnO-bentonite nanocomposite was characterized by various techniques, including SEM, TEM and XRD. The results show an efficient degradation of organic dyes (methylene blue and eriochrome black-T) without using any toxic reducing agents under solar irradiation. The nanocomposite was found to eliminate more than 95% of dye molecules and 80% of total organic carbon (TOC) from the aqueous solution after four hours. Moreover, the biosynthesized ZnO-bentonite nanocomposite showed a stable performance and high tolerance to the reaction conditions, and it was reused in three cycles with negligible loss of activity.