Photocatalytic Degradation of Phenol from Textile Wastewater Using Rutile and ZnO-NPs Doped Rutile Nanocomposite

Abstract

This research focuses on the photocatalytic degradation of phenol from textile wastewater. The objective is to synthesize and characterize zinc oxide nanoparticles and a rutile-ZnO nanocomposite and compare their degradation performance on phenol from textile wastewater. Zinc oxide nanoparticles (ZnO-NPs) were synthesized via a green method by mixing zinc nitrate hexahydrate with Mangifera indica leaf extract. The synthesized nanoparticles were incorporated into rutile (TiO2), a photocatalyst often limited by its band gap and high recombination rate, to obtain the rutile-ZnO-NPs nanocomposite. The particle size distribution of the synthesised ZnO-NPs was assessed using dynamic light scattering (DLS) and the morphology, surface area of ZnO-NPs, pure rutile, and the rutile-ZnO-NPs nanocomposite were determined using scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analysis. The photocatalytic potential of rutile and rutile-ZnO-NPs to degrade phenol from textile wastewater was investigated under three conditions: sunlight, UV lamp, and darkness. The SEM results revealed that the materials have good morphological properties, and the BET results indicated that the synthesised material have relatively large surface area. The rutile-ZnO-NPs demonstrated superior photocatalytic activity under sunlight and artificial light, with degradation efficiencies of 94.87% and 91.66%, respectively, compared to pure rutile's 86.70% and 83.54%. The kinetics of phenol degradation followed pseudo-second order model suggesting chemisorption involving valence forces by sharing or exchanging electron. The doping of ZnO-NPs into rutile matrix enhanced the photocatalytic activity of the nanocomposite.