Synergistic effect of biochar impregnated with ZnO nano-flowers for effective removal of organic pollutants from wastewater

Abstract

The ZnO composite photocatalyst has been proven to be a successful technique for removing organic contaminants from water. Fabricating a cost-effective ZnO composite with excellent photocatalytic efficacy, however, remains a major issue. This research shows how to make biochar-supported ZnO nanoparticles by altering the pomegranate peels biochar/ZnO molar ratio. The 3D flower-shaped ZnO nanoparticles supported by biochar were characterized by ultraviolet (UV), IR (Infrared) spectroscopy, X-ray diffraction method (XRD) and Scanning electron microscopy (SEM). The elemental mapping was done by Electron dispersive spectroscopy (EDS). Band gaps were calculated using Tauc's equation, the value was found to be lowest (2.8 eV) for ZnO-Pomegranate biochar (1:10) whereas for ZnO nanoflowers, it was calculated as 3.2 eV. When the molar ratio of ZnO-Pomegranate biochar (Z-P) was 1:10, with dose of 50 mg per 50 ml, it showed excellent degradation efficiency under UV visible light. This particular molar ratio was found to effective in removing 91% phenol, 94% methylene blue and 90% Rhodamine B from water. The decreased band gap of biochar ZnO composite could be the possible reason for its outstanding removal efficiency in visible region. This study sheds light on the design and preparation of ZnO photocatalysts used in the purification and remediation of the aqueous environment.

Keywords

• ZnO nanoflowers
• XRD
• SEM
• Eco-friendly material
• Environment pollution
• Pomegranate peels