Photocatalytic Degradation of Acid Blue 25 Dye in Wastewater by Zinc Oxide Nanoparticles

Abstract

This study investigates the photocatalytic degradation of Acid Blue Dye using zinc oxide nanoparticles synthesized from Senna siamea flower extracts (ZnO-S.S.). The synthesized nanoparticles were investigated using Transmission Emission Spectroscopy (TEM) and Scanning Electron Microscope (SEM), which made it possible to reveal the spherical shape of ZnO-S.S. nanoparticles. Themogravimetric Analysis – Differential Thermal Analysis (TGA-DTA) revealed high thermal stability of ZnO-S.S. with an insignificant weight loss as temperature increases from 600 °C to 846.9 °C. While Energy Dispersive X-ray analysis (EDX) reveals the elemental composition and atomic weight percentage as C (4.8%), O (11%), S (6%) and Zn (78.2%). The synthesized nanoparticles ZnO-S.S. used to degrade Acid Blue dye contaminated waste water under visible light irradiation. Exhibits an optimum degradation efficiency of 99% achieved in 150 minutes using a catalyst dosage of 150 mg at an initial acid blue concentration of 10 mg/L. The degradation process best conformed to the pseudo first order kinetics pathway. In conclusion the study established that the synthesized catalyst exhibits good efficiency and utility in degrading dye contaminated wastewater. However, further studies are recommended on the influence of other indicators such as light intensity, temperature and pH on the degradation process.