Green Synthesis of Zinc Oxide Nanoparticles (ZnO) Using Banana Peel Extract and Their Application in the Removal of Methylene Blue Dye from Contaminated Water

Abstract

In this study, zinc oxide nanoparticles (ZnONPs) were synthesized using an eco-friendly green approach, employing banana peel extract as a reducing and stabilizing agent. The synthesized ZnO was characterized by AFM, XRD, SEM, EDX, FTIR, and UV-Vis spectroscopy to determine its structural and morphological features. The photocatalytic activity of ZnONPs was assessed for methylene blue (MB) dye removal from contaminated water under ultraviolet (UV) and sunlight irradiation. High degradation efficiency was achieved, with 99.1% of the dye removed within 60 minutes using 0.05 g/L of catalyst in 50 mL of 10 ppm MB solution at pH 10, under both light sources. These results confirm the effectiveness of biosynthesized ZnO NPs in removing organic dyes from water. In addition, optimal degradation conditions were studied, and the catalyst’s reusability was evaluated. After four reuse cycles, ZnONPs retained a degradation efficiency of 87.6%, indicating good stability and reusability. These findings suggest that green-synthesized ZnONPs are a promising candidate for large-scale water purification applications.