Terminalia catappa Leaf Extract as a Capping Agent for ZnO Nanoparticle Synthesis via Sol-gel Method and its Microbial Effects on Selected Fungi and Bacterial

Abstract

This study presents a reliable process for synthesizing ZnO nanoparticles using a green method. In this approach, we harness Terminalia catappa leaf extract as an effective chelating and capping agent to synthesize ZnO nanoparticles from zinc nitrate hexahydrate salt through a sol-gel method, employing Response Surface Methodology (RSM) and its microbial assessment. Optical properties of the ZnO nanoparticles were investigated using UV-visible spectroscopy, and determined their band-gap to range between 4.13 and 5.175 eV. To explore the outcomes, Response Surface Methodology (RSM), was employed which revealed that the Model F-value of 2.62 signifies the significance of the model for the response. Furthermore, when examining the contour plot relating the inhibition zone to temperature and plant extract dosage, we found that an increase in dosage and decrease in temperature resulted in an increase in the bandgap. This method of biosynthesizing zinc oxide nanoparticles through Terminalia catappa leaf extract offers effect against the bactieria and fungi such as; Escherichia -coli, Straphylococcus aureus, Pseudomonas aeuginosa and Trichophyton rubrum, Penicillium marnaffei, Atteneria spp respectively. Therefore, ZnO nanoparticles though this route gives an eco-friendly and more straightforward alternative to chemical and physical synthesis techniques for various environmental applications.