Green synthesis of ZnO nanoparticles using Citrullus lanatus fruit extract and their potential for microwave absorption

Abstract

Nanotechnology is a developing arena of science focuses on the manufacturing use of nanoparticles (NPs), of the size ranges between 1 and 100 nm, which are categorized into different classes such as inorganic, organic, ceramic and carbon-based nanoparticles. Zinc Oxide (ZnO) nanoparticles (NPs) are perceiving amazing progress during the past few periods due to its exclusive and vital properties in many applications. Newly, green synthesis method of NPs is competing in contradiction of traditional chemical and physical methods by avoiding the use of many toxic compounds, and costly equipment. Accordingly, in this study, watermelon (Citrullus lanatus) rind extract has been used for producing ZnO NPs as a reducing, capping and stabilizing agents. This technic is simple, environmentally friendly and green. UV–vis spectra indicated the formation of Zinc Oxide nanoparticles represented by the change of a colorless liquid to brownish solution. The involvement of the functional groups presents in (Citrullus lanatus) rind extract in both the reduction and capping of nanoparticles was shown through Fourier transform infrared spectroscopy (FTIR). Additionally, the mechanism of formation ZnO NPs from (Citrullus lanatus) rind extract has been thoroughly delineated. This study displayed that (Citrullus lanatus) rind extract is a suitable medium for manufacturing spherical, monodisperse, highly crystalline and wide band gap ZnO NPs. This study emphasizes the potential of ZnO thin films as a promising material for microwave absorption applications, particularly for coating microwave oven gates. It also paves the way for using sustainable resources to develop high-performance materials capable of absorbing unwanted microwave radiation. © 2025 Elsevier B.V.