Eco-friendly synthesis of zinc oxide nanoparticles using Citrus macroptera peel extract and their role as a photocatalyst and antibacterial agent

This study presents a cost effective green synthesis of zinc oxide nanoparticles (ZnONPs) using Citrus macroptera peel extract via precipitation followed by calcination route. Synthesized ZnONPs was characterized by multiple analytical techniques. The presence of ZnO was indicated by the elemental composition obtained from Energy-dispersive X-ray (EDX) spectroscopic data complemented by distinct Zn-O absorption peaks (435, 436, 442, 446, 450 and 485 cm −1 ) in Furrier Transform Infra-Red spectroscopy (FTIR) data. Also the product showed heterogeneous distribution of particles having size 69.95 nm. X-Ray Diffraction (XRD) profile showed presence of hexagonal wurtzite type ZnO crystal, having crystallinity and crystallite size 51.96 % and 11.62 nm, respectively, with negligible micro-strain, and comparable lattice parameters of zincite mineral. Besides, Transmission electron microscopy (TEM) images correlated with the d -spacing, 2.75 Å for plane (100) and 2.62Å for plane (002) calculated from XRD data. Furthermore, UV-visible spectroscopy directed showed surface plasmon resonance (SPR) band at 384 nm, indicating the high purity of ZnONPs with optical band gap 2.9, lower than bulk ZnO, making it suitable for photocatalytic and antibacterial applications. Synthesized ZnONPs exhibited excellent photocatalytic efficiency, degrading 97 % of methylene blue under solar irradiation, which is about 6.06 times higher as compared to the results found in dark (16 %), following pseudo-first-order kinetics. Alongside, it showed potential inhibition against Escherichia coli, Vibrio cholera, Salmonella typhi , and Staphylococcus aureus . • ZnONPs were sustainably synthesized using Citrus macroptera peel extract. • Formation of crystalline ZnONPs with a size range of 50–100 nm. • Exhibits promising photocatalytic efficacy for the degradation of MB dye (97 %). • Act as promising antibacterial agent against four different bacterial strain.