C. Vijayaraj, G. Nedunchezhian, S. Sozhaveni and S. Sofiya Lawrence Mary
Abstract
Green synthesis of metal oxide nanoparticles offers a sustainable approach for developing antimicrobial materials. In this study, zirconium oxide (ZrO2) nanoparticles were synthesized using waste Terminalia catappa leaf extract as a natural reducing and stabilizing agent. The synthesized nanoparticles were characterized using UVâVisible spectroscopy, FTIR, XRD, SEMâEDX, and TEM analyses, confirming the formation of crystalline ZrO2 nanoparticles with an average crystallite size of 24 nm and particle size of approximately 27 nm. Antibacterial activity was evaluated against selected Gram-positive and Gram-negative bacteria using the agar well diffusion method. The nanoparticles exhibited significant antibacterial activity, with the highest inhibition observed against Staphylococcus aureus (22 ± 0.6 mm), followed by Bacillus subtilis (20 ± 0.5 mm), Escherichia coli (18 ± 0.5 mm), and Pseudomonas aeruginosa (16 ± 0.4 mm). The antibacterial effect was attributed to reactive oxygen species generation and disruption of bacterial cell membranes. The results demonstrate that waste-derived ZrO2 nanoparticles are promising eco-friendly antibacterial agents with potential applications in environmental sanitation and water disinfection.