Hydrothermal Synthesis, Characterization, and Enhanced Antibacterial Activity of ZnO Nanoparticles against Waterborne Pathogens

Clean water access remains a global challenge due to the high costs and hazardous byproducts from conventional chemical disinfectants. This study explores zinc oxide (ZnO) nanoparticles as an innovative antibacterial agent for water disinfection, leveraging their high surface area and ability to generate reactive oxygen species (ROS) that disrupt bacterial cell walls. ZnO nanoparticles were synthesized via hydrothermal method and characterized using X-ray diffraction (XRD), UV-vis spectroscopy, and scanning electron microscopy (SEM). XRD confirmed high-purity hexagonal wurtzite ZnO with nine distinct peaks, UV-vis revealed an absorbance peak at 350-380 nm, and SEM showed spherical morphology. Antibacterial efficacy was tested against Escherichia coli (Gram-negative) and Bacillus cereus (Gram-positive) using disk diffusion assays. B. cereus exhibited greater sensitivity, suggesting ZnO nanoparticles primarily disrupt positively charged cell membranes via ROS-mediated oxidative stress. These findings highlight ZnO nanoparticles' potential as a sustainable water treatment solution, though further research is needed to address scalability and long-term stability.