Evaluation of biogenic zinc oxide nanoparticles from Sonneratia ovata leaf extract for multivariate factorial photocatalytic and biological activities

The presence of dyes from industrial effluents (such as textile, paper, and leather industries) in water bodies is a significant source of pollution, posing ecological risks that necessitate their removal. The present study has shown that Sonneratia ovata leaf extract is promising for the eco-friendly and non-toxic biosynthesis of zinc oxide nanoparticles (ZnO NPs), which have potential applications in both biomedical fields and wastewater remediation. X-ray diffraction analysis reveals that these nanoparticles have a hexagonal wurtzite structure. Optical measurements indicate the presence of a band gap at 3.19 eV. Morphological studies indicate a mixture of rod-shaped and small spherical nanoparticles. The observed physicochemical properties of green-synthesized ZnO NPs significantly surpass the chemically prepared ZnO NPs following a similar synthesis approach. The photocatalytic efficiency of the biosynthesized nanoparticles was tested under UV light irradiation to degrade ethidium bromide dye. This degradation efficiency is shown to be dependent on dye concentration, dye pH, and catalyst concentration. The highest degradation rates of 88.54 %, 98.61 %, and 89.43 % for ethidium bromide dye, respectively, are for dye concentration, dye pH, and nanocatalyst concentration following a first-order kinetic model. Furthermore, the stabilized nanoparticles derived from the green synthesis using S. ovata leaves are potent antioxidants, exhibiting antibacterial activity against Staphylococcus aureus and Escherichia coli . These findings highlight the potential of using natural aqueous extracts from S. ovata to produce phytochemical-enhanced nanoparticles with significant photocatalytic degradation of toxic dyes in water bodies and biomedical applications. • Green synthesis of zinc oxide nanoparticles (ZnO NPs) from a widely available mangrove species Sonneratia ovata , was reported for the first time. • The detailed characterization of the mangrove-derived ZnO NPs was carried out using X-ray diffraction, field emission scanning electron microscopy, thermal gravimetric analysis, Fourier-transform infrared spectroscopy and Brunauer-Emmett-Teller analysis; revealing a mixture of rod-shaped and small spherical nanoparticles. • Interestingly, these mangrove-derived ZnO NPs were proven to be effective in wastewater remediation like degrading ethidium bromide under sunlight. • The stabilized ZnO NPs delivered antibacterial activity against Staphylococcus aureus and Escherichia coli , highlighting their potential biomedical applications