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 demonstrated that the mangrove Sonneratia ovata leaf extract is a promising resource for the biosynthesis of zinc oxide nanoparticles (ZnO NPs), which have potential applications in biomedical fields and wastewater remediation. X-ray diffraction analysis revealed that these nanoparticles have a hexagonal wurtzite structure. Optical measurements indicated the presence of a band gap at 3.19 eV. Morphological studies indicated a mixture of rod-shaped and small spherical nanoparticles. The observed physicochemical properties of the green-synthesized ZnO NPs significantly surpassed 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 was shown to be dependent on dye concentration, dye pH, and catalyst concentration. The highest degradation rates of 88.5 %, 98.6 %, and 89.4 % 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 highlighted 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.