Zinc Oxide Nanoparticles: Applications in Photocatalysis of Dyes and Pearl Millet Seed Priming for Enhanced Agricultural Output

This research examines the environmentally benign manufacture of zinc oxide nanoparticles employing a crude extract from Murraya koenigii leaves as a capping and reducing agent. The considerable peak of synthesized zinc oxide nanoparticles (ZnO NPs) was observed at 335 nm, and the functional groups of plant active metabolites to reduce zinc and evaluate shape and elemental compositions were analyzed using UV–vis spectroscopy, FT-IR, SEM, and EDX analysis, respectively. The average size of synthesized zinc oxide nanoparticles (27.26 nm) was validated by XRD using the Debye–Scherrer’s equation. Zinc oxide nanoparticles were assessed for their efficiency in seed priming, photocatalytic degradation, antibacterial activity, and antioxidant abilities. The biosynthesized zinc oxide nanoparticles were utilized in seed priming, significantly enhancing germination rate (90%), shoot length (5.46 cm), and root length (15.13 cm) at a concentration of 150 ppm in comparison to control. Further, the effect of methyl orange (MO) and methylene blue (MB) dyes on % seed germination and plant growth of hybrid pearl millet was studied in vitro. MO and MB had shown approximately 15 and 46% reduction in seed germination % in comparison to control. Additionally, zinc oxide nanoparticles had shown remarkable photocatalytic degradation of 94.45% against methylene blue and 85.99% against methyl orange. Zinc oxide nanoparticles were also effective against Escherichia coli and Staphylococcus aureus bacteria, with zones of inhibition of 0.45 and 0.35 cm at a 100 mg/mL concentration. Furthermore, zinc nanoparticles observed higher antioxidant activity against DPPH at 80 μg/mL. The present finding highlights the potential of biosynthesized zinc oxide nanoparticles as a sustainable approach to agriculture, environmental remediation, and biological sciences.