One-pot greener synthesis of zinc oxide nanoflowers using potato, cauliflower, and pea peel extract with antibacterial application

Abstract

The greener synthesis of nanoparticles gives alternatives to conventional methods and holds the advantage of cost and economy with controlled toxicity. In this research work, we have reported the synthesis of zinc oxide (ZnO) nanoflowers (NFs) by using aqueous peels extract of Solanum tuberosum (potato), Brassica oleracea (cauliflower), and Pisum sativum (pea). Magnificent colorful NFs of nearly the same size and morphology were developed from all tested bio-extracts. The average particle size of ZnO NFs tailored from cauliflower, potato and pea were 37.91 nm, 42.37 nm, and 28.6 nm, respectively. The maximum absorption peak for NFs was at 390 nm, and the bandgap calculated through the Kubelka-Munk function for ZnO NFs was between 3.28 and 3.29 eV. ZnO NFs were found thermally stable till 200 °C, and 50% mass loss was between 200 and 400 °C. Antimicrobial efficacy of synthesized NFs was evaluated. They were identified as a robust antibacterial agent, and the inhibitory action at 45 µg/mL was figured out as B. subtilis (25.2 mm) > E. coli (24.1 mm) > S. aureus (21.2 mm) > P. aeruginosa (17.3 mm). The results showed that ZnO NFs could be effectively utilized against Gram-positive and Gram-negative bacteria. Nanoflowers were discovered unrivaled for bactericidal action than precursor material against control. Moreover, comparing this work with published articles about greener synthesis of ZnO NPs displays them as more toxic and versatile.