Green Synthesis of Zinc Oxide Nanoparticles Using an Aqueous Extract of Punica granatum for Antimicrobial and Catalytic Activity

The peel aqueous extract of Punica granatum was utilized to fabricate zinc oxide nanoparticles (ZnO-NPs) as a green approach. The synthesized NPs were characterized by UV-Vis spectroscopy,

Fourier transform infrared (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM),

and scanning electron microscopy, which was attached to an energy dispersive X-ray (SEM-EDX).

Spherical, well arranged, and crystallographic structures of ZnO-NPs were formed with sizes of

10–45 nm. The biological activities of ZnO-NPs, including antimicrobial and catalytic activity for

methylene blue dye, were assessed. Data analysis showed that the antimicrobial activity against

pathogenic Gram-positive and Gram-negative bacteria, as well as unicellular fungi, was observed to

occur in a dose-dependent manner, displaying varied inhibition zones and low minimum inhibitory

concentration (MIC) values in the ranges of 6.25–12.5 µg mL–1. The degradation efficacy of methylene

blue (MB) using ZnO-NPs is dependent on nano-catalyst concentration, contact time, and incubation

condition (UV-light emission). The maximum MB degradation percentages of 93.4 ± 0.2% was

attained at 20 µg mL−1 after 210 min in presence of UV-light. Data analysis showed that there is no

significant difference between the degradation percentages after 210, 1440, and 1800 min. Moreover,

the nano-catalyst showed high stability and efficacy to degrade MB for five cycles with decreasing

values of 4%. Overall, P. granatum-based ZnO-NPs are promising tools to inhibit the growth of

pathogenic microbes and degradation of MB in the presence of UV-light emission.