Antioxidant and photocatalytic properties of zinc oxide nanoparticles phyto-fabricated using the aqueous leaf extract of Sida acuta

Abstract

Abstract Nanoparticles have gained considerable attention during the present millennium due to its unique properties and usage of same in all the scientific fields. The present study was aimed to phyto-fabricate zinc oxide nanoparticles (ZnO NPs) from Sida acuta and evaluate its antioxidant and photocatalytic activity against the dye victoria blue (VB). The phyto-fabricated ZnO NPs when subjected for physico-chemical characterization showed an absorbance peak at 373 nm and was spherical in nature. Strong and well-distinguished sharp peaks were noticed in X-ray diffraction analysis with an average size of ∼32.82 nm calculated through Scherrer’s formula. The size was also authenticated through dynamic light scattering analysis and transmission electron microscopy. The Fourier transform-infrared spectroscopy confirmed that the phyto-constituents of the plant extract served as capping/stabilizing agents during the synthesis of ZnO NPs. The atomic force microscopy studies on morphology and geometrics of the synthesized particles indicated that particles were monodispersed with colour difference. In addition, the surface area of ZnO NPs measured by Braunauer–Emmett–Teller experimental studies for adsorption isotherms was found to be 7.364 m2·g−1. The antioxidant efficacy of the phyto-fabricated ZnO NPs offered concentration-dependent antioxidant activity with an IC50 value of 0.74 mg·mL−1. Further, the VB (9 mM) dye degradation studies using the phyto-fabricated ZnO NPs (0.75 g·L−1) resulted in dye degradation of 93% at 40 min in natural sunlight. Further, the reuse and recycling of the photocatalyst for dye degradation offered 70.25% dye degradation ability within 40 min exposure to sunlight at the fifth cycle of reusability thereby indicating effective dye degradation ability of the phyto-fabricated ZnO NPs from the aqueous leaf extract of S. acuta.