Green synthesis of zinc oxide nanoparticles using Ficus carica leaf extract and their bactericidal and photocatalytic performance evaluation

Abstract

Zinc oxide nanoparticles (ZnO NPs) are obtained through biological method using phytochemicals present in leaf extract of Ficus carica (F. carica) tree. The scanning electron microscope images have indicated formation of small spherical ZnO NPs in the form of clusters whose diameter ranges between 30 and 40 nm having mean diameter of 35 nm. The energy-dispersive X-ray spectrum of the ZnO NPs has disclosed existence of Zn and O alone that revealed their pristine property. The X-ray diffraction pattern has exemplified several sharp crystalline peaks that are indexed to ZnO with hexagonal wurtzite structure and its average crystallite size is 33.39 nm. The Fourier-transform infrared spectrum of the ZnO NPs has unveiled bands with intense absorption at 458 and 494 cm−1 that correspond to the ZnO. The ZnO NPs have demonstrated high bactericidal activity against Escherichia coli and Klebsiella pneumoniae strains with inhibition zone value of 17 mm. The photocatalytic performance of the green synthesized ZnO NPs has showed significant decolorization of methylene blue (MB) dye at 60 min of natural sunlight irradiation. A maximum MB degradation efficiency of 95.34% is noticed at an irradiation time of 70 min. The reusability results reveal that the green synthesized ZnO NPs photocatalyst has considerable photostability and reusability during the degradation of MB dye. Hence, the F. carica leaf extract is viewed as an appropriate green resource to prepare ZnO NPs with bactericidal and photocatalytic application prospects.