Enhanced visible light induced dye degradation and antibacterial activities of ZnO/NiO nanocomposite synthesized using Clitoria ternatea flower extract

Abstract

In this study, ZnO/NiO Nanocomposites (NCs) were prepared using a rapid, simple and eco-friendly green synthesis method using medicinal flower extract of Clitoria ternatea and their visible light assisted dye degradation and antibacterial properties were investigated. The synthesised ZnO/NiO NCs were characterised by ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), High resolution transmission electron microscopy (TEM) and Selected area electron diffraction (SAED) studies. XRD results revealed that ZnO/NiO NCs exhibit hexagonal wurtzite and cubic crystal structure with an average crystallite size of 18 nm. HRTEM images revealed roughly spherical and hexagonal morphology with an average particle size of 23 nm. The antibacterial activity of ZnO/NiO NCs examined against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria using well diffusion method indicated significant antibacterial activity. The photocatalytic activity of the ZnO/NiO NCs showed 83.4 % and 84.4 % of dye degradation efficiency, respectively against Bromophenol Blue (BPB) and Crystal Violet (CV) dye for 150 min under sun light irradiation. The result shows that the ZnO/NiO NCs investigated in this study exhibited a strong potential agent and was successful in the removal of dye from wastewater.