ZnO nano-flowers from Carica papaya milk: Degradation of Alizarin Red-S dye and antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus

ZnO nanoparticles (NPs) with various morphologies were synthesized via bio-mediated route using Carica papaya milk (CPM) latex as fuel. The formation of ZnO nanostructures (NSs) were characterized by SEM, TEM, HRTEM and FTIR. The influence of CPM concentration on the structure, morphology, UV absorption, PL emission and photocatalytic activity of ZnO NSs were investigated. The possible formation of NSs was also explained. ZnO NSs exhibited warm white emission with CIE chromaticity coordinates (0.40, 0.43) with an average CCT value of 3608 K. The various morphologies of NSs were probed for the photocatalytic degradation of Alizarin Red-S. The enhanced photocatalytic activities of ZnO nano-flower was attributed to small crystallite size, more surface defects, wide band gap and capability for reducing the electron-hole pair recombination. The recycling ability of the nano-flower ZnO was also evaluated with negligible decrease in the degradation efficiency occurred even after the fourth run. Further, ZnO nano-flower showed significant antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus compared to Klebsiella aerogenes and Pseudomonas desmolyticum stains. These results show great promise of multifunctional ZnO NSs for useful applications.

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