Moringa oleifera leaves extract-mediated synthesis of ZnO nanostructures for the enhanced photocatalytic oxidation of erythrosine

Abstract

This study was focused on the development of ZnO nanostructures for the efficient oxidation of erythrosine dye and for studying the antibacterial activity of ZnO. It was observed that the phytochemicals from Moringa oleifera leaves modified the size, shape, crystalline properties and surface chemical composition of the ZnO nanostructures. ZnO nanostructures synthesized with 15 mL Moringa oleifera leaves extract (S-15) demonstrated highly efficient oxidation of erythrosine dye under the illumination of natural sunlight. Various photocatalyst evaluation parameters, such as initial dye concentration, pH of the dye solution, catalyst dose and cycling stability, were studied. The S-15 sample of ZnO exhibited almost 100% dye removal in an alkaline pH of 12 and a low concentration of 4.54 × 10⁻⁵ M. Furthermore, improved antibacterial activity was also observed against E. coli and Bacillus subtilis bacteria strains. The use of Moringa oleifera leaves extract could be considered a low-cost, facile and ecofriendly green synthesis protocol for replacing the use of toxic chemicals and for eliminating the risk of releasing of toxic chemicals into the environment during the synthesis of high-performance nanostructured materials.