Synthesis and characterization of ZnO nanoparticles using aqueous extract of Becium grandiflorum for antimicrobial activity and adsorption of methylene blue

Abstract Nanotechnology is a recent field of modern research dealing with synthesis, strategy and manipulation of particle’s structure in size range of 1–100 nm. This study introduces one of the methods of synthesis of nanoparticles, i.e., green synthesis of ZnO NPs using aqueous leaf extract of Becium grandiflorum (AM: ‘Yedegamentisie’). The biomolecules of the plant extract (such as phenols, flavonoids, saponins, glycosides, steroids, tannins and alkaloids) were used as capping and reducing agent during synthesis of ZnO NPs. Response surface methodology coupled with Box-Behnken design (RSM-BBD) was used to optimize the synthesis of ZnO NPs and adsorption studies of the as-synthesized ZnO NPs. Then, ZnO NPs was characterized using different spectroscopic and microscopic instruments such as UV–Vis spectroscopy, FTIR, XRD and SEM–EDS to consider its purity, shape and crystallinity. UV–Vis analysis showed peaks in the range 305–312 nm due to synthesis of ZnO NPs. FTIR analysis showed the availability of different phytochemicals in the plant extract and synthesis of ZnO NPs at 490 cm −1 . Powder XRD patterns confirmed formation of phase pure wurtzite structures of ZnO NPs. The synthesized ZnO NPs were used to remove MB dye from aqueous solution by acting as a photocatalyst and adsorbent as well as, it also showed antimicrobial activity against two gram positive ( Staphylococcus epidermidis , Staphylococcus aureus ) and three gram negative ( Escherichia coli , Klebsiella pneumonia , Pseudomonas aeruginosa ) bacteria.