Synthesis of ZnO nanoparticles using an ionic liquid and investigation of their antibacterial activity

Zinc oxide (ZnO) is a wide band-gap semiconductor oxide (3. 37 eV). ZnO nanoparticles have selective toxicity to bacteria but exhibit minimal effects on human cells. Ionic liquids (ILs) are a new class of chemical compounds which have many extraordinary properties and are able to create green chemical environments in order to perform chemical processes and are an appropriate alternative for organic and inorganic solvents. In this work ZnO nanoparticles were synthesized by a green method based on reaction of zinc acetate and sodium hydroxide in، IL 1-butyl-3-methyl imidazolium chloride under ultrasonic irradiation. Surface morphology and size of ZnO nanoparticles was characterized by scanning electron microscopy (SEM). X-ray diffraction pattern (XRD) indicated that ZnO has hexagonal wurtzite structure. Formation and purity of the ZnO nanoparticles was more confirmed with optical analyses such as UV-Vis spectroscopy and Fourier transform infrared spectroscopy (FT-IR). Specific surface area and porosity of synthesized ZnO was investigated by Brunaur-Emmett-Teller (BET) analysis. The antibacterial activity of ZnO nanoparticles against Escherichia coli (E. coli) was studied by a colony forming count (CFU) method. Results confirmed that the sample had high antibacterial activity.