Photodegradation of organic dyes and antibacterial activity of Escherichia coli and Staphylococcus aureus by ZnO nanoparticles under UVA radiation

Abstract

Zinc oxide (ZnO) nanoparticles were successfully prepared in solutions with the pH of 10 (S-pH10), 11 (S-pH11) and 12 (S-pH12) by sonochemical method combined with calcination. Phase, morphology and photo-emission were characterised by X-ray powder diffraction, Fourier transform infrared spectroscopy, photoluminescence spectroscopy and field emission scanning electron microscopy. UV-visible analysis indicated the photonic absorption of S-pH10, S-pH11 and S-pH12 with 3.55, 3.51 and 3.54 eV direct band gaps, including the BET analytical specific surface areas of 4.73, 6.90 and 9.14 m2/g, respectively. ZnO was tested for photodegradation of methylene blue rhodamine B and methyl orange dyes under UVA radiation. In this research, S-pH12 has the highest photodegradation efficiency. ZnO also tested for antibacterial activity against Escherichia coli and Staphylococcus aureus growth induced by UVA radiation. S-pH10 has the highest antibacterial activity against S. aureus of 97.4 ± 0.20% but S-pH12 has the highest antibacterial activity against E.coli of 35.7 ± 0.10%.