Synthesis of zinc oxide and silver-doped zinc oxide nanoparticles using sol-gel method and their toxicity assessment upon Staphylococcus aureus and Escherichia coli in contaminated water samples

Document Type : Original Article


1 Department of Environmental Science and Engineering, Tabriz Branch, Islamic Azad University, Tabriz, Iran.

2 Department of Environmental Science and Engineering, Ardabil Branch, Islamic Azad University, Ardabil, Iran.



Background: Nanoparticles (NPs) have spurred recently extensive interest in the area of elimination and/or reduction of microbial load in various water resources. Accordingly, the purpose of this study was to eliminate bacterial contamination from aqueous solutions using synthesized NPs.
Methods: In the present study, zinc oxide (ZnO) and silver ion-doped zinc oxide (Ag/ZnO, 1-6 wt%) nanoparticles were synthesized using the sol-gel process and then characterized for structure, morphology and antimicrobial activity. X-ray diffraction (XRD) was utilized to determine the nanoparticle size and crystal structure. Images from field emission-scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) confirmed the successful production of NPs. The antimicrobial activity of ZnO NPs and Ag1-6%/ZnO NPs against Staphylococcus aureus and Escherichia coli was assessed by agar well diffusion method.
Results: According to the findings, the synthesized ZnO NPs had hexagonal structure and the size of ZnO and Ag5%/ZnO NPs were 32.56 and 12.81 nm, respectively, as well as the FESEM images displayed that the nanoparticle sizes were 77.60 and 47.15 nm, respectively. Based on TEM images, the mean size of ZnO and Ag5%/ZnO NPs was 22.5 and 17.5 nm, respectively. The results revealed that the diameter of the zone of inhibition created by Ag5%/ZnO NPs at a concentration of 0.1 g/mL was 20 mm for S. aureus and 13 mm for E. coli.
Conclusions: The results indicated that E. coli was more resistant than S. aureus, although E. coli was still more resistant at low concentrations.


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