Comparison of physicochemical properties and antibacterial activities of silver-doped titanium dioxide nanoparticles synthesized by sol-gel and coprecipitation methods based on different titanium crystalline forms of dioxide nanomaterial

Abstract

Abstract This research aims to synthesize silver-doped titanium dioxide (Ag-TiO2) nanoparticles using sol-gel and coprecipitation methods and evaluation the antibacterial behavior of TiO2 and Ag-TiO2 nanoparticles against Staphylococcus aureus (S. aureus), a Gram-positive bacteria, and Escherichia coli)E. Coli(, a predominant Gram-negative bacteria. Also, the optimal conditions were investigated based on the anatase phase of TiO2 due to its higher antibacterial activity than the rutile form. It was observed that temperature and pH have an important role in the phase change of TiO2 during the fabrication of nanoparticles. The Ag-TiO2 nanoparticles at different percentages of Ag 5, 10, 15, and 20% were used at two pH ranges of 4-4.5 and 8-8.5, and three temperatures of 450, 550, and 700°C. According to our findings, the temperature of 450°C and pH = 8-8.5 are suitable for forming the anatase phase, and the temperature of 700°C and PH = 4-4.5 are suitable for forming the rutile phase. It was observed that Ag-TiO2 with the percentages 15%-20% is doped with Ag and PH = 8-8.5, and a temperature of 450°C are favorable conditions for antibacterial activities. Identification of crystalline phases and the crystallite size estimation were investigated using the X-ray Diffraction (XRD) method. The XRD spectrum of TiO2 shows that the anatase phase is the most abundant at 450°C. Although at 550°C, anatase and rutile phases are present, it was confirmed that at 700°C and above, the rutile phase is the most abundant.. Antibacterial behavior of synthesized nanoparticles against Staphylococcus aureus and Escherichia coli (E. Coli) bacteria were evaluated by disk diffusion test method, and it was observed that the antibacterial activity of TiO2 improves by Ag doping.