Synthesis of Silver Doped Titanium Dioxide by Wet-Ball Milling Sol–Gel Method for Antibacterial Application

¹ Thammasat School of Engineering, Thammasat University, 99 Phaholyothin Rd., Khlong Loung, Pathumthani 12120, Thailand
² National Nanotechnology Center, National Science and Technology Development Agency, Pathumthani, 12120, Thailand

^* Corresponding author: etippabu@engr.tu.ac.th

Abstract

Titanium dioxide (TiO₂) has been extensively studied as photo-catalyst for water treatment, air purification and antibacterial applications due to its challenging properties such as chemical stability, environmental friendly and strong photocatalytic activity. However, the limitation of TiO₂ on its dependent to ultraviolet radiation for photocatalytic activity is still aroused. In this study, silver doped titanium dioxide (Ag-TiO₂) was synthesized by wet-ball milling sol–gel method (WBMS). Ag-TiO₂ molar ratio was varied from 0% to 10% to study the effect of silver content on the synthesized Ag-TiO₂ characteristics and the ability to apply on antibacterial applications. The objective of this work was to find an optimal concentration of Ag in Ag-TiO₂. Characterization of the particle size, morphology, and surface area of synthesized Ag-TiO₂ were discussed by techniques of transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). Photocatalytic activity was investigated from degradation of methylene blue. Antibacterial activity was conducted by finding minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests performed on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) under dark condition and under visible light. The results demonstrated that the doping of Ag inhibited crystal growth of Ag-TiO₂. The smallest particle size and the highest surface area were obtained from 5% Ag-TiO₂. Also, it was found that methylene blue degradation rate increased to the highest number of 1.62x10⁻³ min⁻¹ when Ag concentration reached 5%, and methylene blue degradation rate reduced when Ag concentration was higher than 5%. The antibacterial activity of Ag-TiO₂ was better than TiO₂. The optimal concentration of 3-5% Ag-TiO₂ was observed from the MIC and MBC tests.