Antibacterial properties of photochemically prepared AgTiO2 membranes

Abstract

Biofouling reduces the membrane performance and has become a problem in many applications. One of the strategies to reduce biofouling is to apply antibacterial materials to the membrane surface, which prevents the attachment and growth of microorganisms. In this study, the surface of flat ceramic supports was covered with TiO2 powder, and silver was applied by photoreduction using a CH3COOAg solution at room temperature. After the photoreduction, AgOx and metallic silver were found on the TiO2 as analyzed by XPS. While a negligible amount of silver was released from the prepared AgTiO2 membranes into water, the dissolution of silver was enhanced in a 0.09 M NaCl solution. The AgTiO2 membranes inhibited the growth of Escherichia coli in dark conditions. The inhibition cannot be explained only by the concentration of silver ions released from the membranes. Microscopic observation showed that direct contact with AgTiO2 kills E. coli. The results showed the possibility of improving the antibacterial activity of membranes by applying an AgTiO2 coating. HIGHLIGHTS AgTiO2 membranes were prepared by photoreduction using the CH3COOAg solution.; Silver oxide was formed by photoreduction with a light intensity of 3.3 mW/cm2.; Silver leaching from the AgTiO2 membranes was negligible in water but enhanced in 0.09 M NaCl solution.; AgTiO2 membranes inhibited the growth of E. coli under dark conditions.; The results showed potential antibacterial activity of silver oxide.;

Keywords

• agtio2
• antibacterial activity
• escherichia coli
• immobilization
• photoreduction