Synthesis and Photocatalytic Sterilization Performance of SA/TiO₂

The photocatalyst sorbic acid (SA)/titanium dioxide (TiO₂) was successfully synthesized by sol-gel method and characterized. The composite exhibited regularly spherical particles with the size of 50 nm and the specific surface area of 90.3 m² g^-1, furthermore, it showed mesoporous structure and significantly improved dispersion. SA was grafted on TiO₂ surface by -COOTi and TiO₂ existed as pure anatase phase in the composite. The addition of SA made the band gap of TiO₂ increased from 3.03 to 3.35 eV, which indicting that the composite exhibited a strong response to the ultraviolet light. The optimum preparation parameters of the catalyst were as follows: n(Ti):n(SA) = 1:0.05, ethanol 60 mL, glacial acetic acid 40 mL, hydrothermal temperature 180 °C, hydrothermal time 12 h. The composite could reach the 4.31 log reduction of E. coli, with the optimum catalyst dosage of 0.7 g L^-1, irradiated by UV light for 60 min. SA/TiO₂ was an environmentally friendly, non-toxic and safe sterilized nanocomposite material appropriate for future bactericidal applications, providing a new way to effectively increase the dispersion of TiO₂ particles to achieve superior photocatalytic sterilization efficiency.