The water disinfection efficiency of Fe3+ and N-doped 3SnO2/TiO2 composite and undoped films was investigated. The water containing E. coli with an initial concentration of 103 CFU/ml was treated by a photocatalytic reactor filled with 60 g of glass fibers coated with the catalytic films for 1-5 circulated cycles. The number of survival bacteria after treatment was evaluated with spread plate techniques. Furthermore, the photocatalytic reaction on degradation of methylene blue dye solution was also investigated in order to observe the correlation between the result of bacteria inactivation of the prepared films and that of photocatalytic activity on methylene blue degradation. It reveals that N-doping in the TiO2 composite films results in shifting absorption wavelength towards visible light, narrowing the energy band gap and acts as photo-generated electrons trapping site, leading to retardation of the electrons-holes recombination, while Fe3+ doping has a main effect on hindrance of anatase crystal growth of the composite films. Therefore, 20N/3SnO2/TiO2 composite thin film exhibits greater photocatalytic activity and disinfection efficiency than those of undoped and Fe3+ doped TiO2 films. It was found that the bacterial inactivation of the prepared films correlates closely to photocatalytic activity performed by degradation of methylene blue dye solution. The 20N/3SnO2/TiO2 composite film can kill E. coli 97% within 5 cycled water treatment (~93 min) while Fe3+/3SnO2/TiO2, undoped TiO2 and UV alone can kill only 62, 65 and 58%, respectively. The 20N/3SnO2/TiO2 films coated on glass fibers are expect to be applied as an antibacterial photocatalyst for water purification.
Fabrication of UiO-66/MIL-101(Fe) binary MOF/carboxylated-GO composite for adsorptive removal of methylene blue dye from aqueous solutions