Highly efficient multifunctional Ag/TiO2 nanotubes/Ti plate coated with MIL-88B(Fe) as a photocatalyst, adsorbent, and disinfectant in water treatment

Multifunctional MIL-88B(Fe)-Ag/TiO2 nanotubes/Ti plates were prepared via dip-coating process. Pollutant removals from aqueous solutions were investigated using three different reactions: (1) adsorption of heavy metal ion (Pb2+ and Cd2+), (2) photocatalytic degradation of methyl orange dye (MO), and (3) antibacterial effect for Escherichia coli (E. coli) degradation. Photocatalytic results for dye degradation under UV light irradiation proved the highest activity of the MIL-88B(Fe)-Ag/TiO2 nanotubes/Ti plates. The degradation rate constant of MIL-88B(Fe)-Ag/TiO2 nanotubes/Ti plates was approximately four times as that of pure TiO2 nanotubes/Ti under UV irradiation. In addition, this plate showed the effective removal of heavy metal ions by sorption process. The adsorption of Pb2+ and Cd(2+)on the MIL-88B(Fe)-Ag/TiO2 nanotubes/Ti plates reached a maximum capacity of 113 and 138mg/g, and this value was approximately 1.6 times as that of pure TiO2 nanotubes/Ti. In addition, the multifunctional composite plates demonstrated great antibacterial activities towards E. coli. All bacteria colonies killed after 60min photocatalytic treatment on MIL-88B(Fe)-Ag/TiO2 nanotubes/Ti plates. The results show the importance of a cooperative effect between the MIL-88B(Fe) metal organic framework (MOF) and Ag/TiO2 nanotubes/Ti plates. The simultaneous removals of these pollutants with the high efficiency showed an facile approach for the polluted water treatment via the newly fabricated MIL-88B(Fe)-Ag/TiO2 nanotubes/Ti plate with multiple functions.