Bimetallic Au/Ag decorated TiO2 nanocomposite membrane for enhanced photocatalytic degradation of tetracycline and bactericidal efficiency

Integration of photocatalysis with membrane processes is a promising strategy for water treatment. In the present work, an alternative bimetallic Au0.1Ag0.9 (mass ratio of Au or Ag to TiO2) nanoparticles decorated TiO2 nanorods embedded in cellulose acetate (Au0.1Ag0.9/TiO2/CA) membrane has been developed for enhanced photocatalytic degradation of antibiotics (tetracycline, TC) and killing pathogenic bacteria. The Au0.1Ag0.9/TiO2/CA membrane maintained the good crystallinity and pore accessibility of CA membrane, in which the decoration of Au0.1Ag0.9 nanoparticles significantly improved the visible light utilization rate and charge separation. During the static photocatalytic degradation system, the TC degradation rate of optimal Au0.1Ag0.9/TiO2/CA membrane could reach ca. 90% with visible light irradiation for 120 min, much higher than those of the monometallic Au-1/TiO2/CA and Ag-0.1/TiO2/CA membranes. The TC degradation rate of Au0.1Ag0.9/TiO2/CA membrane could be further improved by using the dynamic continuous degradation system. Moreover, the Au0.1Ag0.9/TiO2/CA membrane displayed high bactericidal efficiency of E. coil, which could be extremely enhanced under visible light irradiation due to its high photocatalytic activity. This work provides an alternative and highly effective photocatalytic membrane for removing antibiotics and bacteria from water.