Magnetic induced fabrication of core-shell structure Fe3O4@TiO2 photocatalytic membrane: enhancing photocatalytic degradation of tetracycline and antifouling performance

Abstract How to endow the photocatalytic membrane with excellent efficiency and high permeability has always troubled scientific researchers. Herein, this work proposed an alternative strategy to controllably induce magnetic core-shell structured Fe3O4@TiO2 nanoparticles to move towards the membrane surface under magnetic field, significantly maintaining a high-water flow rate and enhancing the photocatalytic degradation efficiency. The presence of Fe3O4 in Fe3O4@TiO2 facilitates the electron-hole separation efficiency and maintains the high redox ability of photogenerated electrons in TiO2. The characterization results indicated the Fe3O4@TiO2 nanoparticles were successfully migrated to the membrane surface. As expected, the FTM(Y) had higher porosity (85.56%), higher pure water flux (1536.47 L m-2 h-1 bar-1) and better antifouling performance (5.24% of BSA static adsorption) than that of FTM(N) (1054.26 L m-2 h-1 bar-1, 6.62%). Meanwhile, the FTM(Y) exhibited excellent photocatalytic and self-cleaning activity, the FTM(Y) showed 1.3 times enhancement in visible light (λ>420 nm) driven photocatalytic degradation efficiency of tetracycline compared to that of the FTM(N) without magnetically induced. The ·O2- and ·OH radicals and photogenerated h+ played the primary role in photocatalytic degradation process. This work provides new insight into the design of highly efficient photocatalytic membrane to treat wastewater and enhance water purification.