Multifunctional bilayer electrocatalytic membrane with high permeability and antifouling property for efficient removal of dye from water

To solve the problem of flux reduction and membrane damage due to membrane contamination and pressure-driven during membrane separation, a new strategy was proposed for the preparation of multifunctional bilayer membrane doped with iron phthalocyanine (FePc) in PVDF matrix. The membrane consisted of an upper PVDF@P-C-FePc conductive polymer layer and a lower hydrophilic cotton fiber (CF) substrate. The CNTs-loaded FePc enhanced the porosity, hydrophilicity and permeability of the polymer layer, and the ·OH generated during the electrocatalytic process endowed the membrane with good self-cleaning properties. The formation of a wettability gradient between the CF and the PVDF@P-C-FePc benefits further water flux enhancement, while the excellent mechanical properties of cotton fiber greatly improve the mechanical strength and reduce membrane damage. With pressure-driven of 0.1 MPa and electrocatalytic conditions of 6 V, the prepared PVDF@P-C-FePc/CF exhibited excellent water flux (493 L$\bullet$m^-2$\bullet$h⁻¹) and a removal efficiency of up to 95 % for 15 mg/L of MB. Because of the good self-cleaning performance, the dye pollutions on the surface were extremely easy to clean, and the flux recovery was close to 100 %, showing good antifouling performance. This proves that the prepared PVDF@P-C-FePc/CF composite membrane possesses the combined advantages of high flux, separation efficiency and antifouling performance at the same time, and shows a broad application prospect in water treatment applications.