Sol–gel preparation of PAA-g-PVDF/TiO2 nanocomposite hollow fiber membranes with extremely high water flux and improved antifouling property

High permeability and antifouling property are important performance of filtration membranes for reaching the requirement of real application. In this work, poly(acrylic acid) grafted PVDF (G-PVDF)/TiO2 nanocomposite hollow fiber ultrafiltration membranes were fabricated by combining tetrabutyl titanate in-situ sol–gel process with liquid-induced phase separation. Energy dispersive X-ray (EDX) and EDX mapping scanning spectra confirmed the formation of TiO2 component and uniformly dispersion of TiO2 nanoparticles in nanocomposite membranes with ultrafine size when the TiO2 content was less than 3 wt%. The effect of TiO2 on the membrane performance was systematically investigated. The G-PVDF/TiO2 nanocomposite membranes exhibited extremely high water permeation, improved antifouling property and rejection efficiency as compared to PVDF and G-PVDF membranes. In case of ∼1 wt% TiO2 content, the water flux of G-PVDF/TiO2 nanocomposite membranes reached 974 L/m2 h under 0.1 MPa, which was more than four times of that of PVDF membranes. Simultaneously, G-PVDF/TiO2 nanocomposite membranes displayed greatly reduced amount of protein adsorption to be 24 μg/cm2, which is a seventh of that of PVDF membranes. Two cycles of flux recovery test also indicated that G-PVDF/TiO2 nanocomposite membranes possessed better antifouling property and stability. More important is that the incorporation of TiO2 nanoparticles did not weaken the mechanical strength of the membranes. The superior performance of our G-PVDF/TiO2 nanocomposite hollow fiber ultrafiltration membranes offers a great potential for practical application.

► Nanocomposite hollow fiber membranes were fabricated by in-situ sol–gel process.
► Poly(acrylic acid) grafted PVDF is used as the polymer matrix.
► SEM and EDX showed the well distribution of TiO2 nanoparticles in the membrane.
► The resulted nanocomposite membranes had extremely high water flux.