Preparation of Al2O3/PU/PVDF composite membrane and performance comparison with PVDF membrane, PU/PVDF blending membrane, and Al2O3/PVDF hybrid membrane

In this study, Al2O3/polyurethane/polyvinylidene fluoride (Al2O3/PU/PVDF) composite membrane was prepared via the thermally induced phase separation process. Pure PVDF membrane, PU/PVDF blending membrane, and Al2O3/PVDF hybrid membrane were also prepared for comparison. These membranes were characterized by means of contact angle test, mechanical properties test, Fourier transform infrared (FT-IR) spectroscopy, atomic force microscopy (AFM), and differential scanning calorimetry (DSC). In addition, the separation performance of membranes was evaluated in terms of water flux and rejection ratio. The results showed that the Al2O3/PU/PVDF composite membrane had better hydrophilicity and mechanical properties compared with pure PVDF membrane, PU/PVDF blending membrane, and Al2O3/PVDF hybrid membrane. FT-IR test confirmed the introduction of the hydrophilic groups, such as hydroxyl and carbonyl, which are responsible for the enhancement of the hydrophilicity of Al2O3/PU/PVDF composite membrane. The AFM results showed that the Al2O3/PU/PVDF composite membrane had the lowest roughness, manifesting its improved anti-fouling properties. Furthermore, DSC results revealed that the crystallinity of PVDF polymer matrix decreased with the introduction of the functionalized Al2O3 nanoparticles.