Amino-functionalized mesoporous nano-silica/polyvinylidene fluoride composite as efficient ultrafiltration membrane

Ultrafiltration mixed matrix membranes were prepared using polyvinylidene fluoride (PVDF) with functionalized mesoporous amino nano-silica (NS). The prepared functionalized mesoporous amino nano-silica (NS) was characterized using X-ray diffraction, transmission electron microscopy, and Fourier transform infrared. The results indicate that the addition of amino-functionalized nano-silica improves the hydrophilicity of the membrane. Membranes M5 and M6 showed the highest tensile properties. M5 showed a tensile strength of 82.5 kg/m2 and elongation of 25.5%, while the tensile strength of 87.9 kg/m2 and an elongation of 29.3% were found for M6. M6 exhibited an optimal morphology due to the formation of a small dense top layer and a wide finger-like sublayer, affording a permeate flux 347 L/m2h and a rejection of 98.8% for humic acid concentration 3 g/L. M5 exhibited a more compact spongy-like structure, with a permeate flux of 294 L/m2h and rejection of 99.7% for humic acid at concentration 3 g/L. The bovine serum albumin (BSA) was used also as a feed solution in the performance testing, using a feed concentration of 3 g/L. M5 and M6 showed the highest removal percentage for BSA of 99.5% and 99.2%, respectively. The fouling test was carried out using humic acid solutions (10 g/L) and BSA solution (3 g/L). M5 and M6 showed excellent antifouling properties, where FRR of M5 and M6 were, respectively, of 99.71% and 99.43% for humic acid solution, while FRR for M5 and M6 were, respectively, of 98.5% and 97.96% for BSA solution.