Low‐fouling polysulfone ultrafiltration membranes with amphiphilic sulfobetaine polyamide as additive

Abstract

AbstractIn this study, amphiphilic sulfobetaine polyamide (sPA) oligomers with sulfobetaine as end groups and arylamide as backbone were synthesized as the pore‐forming additive for the preparation of polysulfone membranes. This additive showed good solubility and compatibility with the membrane casting solution due to the self‐assembly behaviors of sPA in organic solvent. Moreover, the effects of hydrophobic chain length and additive dosage on membrane morphology, hydrophilicity, permeability, antifouling, and mechanical properties were systematically studied. In view of these results, it can be concluded that the higher content and smaller size of sPA in the casting solution correlated with better filtration and separation performances of the membranes. Results showed that the pure water flux increased from 68.2 L m−2 hr−1 for the pristine membrane to a maximum of 205 L m−2 hr−1 for the blend membrane, meanwhile, the protein rejection ratio was above 95.2% and the flux recovery ratio was promoted from 68.3% to above 85.0%. The fouling resistance of the blend membranes was further demonstrated by significantly reduced protein/bacteria adhesion. And consistent high‐performances in filtration and separation were demonstrated after the blend membranes were treated at 90°C.