Development of hydrophilic PES membranes using F127 and HKUST-1 based on the RTIPS method: Mitigate the permeability-selectivity trade-off

Abstract

In this study, to mitigate the permeability-selectivity trade-off effect, Pluronic F127 (F127) and HKUST-1 were employed to construct high-performance membranes based on the reverse thermally induced phase separation (RTIPS) method. F127, as a hydrophilic modifier, was applied to increase permeability and resist polyethersulfone (PES) membrane fouling, while the collapse of HKSUT-1 caused by its instability in pure water improved the permeability and selectivity of the membrane. Characterizations demonstrated the successful synthesis of HKUST-1, together with the successful introduction of HKSUT-1 and F127 in PES membranes. It was observed that the membrane prepared by the RTIPS process possessed a uniformly porous surface and sponge-like cross-section with excellent mechanical properties, higher permeability, and selectivity compared to the dense skin and finger-like cross-section of the membrane prepared by the nonsolvent induced phase separation (NIPS) method. Moreover, the permeation and bovine serum albumin (BSA) rejection rate of the optimal membrane reached 2378 L/m2 h and 89.3%, respectively, which were far higher than those of the pure membrane. Hydrophilic F127 and many microvoids formed by the collapse of HKUST-1, played an important role in excellent antifouling properties, high permeability, and selectivity by pure water flux (PWF), flux recovery rate (FRR), BSA flux, and COD removal rate tests. Overall, the membrane with F127 and HKSUT-1 prepared via the RTIPS method not only obtained excellent antifouling properties but also mitigated the permeability-selectivity trade-off.