Preparation of Small-Pore Ultrafiltration Membranes with High Surface Porosity by In Situ CO Nanobubble-Assisted NIPS.

The fabrication of ultrafiltration (UF) membranes with a small pore size (<20 nm) and high surface porosity is still a great challenge. In this work, a nanobubble-assisted nonsolvent-induced phase separation (BNIPS) technique was developed to prepare high-performance UF membranes by adding a tiny amount of CaCO nanoparticles into the casting solution. The phase inversion occurred in a dilute-acid coagulation bath to simultaneously generate CO nanobubbles, which regulated the membrane structure.