Regulating surface-pore structure of PES UF membrane by addition of "active" nano-CaCO3

A small surface-pore ultrafiltration membrane with a high surface porosity was fabricated from a polyether sulfone (PES) dope solution containing a small quantity of CaCO3 nanoparticles (nano-CaCO3), which coagulated in dilute HCl solution. During membrane formation, CO2 nanobubbles were in-situ generated to delay phase inversion, which ameliorated the membrane structure and performance because CO2 nanobubbles are amphiphobic to water and solvent. With increasing nano-CaCO3 content (from 0 to 0.15%) in the dope solution, the surface porosity and the surface-pore density of the obtained PES UF membrane were markedly increased from 1.76 to 6.50% and from 8.31 x 10(14) to 5.08 x 10(15) m(-2), respectively. Nonetheless, the surface-pore size decreased from 13.35 to 8.29 nm, and so as the distribution. The optimal membrane exhibited a high pure water flux (698.2 L.m(-2).h(-1)) and a high rejection to bovine serum album (>99%) with a moderate anti-fouling ability. This work would be of great significance for precision separation in biopharmaceutical, food processing, and other related applications. (C) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.