Preparation and characterization of acid and solvent resistant polyimide ultrafiltration membrane

Abstract In this study, a new type of polyimide (PI) composite material was synthesized by a two-step method using 2,3,5,6-tetramethyl-1,4-phenylenediamine (TMPDA), 4,4′-methylenedianiline (MDA), and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA). The PI material was then used to prepare an ultrafiltration (UF) membrane by phase inversion method. The membrane showed a dense surface layer, a porous sublayer, and fully developed finger-like macrovoids at the bottom, which had excellent hydrophilicity and antifouling property. In the recovery experiments with a protein solution, the PI membrane displayed a satisfactory water flux recovery ratio of 90.03%. The PI membrane can operate stably in 1 mol L−1 hydrochloric acid solution, and the retention rate of BSA remains at 93%. In addition, the flux of the membrane is 325.60 L m−2 h−1 and the BSA retention rate the retention rate is still higher than 95% after soaking in various solvents for 7 days.