Strong acid- and solvent-resistant polyether ether ketone separation membranes with adjustable pores

Polyether ether ketone (PEEK) is composed of repeating phenyl ether and benzophenone units and exhibits strong chemical resistance in harsh solvents due to their inherent structural characteristics. In view of its stability and un-processability, the traditional methods of preparing membranes limited further application. In this work, we proposed a facile route toward the preparation of PEEK membranes via traditional non-solvent-induced phase separation (NIPS) and a facile one-step heat treatment for the first time to the best of our knowledge. Most intriguingly, the morphologies, pore size, water permeability and selectivity of PEEK membranes could be simply modified by heat treatment. The effect of the pore size on permeability and selectivity was investigated for bovine serum albumin (BSA, 66.4 K Da), rose bengal sodium salt (RB, 1017 Da) and methyl blue (MB, 799 Da). Aside from a high selectivity (rejection higher than 90% for different molecular structures) being obtained, the membranes showed excellent reproducibility in organic solvents and strong acid. Moreover, the separation performance remained unchanged in a long-term operation. The application of this simple and highly economical method expands the research direction of PEEK membranes and promotes the further application in separation and purification.