Antifouling sulfonated poly(arylene ether ketone)s composite nanofiltration membranes prepared by coating

Coating the charged aromatic polymers on ultrafiltration membranes is a feasible strategy to fabricate antifouling nanofiltration (NF) membranes. However, these NF membranes haven’t achieved high rejection and also are very limited because such polymers should be soluble in commonly polar solvents. Sulfonated poly(arylene ether ketone)s (sPAEKs) generally show poor solubility in commonly polar solvents due to their rigid polymer backbones, thus they could not be employed as the coating materials of NF membranes at present. Herein, the soluble sPAEKs in commonly polar solvents are synthesized by attaching methyl side groups to their polymer backbones. Accordingly, these sPAEKs could be coated on ultrafiltration membranes to prepare the antifouling NF membranes. Moreover, the Lewis acid-base interactions between the carbonyl and cation of the sPAEKs coating layer could improve rejection. Besides, their hydrophilic sPAEKs coating layer is favorable for improving permeability. Therefore, the sPAEKs coating layer endows the as-made membrane with excellent nanofiltration performances, such as an antibiotic rejection of 98%, a flux of 31.8 LMH/bar, an antibiotic/NaCl selectivity of 43.6, and a flux recovery rate of 98% for the foulant of bovine serum albumin. It still showed excellent resistance to chlorine oxidation because of the aromatic backbone of the sPAEKs coating layer. This fabrication strategy paves a facile way to achieve high performance NF membranes.