Synthesis and Characterization of Ultrahigh Ion-Exchange Capacity Polymeric Membranes

A universal mold casting approach for the preparation of cation-exchange membranes (CEMs) and anion-exchange membranes (AEMs) with ultrahigh ion-exchange capacities (IECs) is developed based on in situ cross-linking polymerization of acrylic acid (AA) and 2-vinylpyridine (2VP), respectively. This new method produced ultrahigh IECs of 7.88 mequiv g –1 for CEM and 6.27 mequiv g –1 for AEM, which are 8.8 and 7.0 times that (0.89 mequiv g –1 ) of Nafion 117, respectively. Also, the prepared membranes demonstrate excellent thermal and chemical stability and acceptable conductivity. As a consequence, the membranes show relatively high performance for ion-exchange application and methanol barrier, exhibiting ion permeabilities of 2.06 × 10 –7 cm 2 s –1 for Na +, 2.57 × 10 –7 cm 2 s –1 for Ca 2+, 1.45 × 10 –7 cm 2 s –1 for Cu 2+ regarding CEMs, and 7.72 × 10 –7 cm 2 s –1 for methanol regarding AEMs. These results indicate that the CEMs and AEMs fabricated from the universal mold casting approach are promising candidates for targeting ultrahigh ion-exchange capacity membranes.