Synthesis and Characterization of Ultrahigh Ion-Exchange Capacity Polymeric Membranes

Abstract

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 cm2 s–1 for Na+, 2.57 × 10–7 cm2 s–1 for Ca2+, 1.45 × 10–7 cm2 s–1 for Cu2+ regarding CEMs, and 7.72 × 10–7 cm2 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.

Advanced functional polymer materials

“…For instance, Zhao et al chose AA for fabricating cationic-exchange membranes (CEM) and 2-vinylpyridine (2VP) for fabricating anionic-exchange membranes (AEM). 636 The new method yielded ultrahigh IECs of 7.88 mequiv g À1 for CEM and 6.27 mequiv g À1 for AEM, which are 8.8 and 7.0 times higher than that of Nafion 117 (0.89 mequiv g À1 ), respectively.…”

Anion Exchange Membrane Based on Interpenetrating Polymer Network with Ultrahigh Ion Conductivity and Excellent Stability for Alkaline Fuel Cell

“…However, high IEC value is usually accompanied by high dimensional swelling which leads to the deterioration of mechanical stability of AEMs. [10][11][12] In this case, crosslinking technology was used to suppress the undesirable excessive dimensional swelling. [13][14][15][16][17] Nonetheless, crosslinking of polymer chains could hinder the ion transport in reverse; thus, specific crosslinking method for each polyelectrolyte should be carefully designed to balance the dimensional swelling and ion conductivity.…”

Cation-Exchange Membranes with Controlled Porosity in Electrodialysis Application

“…Membrane technology has been widely used in industrial applications as a promising technology for wastewater treatment. 1 Compared to other membrane processes, electrodialysis (ED) has been extensively used for the production of potable water from brackish water sources, the recovery of valuable metals from the effluents of the metal-plating industry, the production of high-quality industrial process water, and the treatment of certain industrial effluents, because of its high efficiency, environmental benignity, and operational simplicity. 2 As shown in Figure 1, five parts are essential for an electrodialysis process, including a direct current (dc) supply, electrodes, ion-exchange membranes, solvents, and electrolytes.…”

“…However, the direct discharge of industrial wastewaters potentially threatens the receiving water body when no proper treatment is applied. Membrane technology has been widely used in industrial applications as a promising technology for wastewater treatment . Compared to other membrane processes, electrodialysis (ED) has been extensively used for the production of potable water from brackish water sources, the recovery of valuable metals from the effluents of the metal-plating industry, the production of high-quality industrial process water, and the treatment of certain industrial effluents, because of its high efficiency, environmental benignity, and operational simplicity .…”