Stable and efficient composite anion-exchange membranes based on silica modified poly(ethyleneimine)–poly(vinyl alcohol) for electrodialysis

• Anion exchange membrane (AEM) based on silica modified poly(ethyleneimine).
• Simple and green preparation of AEM without the use of hazardous chemicals.
• Trade-off studies between properties, stabilities and electro-osmotic drag of AEM.
• An efficient and stable AEM for electrodialysis.

Anion exchange membranes (AEMs) have found numerous electrochemical applications because of their good conductivity and permselectivity. Herein, we are reporting a method to prepare silica modified poly(ethyleneimine) (SMPEI) with 3-Glycidoxypropyl-trimethoxysilan (GPTMS) by epoxide ring opening reaction. Stable AEMs of different compositions were prepared with SMPEI and a plasticizer poly(vinyl alcohol) (PVA) by acid catalyzed sol–gel followed by formal cross-linking. The reported method is simple and a green alternative for the preparation of AEM without the use of hazardous chemicals. Suitability of prepared AEMs for electrodialytic application was assessed by analyzing their physicochemical properties, stabilities under operating conditions, conductivity, electro-osmotic and chronopotentiometry studies. A highly suitable membrane, SMPEI/PVA-40, exhibited 55.32 mS cm−1 conductivity (in equilibration with 0.04 N NaCl solution at 30 °C), ion-exchange capacity (1.31 meq g−1) and permselectivity (0.79) with good electrodialytic performance. Preparation protocols and properties of the reported composite AEM represent a promising starting point for architecting highly conducting and stable AEMs, but we have to study the trade-off between properties, stabilities and electro-osmotic mass drag before its commercial exploitation.

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