Imidazolium functionalized anion exchange membrane blended with PVA for acid recovery via diffusion dialysis process

• Anion exchange silica precursor was prepared.
• Imidazolium functionalized anion exchange membranes were prepared accordingly.
• Silica incorporation provides enhanced thermal and mechanical stabilities.
• Prepared membranes showed excellent diffusion dialysis performance for acid recovery.

Anion exchange silica precursor (AESP) was prepared by alkylation of 3-chloropropyltriethoxysilane (CPTS) to 1-methyl imidazole and then the corresponding anion exchange membranes were obtained through sol–gel process of AESP with polyvinyl alcohol (PVA) in the presence of tetraethoxysilane (TEOS). The obtained anion-exchange membranes showed water uptakes (WU) in the range of 44.11–118.86% and ion-exchange capacities (IEC) of 1.34–1.86 mmol/g. The presence of alkoxy-silane groups influenced the membrane properties as they exhibited moderate thermal stability and excellent mechanical properties. When applied for acid recovery through diffusion dialysis process, the membranes exhibited excellent acid flux. The H+ dialysis coefficients (UH) are in the range of 1.87–4.83×10−2 m/h greater than commercial membrane DF-120 (9×10−3 m/h). The obtained separation factors (S) 12.72–52.5 are also greater than that of commercial membrane DF-120 (18.5). Hence, the results of this study suggest that the imidazolium functionalized AEMs can be potentially applied in diffusion dialysis process for acid recovery.

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