Covalently cross-linked pyridinium based AEMs with aromatic pendant groups for acid recovery via diffusion dialysis

• The pyridinium based anion exchange membranes with aromatic pendant groups were prepared.
• Dialysis of HCl/FeCl2 waste mixture was experimentally investigated.
• The membranes showed high separation performance in the acid recovery.

In this study, the pyridinium anion exchange precursor was prepared by alkylation of 4-bromomethyl benzoic acid to pyridine and then the corresponding covalently cross-linked pyridinium based AEMs were obtained by esterification reaction through the prepared pyridinium salt and polyvinyl alcohol (PVA) as a base material in presence of tetraethoxysilane (TEOS) as a crosslinker. The prepared anion exchange membranes are characterized by FTIR, SEM, TGA and DMA. Td values are in the range of 322–335 °C. The tensile strength (TS) ranges from 43.74 to 47.23 MPa and elongation at break (Eb) in the range of 262.59–474.44%. The acid dialysis coefficients (UH) are in the range of 1.28–1.88 × 10−2 m/h, greater than the well known commercial membrane DF-120 (9 × 10−3 m/h). The membrane containing 40 wt% of PVA has the highest separation factor (S) of 71.35. Note that the DD tests have been evaluated according to the membrane structure and its composition.

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