Excellent dimensional stability anion exchange membrane based on PVA/EVOH/PyPECH for acid recovery by diffusion dialysis

Quaternized polyepichlorohydrin (PyPECH) was successfully synthesized by the quaternization reaction between Pyridine and PECH. The correctness of the experimental result was demonstrated through Fourier transform infrared spectroscopy (FTIR) and 1H NMR spectroscopy. With the combination of PyPECH, Polyvinyl alcohol (PVA), Ethylene-vinyl alcohol copolymer (EVOH), and Tetraethyl orthosilicate (TEOS), five different anion exchange membranes (AEMs) for diffusion dialysis (DD) were successfully prepared. The structure of prepared membranes was characterized and analyzed in detail, which included FTIR, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscope (TEM). At the same time, the comprehensive performances which included wate uptake (WR), linear expansion rate (LER), ion exchange capacities (IEC), thermal stability, chemical stability, and mechanical stability were also discussed at great length. In DD experiments, the prepared membranes demonstrated excellent acid recovery ability, with the acid dialysis coefficients (UH+) of 11×10−3 to 35.5×10−3 m/h. Furthermore, according to the test results, the prepared membranes exhibited a higher S value (35−50) than that of commercial membranes DF-120 (18.5). Therefore, the prepared membranes had competitive advantage in acid recovery via diffusion dialysis.