Anion exchange membranes with efficient acid recovery obtained by quaternized poly epichlorohydrin and polyvinyl alcohol during diffusion dialysis

Herein, we discussed the synthesis of quaternized poly epichlorohydrin (QPECH) by the reaction of poly epichlorohydrin (PECH) with N, N-dimethylethanolamine (DMEA). After that, different amounts of QPECH were mixed with the polyvinyl alcohol (PVA) and tetraethyl silicate (TEOS) to fabricate a series of anion exchange membranes (AEMs) by sol-gel reaction. The chemical structure of the synthesized QPECH was effectively proved by Fourier transform infrared (FTIR) and 1 H NMR. Hereafter, the composite membrane structure was determined by FT-IR, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), and the physical and chemical properties such as thermogravimetric analysis (TGA), water uptake (W R ), ion exchange capacity (IEC), linear expansion rate (LER) and diffusion dialysis (DD) were tested. The performance, such as acid recovery and selectivity of PVA/QPECH composite membranes with different QPECH content, was discussed comprehensively. The results showed that the W R of the composite membrane was 82.35–158.54%, the LER was 19.23–40.74%, and the IEC was from 0.64 to 1.76 mmol/g. In the DD test simulating waste acid recovery, the acid dialysis coefficient (U H + ) was in the range of 11.1–30.0*10 -3  m/h, and the separation factor (S) was 24.79–42.24. The U H + and S of the composite membranes were all better than that of commercial membrane DF-120. In conclusion, this study demonstrated that the application of anion exchange membrane based on PVA/QPECH had the potential in acid recovery by DD method.