Influence of 2,2′,6,6′‐tetramethyl biphenol‐based anion‐exchange membranes on the diffusion dialysis of hydrochloride acid

ABSTRACT Quaternary ammonium functionalized poly(arylene ether) (QPAE‐Br) membranes based on 2,2′,6,6′‐tetramethyl biphenol for diffusion dialysis (DD) were designed and successfully fabricated via nucleophilic substitution polycondensation, bromination, film casting, and quaternization. The structures, thicknesses, ion‐exchange capacities (IECs), water uptakes, swelling ratios, ion conductivities, and mechanical properties of QPAE‐Br were used to characterize the membranes. The influence of the membrane structures on the DD performances was investigated by DD tests of simulated industrial pickling wastewater (1 mol/L HCl, 0.1 mol/L FeCl2). The DD results show QPAE‐a (IEC = 1.51 mmol/g) as the best DD candidate. Predialysis treatments further improved the DD performances of QPAE‐Br. QPAE‐a exhibited an excellent proton diffusion coefficient ( UH+) of 0.033 m/h and a high separation factor (S) of 95.45 after the predialysis treatment at room temperature; these values were much higher than those of the commercial DF‐120B membrane (0.004 m/h for UH+ and 24.3 for S at 25 °C) and other reported DD membranes. QPAE‐a has great potential for acid recovery via DD. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45333.