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

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 FeCl 2 ). 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 ( ) 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 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.