Preparation of diffusion dialysis membrane for acid recovery via a phase-inversion method

Herein, the preparation of anion exchange membrane (AEM) from brominated poly(2,6-dimethyl 1,6-phenylene oxide) BPPO and dimethylaniline (DMA) by phase-inversion process is reported. Anion exchange membranes (AEMs) are prepared by varying the DMA contents. Prepared AEMs show high thermal stability, water uptake (WR) around 202% to 226%, dimensional change ratios of 1.5% to 2.6% and ion exchange capacities (IECs) of 0.34 mmol/g to 0.82 mmol/g with contact angle of 59.18&#176; to 65.15&#176;. These membranes are porous in nature as confirmed by SEM observation. The porous property of membranes are important as it could reduce the resistance of transportation of ions across the membranes. They have been used in diffusion dialysis (DD) process for recovery of hydrochloric acid (HCl) from the mixture of HCl and ferrous chloride (FeCl<SUB>2</SUB>). Presence of &#175;N+(CH<SUB>3</SUB>)<SUB>2</SUB>C<SUB>6</SUB>H<SUB>5</SUB>Br<SUP> &$175;</SUP>as a functional group in membrane matrix facilitates its applications in DD process. The dialysis coefficients of hydrochloric acid (<I>U<SUB>H</SUB></I>) of the membranes are in range of 0.0016 m/h to 0.14 m/h and the separation factors (<I>S</I>) are in range of 2.09 to 7.32 in the HCl/FeCl<SUB>2</SUB> system at room temperature. The porous membrane structure and presence of amine functional group are responsible for the mechanism of diffusion dialysis (DD).