Augmenting acid recovery from different systems by novel Q-DAN anion exchange membranes via diffusion dialysis

In this study, a series of novel anion exchange membranes composed of polyvinyl alcohol (PVA) and various amount of synthesized anion exchange precursor were successfully prepared and used for acid recovery by DD process. The anion exchange precursor (Q-DAN) was synthesized through reaction of 1,5-diaminonaphthalene (DAN) and 2,3-epoxypropyltrimethylammonium chloride (EPTC) which was confirmed by proton NMR. The dosage of Q-DAN inside membrane matrix played an important role to determine the electrochemical and physicochemical properties of Q-DAN AEMs. Influences of Q-DAN and multivalent metal ions on acid recovery were elaborated in detail. Acid dialysis coefficients (U-H) values for FeCl2-HCI system were in the range of 0.0194-0.0295 m/h and separation factors were ranged from 27.84 to 52.60 at 25 degrees C. Furthermore, acid dialysis coefficient (3.28 times) and separation factor (2.84 times) were much greater than commercial membrane DF-120 (UH and S = 0.009 m/h and 18.5), respectively. Moreover, Q-DAN-4 membrane was selected to investigate the effects of multivalent metal ions on diffusion dialysis. The results showed that the presence of different metal salts in hydrochloric acid solution effect the membrane diffusivity and selectivity in diffusion dialysis process due to complexation of metal ions and acid.