Prepared poly(aryl piperidinium) anion exchange membranes for acid recovery to improve dialysis coefficients and selectivity

The diffusion dialysis (DD) process based on AEM is considered for the acid recovery from acid effluents. In this work, the novel self-organized nanostructured cross-linked AEMs based on poly (aryl piperidinium) are synthesized for acid recovery. The cross-linked AEMs are designed by introducing 2-bromoethanol and 1,6-dibromohexane into the hydrophobic poly (biphenyl piperidine)s backbone via Menshutkin reaction, and the self-assembled nanostructure is confirmed by TEM imagines. The acid flux is improved by constructing a micro-phase separation structure and hydrogen bond network. The H-bond networks and cross-linking structure improve the selectivity between the acid and salt system without sacrificing IEC values of AEM. The IEC values of PBP-OH-x AEMs are in the range of 2.18–2.21 mmol/g. The AEMs exhibit high H+ dialysis coefficients (UH), ranging from 0.045 to 0.053 m/h, and have good separation factors (S) in the range of 32–56. The prepared PBP-OH-x AEMs have better DD performance, comparing with the commercial membrane DF-120 (UH = 0.009 m/h, S = 18.5). The novel AEMs based on poly (aryl piperidinium) showed the potential to be used in acid recovery via DD.