Swelling mechanism of PEBA-2533 membrane for pervaporation separation of high boiling point organic compounds: Experiment and molecular dynamics simulation

摘要

High boiling point organic compounds (HBOCs) with aromaticity can be recovered by poly(ether block amide) (PEBA-2533) membrane from dilute aqueous solutions as the products with high-purity using a pervaporation-fractional condensation (PVFC) coupling system. The swelling mechanism of the PEBA-2533 membrane is the decisive factor for the separation and recovery of HBOCs, however, it has not yet been clearly understood. In this study, the swelling behaviors of PEBA-2533 membrane in phenol, aniline, and furfural aqueous solutions were investigated by experiments and molecular dynamics (MD) simulation. The effect of the non-bond interaction energy and the number of hydrogen bonds between water and HBOC molecules on the swelling degree of PEBA2533 was analyzed. The results show that the number of hydrogen bonds should be the dominant factor to determine the swelling degree of membrane. Furthermore, the structures of phenol, aniline and furfural were evaluated for their abilities to form hydrogen bonds through the molecular electrostatic potential (MESP) analysis. Besides, by investigating the feed-membrane surface affinity, it is found that the absorption concentration was related to the proportion of organic compound on the membrane surface. Based on the MD simulation results, the swelling mechanism of PEBA-2533 in dilute aqueous solutions was proposed and illustrated, which provided a way to promote the industrialization of PV technology.