Interfacial engineering in MIL-53(Al)/PEBA mixed matrix membranes for efficient n-butanol/water separation

Interfacial engineering in mixed matrix membranes (MMMs) is essential to attain superior separation performance and ensure long-term operational stability. In this research, a range of novel MMMs were designed and fabricated for pervaporation (PV) separation of n-butanol/water solution by introducing the MIL-53(Al) particles and three variants (i.e., MIL-53(Al)–NH₂, MIL-53(Al)–NO₂, MIL-53(Al)–OH) into PEBA polymer matrix. These four MIL-53(Al) counterparts were synthesized via a microwave-assisted solvothermal method by selectively functionalizing the terephthalic acid linkers with different chemical groups. The functional MIL-53(Al) variants were employed to explore the relationship between membrane microstructures and PV performance by manipulating the interfacial interactions with PEBA matrix. The findings reveal that incorporating MIL-53(Al) variants not only displayed excellent interfacial compatibility and uniform dispersion within PEBA matrix, but also constructed the preferential transport pathways for n-butanol over water molecules. Impressively, in a 1 wt% n-butanol aqueous solution at 40 °C, the resultant membrane attained a permeation flux of 1483.3 g·m^-2·h^-1 and a separation factor of 18.1. Compared to the PEBA/PVDF membrane, the total flux was enhanced by 17.1 %, and the separation factor was improved by 46.4 %. Moreover, the embedding MIL-53(Al) variants boosted thermal and mechanical properties of the membrane, endowing it with considerable potential for practical applications.