Enhanced gas separation performance of mixed matrix hollow fiber membranes containing post-functionalized S-MIL-53

Abstract

Mixed matrix hollow fiber membranes (MMHFMs) filled with metal-organic frameworks (MOFs) have great potential for energy-efficient gas separation processes, but the major hurdle is polymer/MOFs interfacial defects and membrane plasticization. Herein, lab-synthesized MIL-53 was post-functionalized by aminosilane grafting and subsequently incorporated into Ultem®1000 polymer matrix to fabricate high performance MMHFMs. SEM, DLS, XRD and TGA were performed to characterize silane-modified MIL-53 (S-MIL-53) and prepared MMHFMs. Moreover, the effect of MOFs loading was systematically investigated first; then gas separation performance of MMHFMs for pure and mixed gas was evaluated under different pressures. MMHFMs containing post-functionalized S-MIL-53 achieved remarkable gas permeation properties which was better than model predictions. Compared to pure HFMs, CO2 permeance of MMHFM loaded with 15% S-MIL-53 increased by 157% accompanying with 40% increase for CO2/N2 selectivity, which outperformed the MMHFM filled with naked MIL-53. The pure and mixed gas permeation measurements with elevated feed pressure indicated that incorporation of S-MIL-53 also increased the resistance against CO2 plasticization. This work reveals that post-modified MOFs embedded in MMHFMs facilitate the improvement of gas separation performance and suppression of membrane plasticization.