Aramid nanofiber gel skeleton induced MOFs 3D long-range quasi-continuous distribution in MMMs for enhanced n-butanol permselective pervaporation

High-performance mixed-matrix membranes (MMMs) featuring with superior permselectivity and easy processability are highly demanded toward the effective pervaporation recovery of bio-alcohols, however their development still remains a huge challenge. In this work, a self-standing and exceptional zeolitic imidazolate framework (ZIF-8)@Aramid nanofiber/Polydimethylsiloxane (Z@A/P) MMM was constructed via an ingenious “three-dimensional (3D) connecting MOFs pre-forming & polymer backfilling” coupling strategy. The preformed hybrid aerogel network (ZIF-8@Aramid nanofiber) not only exhibited a desirable interfacial compatibility with PDMS but also facilitated ZIF-8 particles to form interconnected 3D long-range consecutive MOF phases across the MMM. Moreover, benefiting from the combination of highly permeable and selective molecular inner channels of ZIF-8 nanoparticles along with their formed continuous and fast transport pathways deriving from the long-range connected assembly phases, the pervaporation performance of the resulting MMMs was greatly enhanced compared to that of physical blending-obtained MMM counterpart. Particularly, an excellent total flux of 935 g m −2  h −1 along with a high separation factor of 19.6 was achieved for the optimized Z@A/P4 MMM even with a relatively low loading of 4.9 wt% for pervaporation recovery of n -butanol from its 1.5 wt% aqueous solution. Therefore, this novel fabrication strategy opens up a new avenue to achieve the high-performance MMMs with the 3D interconnected long-range consecutive MOF phases across the membrane toward the efficient bio-alcohols recovery and other related fields.