Membrane adsorbers with ultrahigh metal–organic framework loading for high flux selective separations to isomer

Abstract

Membrane-based separation processes have received significant attention as promising schemes realizing energy-efficiency micro-molecule separation. However, traditional Mixed Matrix Membranes (MMMs) inevitably faced the restriction that of low-level substrate-polymer interfacial consistency, functional loaders agglomeration, instability under long-term reaction and so on, causing it extremely challengeable to construct high-performance membrane-based separation system. Here, incorporating ideas of mussel biomimetic chemistry, a 3D nano-hybrid seeding strategy was designed for in situ assembling nanosized zeolitic imidazolate frameworks (ZIFs) to polydopamine-adhesive nanofibers, followed by the construction of specific imprinting sites within nanofiber membranes driven by boron-affinity sol–gel strategy, which achieved high-efficiency selective separation to shikimic acid (SA) with great medicinal value. This strategy simultaneously improved permeability and selectivity of separation membrane to nanoscale molecules. And superior SA affinity stability was maintained with the ultrahigh ZIF-8 loadings (73 %) even during long-term cyclic tests, where only less than 10.09 % of rebinding selective capacity loss and 6.50% of perm-selectivity damage existed. In addition, the antifouling durability as well as antibacterial persistence were obtained due to ZIF-8-functionalized polydopamine (PDA)-connected nanofibers construction. This symbiosis-inspired de novo strategy could promisingly draw bright blueprint for burgeoning MMMs to realize specifical separation of molecules with medical value against isomer mixture.