Precise identification and transport of specific molecules through framework-functionalized membranes with multiple binding sites

Abstract

Membranes with specific-recognition and superfast-filtration have significant practical applications in water purification and chiral separation. However, membrane technique still remains challenging to high selectivity and permeation in aqueous-and-organic solvents. Here, we reported a new approach to designing framework-functionalized membranes with multiple binding sites (FMMBSs) that enabled structure&size-exclusion selectivity and fast transport performance towards specific compound of shikimic acid (SA). The as-prepared FMMBSs, based on intrinsic core-shell structure of the boronate-affinity sol-gel imprinted polymers, demonstrated that exquisite control over polymerization pattern and functionalization of characteristic membrane construction played important roles in achieving fast molecule transport combined with high molecular selectivity. The superior property of the membrane-based core-shell structure had been initially demonstrated by testing nitrogen adsorption capacity, showing about a 3.0 times higher result (63.65 cm3/g) than that of original membrane (20.71 cm3/g). These framework-functionalized membranes were then regarded as the platforms to construct the FMMBSs through a first-time-developed boronate-affinity sol-gel imprinting strategy. Therefore, the FMMBSs always kept remarkably static rebinding capacity (45.48 mg g−1) and perm-selectivity factors (>10). The dynamic transport results showed that much higher SA-based rebinding capacities than that of other molecules could be still observed under pump-pressure-driven for a long time, which strongly confirmed the preparation of high-efficiency selective membrane separation system. The strategy of introducing framework-functionalized structure on porous membrane would offer a window of opportunity for preparation of high-intensitive selective separation membrane systems not only for continuous high permeability, but also for competitive selectivity.