Covalent organic framework membranes engineered by bioinspired imidazole channels for ultrafast nanofiltration

Covalent organic framework membranes featuring uniform nanopores are ideal candidates for molecular sieving. However, the trade-off between permeability and selectivity should be appropriately solved. Herein, we propose a pore-environment engineering strategy by covalently anchoring histamines into the confined pores of COF-316. The introduced imidazoles function as hydrogen bond acceptors, forming dynamic hydrogen-bonding networks that facilitate selective water transport. Such modification significantly enhances the hydrophilicity of the pore interior and reduces the activation energy barrier for water permeation. As a result, the optimized COF-316H membrane achieves a remarkable water permeance of 319.2 L m −2  h −1 bar −1 , a nearly threefold enhancement over the pristine COF-316 membrane, while maintaining a dye rejection exceeding 99%. Furthermore, the membrane exhibits excellent long-term stability and reversible antifouling property. This work offers a promising avenue to overcoming the permeability-selectivity trade-off through precise engineering of confined pore environment in advanced separation membranes.