Construction of Porous Aromatic Frameworks by Organic Cage Building Blocks for Organic Vapor Adsorption and Ethanol/Water Separation

Abstract Three-dimensional porous aromatic frameworks (PAFs) possess high specific surface areas and interconnected pore channels, holding great promise for applications in adsorption and separation. To expand the library of building blocks for PAFs and enrich their topological diversity, this study employs a triangular prismatic molecular cage as a structural unit to access a PAF-331. This PAF exhibits both high porosity and framework flexibility, with a Brunauer–Emmett–Teller (BET) specific surface area reaching up to 2450 m2 g–1. The incorporation of ether oxygen linkages endows the framework with exceptional adsorption performance toward volatile organic compounds (VOCs). At 298 K, PAF-331 achieves a remarkably high benzene saturation uptake capacity of 23.54 mmol g–1 and exhibits ethanol/water separation property. Results from static adsorption measurements and mixed-gas breakthrough experiments demonstrate that PAF-331 can selectively capture ethanol vapor from dilute aqueous ethanol solutions.