Sustainable recovery of perfluoroalkyl acids using a reusable molecular cage

Perfluoroalkyl acids (PFAAs) are widely used surfactants valued for their unique physicochemical properties; however, their environmental persistence and high production costs present major challenges. Current approaches predominantly focus on remediation, with efficient recovery strategies remaining underdeveloped. Here, we introduce a simple and sustainable method for PFAA recovery using a water-soluble organic molecular cage. Each cage molecule selectively induces the precipitation of approximately 19 PFAA molecules from complex media. Owing to the exceptional stability of the cage, both the cage and the PFAAs can be fully regenerated via a low-energy, solvent-free acid treatment. The cage is synthesized through a scalable, chromatography-free process and supports a closed-loop recovery cycle. Recovery efficiency remains high across three cycles, with 94% of PFOA recovered by mass balance, confirming the robustness and practicality of the system. This strategy offers a cost-effective and environmentally responsible solution, simultaneously addressing PFAA contamination and resource recovery.