Unique fluorophilic pores engineering within porous aromatic frameworks for trace perfluorooctanoic acid removal.

Perfluorooctanoic acid (PFOA), a representative of per/polyfluorinated alkyl substances, has become a persistent water pollutant of widespread concern due to its biological toxicity and refractory property. In this work, we design and synthesize two porous aromatic frameworks (PAF) of PAF-CF and PAF-CF using fluorine-containing alkyl based monomers in tetrahedral geometry. Both PAFs exhibit nanosized pores (∼1.0 nm) of high surface areas (over 800 m g) and good fluorophilicity. Remarkable adsorption capacity (˃740 mg g) and superior efficiency (˃24 g mg h) are achieved toward the removal of PFOA with 1 μg L concentration owing to unique C-F···F-C interactions. In particular, PAF-CF and PAF-CF are able to reduce the PFOA concentration in water to 37.9 ng L and 43.3 ng L, below EPA regulations (70 ng L). The reusability and high efficiency give both PAFs a great potential for sewage treatment.