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(3) and PAF-C(2)F(5) using fluorine-containing alkyl based monomers in tetrahedral geometry. Both PAFs exhibit nanosized pores (∼1.0 nm) of high surface areas (over 800 m(2) g(−1)) and good fluorophilicity. Remarkable adsorption capacity (˃740 mg g(−1)) and superior efficiency (˃24 g mg(−1) h(−1)) are achieved toward the removal of PFOA with 1 μg L(−1) concentration owing to unique C–F···F–C interactions. In particular, PAF-CF(3) and PAF-C(2)F(5) are able to reduce the PFOA concentration in water to 37.9 ng L(−1) and 43.3 ng L(−1), below EPA regulations (70 ng L(−1)). The reusability and high efficiency give both PAFs a great potential for sewage treatment.