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-CF3 and PAF-C2F5 using fluorine-containing alkyl based monomers in tetrahedral geometry. Both PAFs exhibit nanosized pores (similar to 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 mu g L-1 concentration owing to unique C-F center dot center dot center dot F-C interactions. In particular, PAF-CF3 and PAF-C2F5 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.