Unique fluorophilic pores engineering within porous aromatic frameworks for trace perfluorooctanoic acid removal
Chi Zhang, Junchao Dong, Panpan Zhang, Lei Sun, Yang Liu, Wenjian Wang, Xiaoqin Zou, Yunning Chen, Qingkun Shang, Danyang Feng, Guangshan Zhu
Abstract
ABSTRACT 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 (∼1.0 nm) of high surface areas (over 800 m2 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-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.