Porous Pillar[5]arene-Based Polymers for Efficient Removal of Perfluorinated Pollutants from Aqueous Phases

Abstract

Per-and polyfluorinated alkyl substances (PFAS) are deemed as a class of persistent pollutants with chemical toxicities, which cause severe contamination to air, soil, and water resources. Advanced depuration materials with effective adsorption potency are urgently needed to address these emerging environmental and health issues. Herein, porous pillar[5]arene-based polymers (P-P5APs) were easily prepared via a one-step crosslinking reaction between perhydroxylated pillar[5]arene and decafluorobiphenyl, as a supramolecular adsorbent for PFAS. A water-soluble pillar[5]arene derivative was chosen as the model host to prove that such a macrocycle could encapsulate perfluorobutanesulfonic acid with an association constant of 10 5 M −1 . Nitrogen adsorption tests demonstrated that the resultant porous material containing the pillar[5]arene scaffold possessed a satisfactory surface area (S BET = 539.68 m 2 •g −1 ) and pore diameter (3.82 nm). Compared with commercially available activated carbon, P-P5APs exhibited superior adsorption efficiency toward eight representative PFAS from the aqueous phase, mainly ascribed to nonspecific adsorption by the pore structure of the cross-linked material coupled with multiple intermolecular binding sites of the macrocyclic scaffold. Moreover, this supramolecular absorbent was recyclable and could be reused 5 times with no obvious loss of performance.