A Porous Aromatic Framework Constructed from Benzene Rings Has a High Adsorption Capacity for Perfluorooctane Sulfonate

A low-cost and easily constructed porous aromatic framework (PAF-45) was successfully prepared using the Scholl reaction. PAF-45 was, for the first time, used to remove perfluorooctane sulfonate (PFOS) from aqueous solution. Systematic experiments were performed to determine the adsorption capacity of PAF-45 for PFOS and to characterize the kinetics of the adsorption process. The adsorption of PFOS onto PAF-45 reached equilibrium in 30 min and the adsorption capacity of PAF-45 for PFOS was excellent (5847 mg g −1 at pH 3). The amount of PFOS adsorbed by PAF-45 increased significantly as the cation (Na + , Mg 2+ , or Fe 3+ ) concentration increased, which probably occurred because the cations enhanced the interactions between the negatively charged PFOS molecules and the positively charged PAF-45 surface. The cations Na + , Mg 2+ and Fe 3+ were found to form complexes with PFOS anions in solution. Density functional theory was used to identify the interactions between PFOS and Na + , Mg 2+ and Fe 3+ . We expect that materials of the same type as PAF-45 could be useful adsorbents for removing organic pollutants from industrial wastewater and contaminated surface water.