Thermally Driven Separation of Perfluoroalkyl Substances with High Efficiency

Perfluoroalkyl substances (PFASs), such as perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), can contaminate the surface and groundwater. Common treatment strategies and adsorbents have low adsorption efficiencies and poor selectivity toward PFASs because of the extremely low surface energy of these compounds. This paper reports the use of a phenolic resin (PR) modified with perfluoroalkyl (PFA) segments and thermally sensitive poly(ethylene glycol) (PEG) segments (PR-PEG-PFA) to remove PFOA and PFOS from water. The modified PR microspheres captured >90% of PFASs and were insensitive to common anionic surfactants. By treating simulated wastewater six times with this material, the PFOA concentration in water was reduced from 1 ppm to 43 ppt (43 ng L^-1), showing that PR-PEG-PFA is a promising adsorbent for PFAS separation, recovery, and recycling.