Performance Evaluation of Novel Resins in Flow-Through Columns for PFAS Removal from Drinking Water and Treated Wastewater

Per- and polyfluoroalkyl substances (PFAS) are known bioaccumulative and persistent chemicals which pollute natural waters globally. However, there exists a lack of granular sorbents optimized to efficiently remove PFAS at environmentally relevant concentrations. To address this need, we previously developed a platform approach for fabrication of regenerable granular sorbents (i.e., ionic fluorogel (IF) resins) that selectively remove PFAS over background competing contaminants. In this project, we modified 1st generation IFs to realize structurally tunable and chemically stable resins with systematic variations of network architecture and cation density. Chemical stability was demonstrated through accelerated degradation studies. Investigation of the library of chemically stable IFs enabled insights into structure–property relationships important to high affinity PFAS binding. Results show that the chemically stable IF resin outperformed a leading commercially available ion-exchange resin in batch and column tests. Using as a guiding principle in sorbent development the cost and availability at large scale of base materials, we developed a 2nd generation IF resin based on trifunctional crosslinkers with a more translationally relevant profile in terms of chemical inputs and cost. Batch results from challenge tests with various NC waters showed that the 2nd generation IF resin had a PFAS-removal performance level intermediate between those of two leading commercial ion exchange resins. The 2nd generation IF resin had a substantially better performance in drinking water sources than in wastewater matrices. Results also showed that there is the potential to improve PFAS removal performance via optimization of the resin synthesis procedure. Additionally, because of the high modularity and copolymerization amenability of the platform chemistry used for IF synthesis, we hypothesize that future tuning of the fluorinated backbone can be used to optimize PFAS partitioning, and resin swelling and flexibility and enable superior PFAS removal across water matrices.