Thermoresponsive\nPolymer Sorbents for Efficient\nRemoval of Perfluorinated\nCompounds via Simple Heating

The efficient removal of per- and polyfluoroalkyl substances\n(PFAS)\nand recycling sorbents from contaminated water face grand challenges\nin the field of PFAS remediation. In this work, a series of thermoresponsive\nperfluoropolyether (PFPE)-containing polymer sorbents were developed\nfor efficient removal of PFAS from contaminated water using a simple\nheating process. The polymer sorbents are thermoresponsive due to\ninclusion of the monomer <i>N</i>-isopropylacrylamide (NIPAM).\nFour block copolymers with the same degree of polymerization (DP)\nof [2-(acryloyloxy)ethyl]trimethylammonium iodide (AETAI) but increasing\nDPs of NIPAM were prepared via reversible addition–fragmentation\nchain-transfer (RAFT) polymerization. The results demonstrate that\nthe balance between hydrophobic/hydrophilic segments from the polymers\nsignificantly influences their lower critical transition temperatures\n(LCSTs), and such balance could be altered by the presence of amphiphilic\nPFAS. Upon complete sorption, >99% removal for majority of the\ntested\nPFAS was achieved by heating the solution mixture to above its lower\ncritical solution temperature and filtration. The study introduces\nthe design and preparation of efficient “smart” PFAS\nsorbents based on their thermoresponsive properties, offering a new\napproach to effectively separate PFAS sorbents from treated solutions.