Investigation into Cationic Surfactants and Polyelectrolyte-Coated -Zeolites for Rapid and High-Capacity Adsorption of Short- and Long-Chain PFAS

Per- and polyfluoroalkyl substances (PFASs) are aqueouscontaminantsassociated with serious health consequences. Conventional PFAS adsorbentsare limited by slow kinetics and low short-chain PFAS uptake, drivinginterest in high-performing alternatives. Here, beta-zeolites wereinvestigated for short- (= C8) PFASremoval. beta-zeolites with high (CP811C) and low (CP814E) silica/aluminaratios were coated with cetyltrimethylammonium bromide (CTAB) or poly-(diallyldimethylammoniumchloride) (PDADMAC) to enhance short- and long-chain PFAS retention,represented by heptafluorobutyric acid (PFBA) and perfluorooctanoicacid (PFOA). PFAS rapidly adsorbed onto beta-zeolites, reachingequilibrium within 1-2 h. Greater PFOA uptake (91.87 vs 57.77mg/g) was reported onto the silica-rich beta-zeolite, CP811C. Whilethe CTAB coatings reduced PFOA adsorption capacity by 58.7%, the PDADMACcoatings increased PFBA adsorption capacity by 51.3%. On unmodifiedCP811C, PFOA and PFBA exhibited maximum adsorption capacities of 181.87and 27.89 mg/g, respectively. Fast and high-capacity adsorption make beta-zeolites highly promising PFAS adsorption technology.