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

Abstract

Per- and polyfluoroalkyl substances (PFASs) are aqueous contaminants associated with serious health consequences. Conventional PFAS adsorbents are limited by slow kinetics and low short-chain PFAS uptake, driving interest in high-performing alternatives. Here, β-zeolites were investigated for short- (<C8) and long-chain (≥C8) PFAS removal. β-zeolites with high (CP811C) and low (CP814E) silica/alumina ratios were coated with cetyltrimethylammonium bromide (CTAB) or poly(diallyldimethylammonium chloride) (PDADMAC) to enhance short- and long-chain PFAS retention, represented by heptafluorobutyric acid (PFBA) and perfluorooctanoic acid (PFOA). PFAS rapidly adsorbed onto β-zeolites, reaching equilibrium within 1–2 h. Greater PFOA uptake (91.87 vs 57.77 mg/g) was reported onto the silica-rich β-zeolite, CP811C. While the CTAB coatings reduced PFOA adsorption capacity by 58.7%, the PDADMAC coatings increased PFBA adsorption capacity by 51.3%. On unmodified CP811C, PFOA and PFBA exhibited maximum adsorption capacities of 181.87 and 27.89 mg/g, respectively. Fast and high-capacity adsorption make β-zeolites highly promising PFAS adsorption technology.