(245e) Investigation into Cationic Surfactant and Polyelectrolyte Coated ?-Zeolites for Rapid and High-Capacity Adsorption of Short- and Long-Chain Pfas

Per- and polyfluoroalkyl substances (PFAS) have been implicated as carcinogens and have emerged as contaminants of serious health and safety concerns. The objective of this work is to investigate the potential use of β-zeolites for the efficient and rapid removal of short- and long-chain PFAS from water. PFAS adsorption capacities of β-zeolites (CP811C and CP814E) with varying silica and alumina (Si/Al) ratios were evaluated. The zeolites were coated with either (cetyltrimethylammonium bromide - CTAB) or (poly(diallyldimethylammonium chloride) - PDADMAC) to enhance adsorbent affinity for highly soluble PFAS. Perfluorooctanoic acid (PFOA) and heptafluorobutyric acid (PFBA) were selected as model solutes, representing long- and short-chain PFAS, respectively, and were adsorbed onto unmodified and modified β-zeolites in ambient conditions. Characterization via scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and zeta potential analysis showed successful surface modification. All studied β-zeolites rapidly adsorbed PFAS, reaching equilibrium within 1-2 hours. Among them β-zeolite CP811C was found to have higher PFOA uptake than CP814E (91.87 vs. 57.77 mg/g). However, CTAB coatings reduced PFOA adsorption capacity on β-zeolites by up to 58.7%. Similarly, PDADMAC coating also reduced PFOA adsorption capacity by up to 15.4%, but increased PFBA adsorption capacity by up to 51.3%. Such batch adsorption kinetics data was well-described by the pseudo-second order (PSSO) rate model. Additionally, PFOA and PFBA adsorption equilibrium onto β-zeolite CP811C was fitted by the Langmuir isotherm model, with maximum adsorption capacity of 181.87 and 27.89 mg/g respectively. Such faster adsorption rates and higher adsorption capacities make β-zeolites promising for PFAS remediation compared to conventional Granular activated carbon and ion exchange resins PFAS adsorbents.