Per- and Polyfluoroalkylated substances (PFAS) have been a pervasive contaminant globally since the mid- 21st century. Exposure to PFAS has been known to cause significant health problems, including but not limited to birth defects, hormonal issues, cancers, and infertility. Due to the nature of the strong fluorine-carbon bonds in the tails of PFAS molecules, PFAS particles do not readily break down in the environment. Thus, it is necessary to remove them from environments. Adsorption-based PFAS removal has recently attracted significant attention, due to its merits such as easy operation, cost-effectiveness, and facile scalability to industrial scale. Zeolite, nanoporous aluminosilicates, shows great potential as an adsorbent for PFAS in water due to its wide variety of nanopore sizes, strong attraction between zeolites’ pores and PFAS, and commercial availability. PFAS molecules have a hydrophilic carbocyclic acid head and a hydrophobic fluoroalkylated long-chain tail; however, the adsorptive impact of hydrophobicity of adsorbents remains unclear. In this study, thus, we aim to elucidate the effects of adsorbents’ hydrophobicity on PFAS aqueous removal using zeolites with tailored hydrophobicity. With this end, zeolite Beta with different degrees of hydrophobicity was synthesized to adsorb Perfluorooctanoic acid (PFOA), one of the largest classes of PFAS. The degree of hydrophobicity of zeolite Beta was determined by water vapor adsorption experiments. The prepared zeolite adsorbents were subjected to aqueous PFOA adsorption at room temperature in batch testing, followed by liquid chromatography-mass spectrometry (LC-MS) analysis. As a result, PFOA adsorption rates of zeolite Beta samples were significantly increased with increasing their hydrophobicity. These findings will guide us in developing effective zeolite adsorbents for aqueous PFAS removal
