(567c) Molecular Simulations in the Design of Novel Clay-Based Adsorbents for PFAS

Clay-based adsorbents, such as montmorillonite clay, are effective and cost-efficient materials for the removal of various toxic contaminants from water and wastewater. Thus, they comprise an excellent class of broad-acting sorbents. Per- and polyfluoroalkyl substances(PFAS) have been traced in the environment and in the human body and have been linked to various diseases including cancer. Therefore, the use of clays, which are broad-acting sorbents represents an attractive sorbent solution. In this context, our previous studies demonstrated that clays, amended with choline and carnitine could enhance PFAS sorption properties [1,2]. This paved the way for the design of novel supplement-amended clays to augment the sorption of PFAS. In this study we initially used computational techniques to screen from a pool of chemical compounds, which are either supplements or that are generally recognized as safe, and selected with the potential capacity to improve the sorbing capacity of clay for PFAS in acidic condition. A series of experimental techniques were used to investigate the sorption properties of the designed systems. Our combined computational and experimental results show that caffeine-, riboflavin- and curcumin-amended clays can, in particular instances, enhance the binding of different PFAS compared to parent (unamended) clays. Our modeling and simulation studies provide atomistic details into the PFAS molecular-recognition mechanisms of action, as well as the designed systems’ adsorption properties. Molecular simulations were used both as a design tool to identify promising amendments to the clay, as well as a means to provide atomistic insights into PFAS binding to those amended clays. Both the novel library of chemical compound-amended clays and the approach utilized could enhance the future design of novel improved amended clays and adsorbents in general.

1. Hearon SE, Orr AA, Moyer H, Wang M, Tamamis P, Phillips TD. Montmorillonite clay-based sorbents decrease the bioavailability of per- and polyfluoroalkyl substances (PFAS) from soil and their translocation to plants. Environ Res. 2022;205:112433.
2. Wang M, Orr AA, Jakubowski JM, Bird KE, Casey CM, Hearon SE, Tamamis P, Phillips TD. Enhanced adsorption of per- and polyfluoroalkyl substances (PFAS) by edible, nutrient-amended montmorillonite clays. Water Res. 2021;188:116534.