DFT-based First-Principle Investigation on Tailoring Adsorbent Surfaces for Effective PFAS Removal

Removal of PFAS, per- and polyfluoroalkyl substances, is a chief societal challenge due to their complex molecular behavior and high stability. While adsorption is the most widely studied PFAS removal technique, a lack of fundamental understanding of factors governing PFAS adsorption in the natural environment significantly hindered the development of effective and efficient PFAS adsorbents. Addressing these hurdles, we utilize Density Functional Theory (DFT) calculations to uncover the chemical physics behind the behavior of PFAS adsorption onto a single-metal atom catalyst on a biochar support. Through the systematic evaluation of the electronic structure of the adsorbent, especially the metal coordination system (M-N₄), we investigated their impact on the adsorbent surface properties, which directly affect the effectiveness of the PFAS adsorption. Our results showed that different transitional metals and their valence states had an appreciable impact on the charge and electron distribution of the adsorbent surface, PFAS interactions, and molecular orientations, which aligns with the corresponding experimental results. In this talk, we will present the results of DFT calculations in determining the optimal structural characteristics for effective adsorbent to remove both short- and long-chain PFAS molecules, showcasing the significant impact of DFT investigation in understanding the electronic structure, properties, and interactions between the adsorbate and the adsorbent.