The objective of this proof-of-concept project is to evaluate the efficacy and sustainability of layered double hydroxide (LDH) sorbents for per- and polyfluoroalkyl substances (PFAS). LDH, also known as anionic clays, are hypothesized to effectively sorb PFAS through ion exchange or electrostatic interactions and may facilitate enhanced thermal destruction of PFAS at low temperatures. Demonstrating the use of LDH as novel sorbents during this project will introduce an efficient and sustainable alternative for treatment and management of PFAS-impacted water.

The objectives of this project will be achieved through laboratory experiments to evaluate sorption of representative long- and short-chained PFAS on novel LDH sorbents and subsequent approaches that facilitate their thermal destruction. Sorption isotherms will be developed for PFAS and candidate LDH sorbents using batch sorption experiments. Also, the thermal decomposition of PFAS sorbed to LDHs will be evaluated by examining the thermal decomposition temperatures and fluorine fate of PFAS sorbed to candidate LDH as well as AC benchmark material. Finally, the reuse of LDH-based PFAS treatment column will be evaluated by simulating sorption and treatment of simulated PFAS-impacted water.

PFAS are widely distributed in the environment and are considered among the most recalcitrant chemicals of concern requiring management today. This project will provide the Department of Defense (DoD) with improved understanding of novel LDH sorbents for long- and short-chained PFAS and subsequent thermal decomposition processes. LDH sorbents, if effective, will improve the DoD’s ability to manage groundwater containing PFAS more cost-efficiently and sustainably. Ultimately, this will allow for better protection of human and ecological well-being, while preserving the communal resources. (Anticipated Project Completion - 2024)

Kim, Hak-Hyeon, P.K. Van Groos, Y. Zhao, and A.L-T. Pham. 2024. Removal of PFAS by Hydrotalcite: Adsorption Mechanisms, Effect of Adsorbent Aging, and Thermal Regeneration. Water Research, 260: 121925. doi.org/10.1016/j.watres.2024.121925.