Significant efforts have been undertaken to remediate groundwater sources impacted with per- and polyfluoroalkyl substances (PFAS) using destructive and non-destructive technologies. Adsorption technologies have proven effective in controlling the occurrence of PFAS in impacted groundwater wells; however, media exhaustion will occur, necessitating disposal or regeneration.

The primary objective of this research is to investigate the in situ regeneration of PFAS-laden adsorbents and simultaneous PFAS destruction using an innovative in situ electro-regeneration and destruction approach. The specific objectives are to investigate how PFAS carbon-chain length and structure, carbon-based adsorbent properties, and water matrix characteristics affect PFAS-laden carbon-based adsorbent electro-regeneration. The simultaneous destruction of PFAS during the electro-regeneration of the spent media also will be examined.

This project will use a bench-scale electrified technology to regenerate PFAS-laden carbon-based adsorbents. Co-existing electrooxidation may enable simultaneous PFAS destruction. The technology’s working principle relies on using exhausted media as the cathode and completing the circuit with an anode. An up-flow mode, rapid, small-scale column reactor will be utilized to fix the carbon media. This new electrified regeneration approach will result in the electrostatic repulsion of PFAS molecules from the exhausted media, while simultaneously destroying PFAS molecules on the anode. The research will be divided into four major tasks.

• Bench scale adsorption and regeneration experiments will be performed for selected carboxylated and sulfonated PFAS, with varying molecular properties including carbon chain lengths (C4-C14), molecular weights, and acidity constants (pKa).
• Activated carbon adsorbents with different physicochemical properties, such as surface area, pore volume, conductivity, and chemical characteristics, will be investigated for their adsorption and electro-regeneration efficiencies.
• The impact of background water quality characteristics on electro-regeneration will be investigated using simulated waters, with hydrophobic and hydrophilic characteristics, and real groundwater samples.
• The simultaneous destruction of PFAS during the electro-regeneration of spent adsorbent will be evaluated for different anode materials, such as titanium, and boron-doped diamond.

The results of this research will enhance the understanding of the parameters that play a vital role in the effectiveness of the newly developed electrified regeneration technology, allowing for the simultaneous electro-regeneration of PFAS-laden carbon-based adsorbents and the in situ destruction of PFAS. The knowledge gained during this research will be valuable for the broader scientific community and the DoD. The successful execution of this research will provide a new technology for ongoing impacted site cleanup efforts, ultimately protecting the warfighter and installation communities. (Anticipated Project Completion - 2026)