Per-and poly-fluoroalkyl substances (PFAS) represent a family of emerging and persistent contaminants in water. Very few chemical and biological methods can efficiently remove them, particularly in drinking water treatment. Although adsorption with ion exchange (IX) resins is recognized as a technically effective PFAS treatment option, the processes are restricted, at a minimum, in two aspects: 1) they only transfer PFAS from one phase to another, but cannot provide an ultimate solution to detoxification; and 2) the most common off-site regeneration makes this option prohibitive. Here we propose a new approach to addressing PFAS in water through on-site regeneration of PFAS-spent IX resins with sulfate radical-based advanced oxidation processes (AOPs) or hydrated electron-driven advanced reduction processes (ARPs). Laboratory studies clearly show the destruction of sorbed PFAS and the recovery of adsorption capability of IX resins. Solution chemistry (e.g., pH), operation conditions (e.g., chemical dose), and resin material stability play a key role in the PFAS degradation and resin regeneration. The approach can purify substantial water and detoxify PFAS, while producing a small quantity of easily managed and non-hazardous regenerant primarily containing inert inorganic ions, thereby enabling a cost effective design for treatment of PFAS-polluted water. More importantly, the new approach allows SR-AOPs and ARPs, which can effectively degrade PFAS but are rarely applied to realistic drinking water treatment due to the increase in TDS, to remove PFAS from drinking water.

On-site Regeneration of PFAS-spent Ion Exchange resins with AOPs and ARPs: A new approach to PFAS pollution in water?

ACS Spring Meeting 2021

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