Many per- and polyfluoroalkyl substances (PFAS) are strongly resistant to chemical, physical, and biological degradation. They are relatively difficult to remove from solid samples, such as soil and biosolids. Recent studies have demonstrated that PFAS laden in soil and granular activated carbon (GAC) can be degraded by means of intense heating at elevated temperatures (e.g., 700℃). Building on previous research, the project team aims to develop an innovative catalyst-assisted low-temperature treatment (LCT) method to effectively decompose PFAS present in laboratory-prepared and field-impacted solid samples, including soils, GAC, and biosolids. This limited-scope project will pursue the following four objectives:
The project team will streamline LCT for effective degradation of PFAS in AFFF and solid samples. Key parameters, including catalyst, temperature‒time profile, and solid texture will be investigated and decomposition kinetics (e.g., half-lives), thermodynamics, and pathways of PFAS with different chain lengths and functionalities will be determined. The project team will then optimize LCT processes for field samples collected from “hot spots” of PFAS and evaluate LCT for treatment and degradation of co-occurring chemicals present in AFFF and various solid matrices. Ultrahigh pressure liquid chromatography coupled with quadrupole time-of-flight mass spectrometry and gas chromatography coupled with ion trap tandem mass spectrometry will be employed to identify decomposition products of PFAS generated during LCT treatments. The yield of fluorine (F) ions from PFAS treated by LCT will be determined, and a complete F mass balance on treated matrices entering and exiting LCT will be established.
The treatment approaches (LCT) developed in this research will help to:
(Anticipated Project Completion - 2025)