The decades-long and extensive global use of per- and polyfluoroalkyl substances (PFAS) has led to their widespread impact on aquatic systems. PFAS have serious adverse effects on human and environmental health. The project team recently developed a unique iron(II) sulfite (FeSO₃) material and demonstrated its reductive and oxidative properties in the degradation of PFAS. The investigations demonstrated rapid degradation of highly concentrated PFAS by the FeSO₃ material in less than 10 minutes without the need for any additional post-treatment. The three specific objectives for the project are as follows:

• Perform fundamental mechanistic studies on FeSO₃-initiated redox degradation of PFAS, identify transformation/degradation products, and elucidate reaction pathways;
• Investigate the effects of different water quality constituents present in the tested matrices on the performance of FeSO₃ redox materials for degradation of selected PFAS; and
• Assess FeSO₃ redox materials for degradation of PFAS in real groundwater, retentate water from membranes, water from ion exchange resin regeneration, and aqueous film-forming foam (AFFF)-impacted waters.

The identification of novel processes for the effective destruction of PFAS represents a significant challenge and an opportunity to develop a new understanding of the fundamental chemistry involved in the breakdown of this unique class of compounds. FeSO₃ is an innovative redox material that combines strong chemical reducing properties (due to Fe^II and SO₃^2‒) and the possibility to simultaneously produce powerful oxidative species (e.g., SO₅^•− , SO₄^•− and HO^•). The project team plans to conduct detailed kinetic and product studies of selected PFAS using high resolution mass spectrometry and advanced nuclear magnetic resonance techniques to identify the exact structures of the intermediate products in elucidation of the degradation pathways, while accounting for fluorine mass balance through total organic fluorine and total inorganic fluorine analyses. The studies include the following:

• Synthesis of novel FeSO₃ redox materials
• Characterization of materials and investigation of the performance of the technology
• Detailed investigation of the transformation byproducts of PFAS by state-of-the-art mass spectrometry
• Validation of the integrated treatment system using samples from groundwater, retentate water from membranes, water from ion exchange resin regeneration, and AFFF-impacted waters samples

The developed treatment technology is expected to achieve on-site and versatile treatment for PFAS in different water matrices and operate under ambient experimental conditions, without specialized equipment and requirements. The project will provide new scientific and transformative information crucial for implementing effective PFAS treatment in a variety of PFAS-impacted aquatic environments. Specifically, it will provide new fundamental and mechanistic understanding of a novel treatment technology applied to remediate PFAS in groundwater, retentate water from membranes, water from ion exchange resin regeneration, and AFFF-impacted waters. This research could build the foundation for ultra-efficient treatment and recycling/reuse of PFAS-impacted water using an innovative FeSO₃ redox material. The collaborative research activities will lead to the application of an innovative, cost-effective, and environmentally friendly remediation technique for the practical treatment of a variety of PFAS-impacted water matrices. (Anticipated Project Completion - 2026)