ERASE-PFAS: Understanding and application of a new photocatalytic mechanism for PFAS degradation

University Of California-Riverside, Riverside CA

Investigators

Abstract

The accumulation of per- and polyfluoroalkyl substances (PFAS) in the environment is a significant problem that can affect human health. This project will develop a new method to degrade PFAS in water. The treatment system involves ultraviolet (UV) irradiation, a naturally occurring catalyst, and low-cost organics. The project will discover the optimal configuration of the reaction system, understand how the new system works, degrade various PFAS pollutants, and measure the products of PFAS destruction. This novel method is expected to treat a variety of PFAS in wastewater associated with water purification, environmental cleanup, and industrial wastewater management. The research findings will be applied to treat PFAS wastes by working with environmental engineering companies. Besides student training and course improvements, the education and outreach plans include developing a rapid method to detect potential PFAS exposure in daily life. This project aims to develop a novel photochemical system for PFAS destruction using a novel class of abundant and sustainable electron sources. The project will (1) investigate the working mechanisms of the new reaction system, (2) examine the system performance in degrading various PFAS, (3) characterize PFAS degradation pathways and products, and (4) evaluate and improve the system performance towards practical application. Four general technical challenges for existing PFAS degradation technologies will be addressed: (i) the destruction efficacy for various PFAS structures, (ii) the efficiency of energy and chemical utilization, (iii) the formation and control of recalcitrant residuals and byproducts, and (iv) the robustness in complex water matrices. Research approaches include (a) kinetic measurements of PFAS degradation and defluorination under variable photoreaction configurations and practical water matrices, (b) transformation product analyses using high-resolution mass spectrometry (HRMS), product isolation, nuclear magnetic resonance, and so on, (c) mechanistic elucidation using probing reagents, photolysis, and HRMS, and (d) photocatalyst capture and reuse. Compared with earlier photochemical systems (e.g., UV-sulfite and UV-iodide), the proposed new system will be transformative regarding engineering feasibility as well as the fundamental understanding of photochemical reaction mechanisms and fluorochemical degradation pathways. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.