ERASE PFAS: Mechanistic Investigation of PFAS Degradation using Powder Activated Carbon and Persulfate at Ambient Temperature

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The manufacturing, utilization, and disposal of perfluoroalkyl substances (PFAS) has caused widespread environmental contamination in the United States. PFAS are commonly referred to as “forever chemicals” due to their persistence, stability, and resistance to natural environmental degradation processes. In addition, PFAS tend to bioaccumulate in the human body, and mounting evidence suggests that several serious health outcomes are associated with PFAS exposure, including reduced vaccine response, increased cholesterol levels, and pregnancy complications. During the last two decades, PFAS have been increasingly detected in groundwater aquifers which serve as sources of drinking water for many communities throughout the United States. However, the treatment of PFAS contaminated groundwater can be expensive due to the extensive infrastructure and energy required to remove and destroy PFAS. The overarching goal of this project is to investigate the underlying science and engineering to advance the development and deployment of a promising low-energy and low-temperature treatment process that utilizes persulfate (PS), followed by activation with powdered activated carbon (PAC), to capture and destroy PFAS from contaminated groundwater. The successful completion of this project will benefit society through the generation of fundamental knowledge that will advance the utilization of persulfate and PAC as a cost-effective destruction technology for the treatment and remediation of PFAS contaminated groundwater. Additional benefits to society will be accomplished through education and training activities including the mentoring of one graduate student and one undergraduate student at the University of Michigan.Widespread use of PFAS in commercial products, manufacturing, and fire-fighting response has led to the contamination of soils and groundwater throughout the United States. Due to the high strength of the carbon-fluorine bond, most PFAS do not undergo natural attenuation reactions in environmental media such as biodegradation, photo-oxidation, photolysis, and hydrolysis. As a result, treatment of PFAS contaminated aquifers often requires pumping contaminated groundwater from the subsurface followed by above ground removal and disposal, which requires extensive infrastructure and/or substantial energy inputs. Few treatment technologies efficiently destroy PFAS in situ, especially at ambient temperatures. The goal of this project is to design, evaluate, and optimize a low energy and low temperature process for in situ PFAS capture and destruction from contaminated groundwater using persulfate (PS) and powdered activated carbon (PAC). The specific objectives of the research are to (1) evaluate the reaction kinetics for a homologous series of PFAS contaminants with a range of functional groups using the PS/PAC treatment process; (2) elucidate the underlying reaction mechanisms and the role of radical species in PFAS transformation and destruction during PS/PAC treatment; and (3) assess the effectiveness of the PS/PAC treatment to treat and remediate PFAS contaminated groundwater using flow-through column studies. The successful completion of this project has the potential for transformative impact through the generation of fundamental knowledge that will advance the utilization of persulfate and powdered activated carbon as an efficient and cost-effective destruction technology for in situ treatment of PFAS-impacted groundwater. To implement the educational and outreach goals of this project, the Principal Investigator (PI) plans to recruit and mentor students from underrepresented backgrounds to work on the proposed research. In addition, the PI will develop an interactive instructional module, “Understanding PFAS and Exposure Prevention,” for K-12 students to present in communities where PFAS has been detected in drinking water.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.