Superfund Research Program
Filtration Media for In-Home PFAS Removal from Drinking Water
Project Leader: Steven D. Dietz
Grant Number: R43ES032735
Funding Period: Phase I: February 2021 - January 2023
Per- and polyfluoroalkyl substances (PFAS), also commonly known as perfluorinated compounds, are a large family of man-made, globally distributed chemicals that have been used for decades. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are the most common PFAS, but thousands of other derivatives exist. PFAS have been widely used in consumer products such as non-stick cookware (Teflon®), carpets and carpet treatment products (Scotchgard®), food packaging, aqueous firefighting foams, hydraulic aviation fuels and in the aerospace, automotive, construction, and electronics industries. PFAS are emerging environmental pollutants in groundwater, and they are attracting significant attention due to their global distribution, persistence, toxicity and tendency to bio-accumulate. PFAS contamination has been found in more than 1400 locations in 49 states and the EPA estimates that the drinking water of more than 110 million Americans may already be contaminated. Once released into the environment, they are not easily broken down by air, water, or sunlight. Thus, people can be exposed to PFAS that were manufactured months or years in the past. PFAS can travel long distances in the air and water, exposing people to PFAS manufactured or emitted from facilities many miles away. Human exposure can also occur through contact with products containing PFAS. In 2016, EPA established a lifetime health advisory (LHA) level of 70 parts per trillion (ppt) for individual or combined concentrations of PFAS in drinking water and many states are establishing even lower levels. Epidemiological studies have shown that the occurrence of PFAS in humans is probably linked to a high incidence of thyroid disease, high cholesterol, ulcerative colitis, kidney cancer, testicular cancer, and pregnancy-induced hypertension. Current water treatment technologies that can meet the EPA targets are not cost effective, especially for in-home use, necessitating a need for technology/advanced materials to cleanup drinking water that are efficient, cost effective and can meet the EPA target of 70 ppt or lower. The research team is developing an adsorption-based system for removing PFAS from drinking water down to EPA prescribed limits of 70 ppt (parts per trillion) or lower. The key to such a system is a low cost, high capacity adsorbent with fast kinetics to remove PFAS. The researcher's sorbent uses a mesoporous carbon structure grafted with Lewis base functionalized groups to remove PFAS via physical adsorption. The mesopores provides very fast adsorption kinetics and accessibility to the functionalized adsorption sites. The strength of the Lewis acid-base interaction can be tuned to allow the sorbent to be effective even in the presence of the multiple contaminants found in drinking water. The fast adsorption and high PFAS capacity of the sorbent will reduce the system size and enable their use in smaller home-based systems.