Superfund Research Program
Remediation of Perfluorinated Chemicals in Water Using Novel High-Affinity Polymer Adsorbents
Project Leader: Gokhan Barin
Grant Number: R43ES029401
Funding Period: Phase I: March 2018 - September 2018
Per- and polyfluoroalkyl substances (PFASs) are a highly toxic class of micropollutants harming water supplies in communities across the country. PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonate) are the most prevalent PFASs. Elevated concentrations of PFASs exist in drinking water across the country, especially near industrial sites, military airbases, and wastewater treatment plants. Monitoring data indicates that drinking water of up to 50 million Americans is likely contaminated by PFASs. PFASs have been shown to cause multiple cancers, thyroid disease and developmental disorders at parts per trillion (ppt) concentrations. These chemicals accumulate and remain in the body for years. Blood levels rise by 25 percent with every 10 ppt increase in PFAS concentration.
Drinking water is a major source of PFAS exposure. Infants and newborns are vulnerable to the effects of these chemicals, which are passed during pregnancy and through breast milk. In May 2016, the U.S. Environmental Protection Agency (EPA) lowered its PFAS health advisory from 400 ppt to 70 ppt. Over the past several years, numerous communities have been forced to shut down drinking water sources due to harmful levels of contamination. Recognizing the substantial health risks caused by PFASs, States across the country are adopting even more stringent limits, i.e. some as much as 5 times lower than EPA levels.
CycloPure is developing novel polymers for the remediation of PFASs from contaminated water resources. These polymers are obtained from cyclodextrins, which are derived from corn starch, and synthesized in one step using commercially available crosslinkers in a cost-effective way. Cyclodextrins feature a cup-like shape with a cavity that can bind PFASs strongly and selectively in water. Leveraging these specific interactions at the molecular level, adsorption properties of CycloPure’s polymers can be fine-tuned easily for the removal of PFASs for either point-of-use applications or large-scale treatment systems.
During the Phase I period, CycloPure was able to identify cyclodextrin-based materials that can remove both PFOA and PFOS effectively and are suitable for large-scale manufacture. Their approach relies on the discovery of new chemistries that afforded materials with enhanced affinity and uptake kinetics for PFOA and PFOS. They achieved this performance improvement through the introduction of secondary interaction sites—primary sites being cyclodextrins—into polymers. These new polymers can remove more than 95 percent of PFOA and PFOS from an initial concentration of as low as 500 ppt in only 30 minutes.
Furthermore, they demonstrated that these materials are highly effective in the removal of other short- and long-chain PFASs that are also of significant concern. CycloPure’s ultimate goal is to make water safe by developing commercially viable processes for the sequestration of PFASs using sustainable resources. Demonstrating the technical feasibility of their approach in this Phase I project, they continue to focus their efforts on further research and development activities to develop water treatment technologies for consumer, industrial, and municipal uses.