Superfund Research Program
Remediation of Perfluorinated Chemicals in Water Using Novel High-Affinity Polymer Adsorbents
Project Leader: Gokhan Barin
Grant Number: R44ES029401
Funding Period: Phase II: August 2019 - August 2021
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The pervasive contamination of drinking water resources by toxic per- and polyfluorinated alkyl substances (PFAS), such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), has emerged as a major health crisis affecting millions of people across the U.S. Given the environmental persistence of these contaminants and their established linkage to serious health risks, it is imperative that safe, efficient, and cost-effective PFAS remediation technologies be developed that can eliminate these contaminants from U.S. water supplies. While PFOA and PFOS have been two of the most widely studied PFAS, twelve other PFAS have also been measured in the blood serum of Americans over the age of twelve. Currently, the U.S. Environmental Protection Agency has a non-enforceable Lifetime Health Advisory guideline of 70 parts per trillion (ppt), which applies only to the combination of PFOA and PFOS. However, faced with growing pressure to address PFAS contamination, numerous states have acted to address the PFAS crisis, proposing limits as low as 10 ppt of individual PFAS and for a broader class of PFAS.
Although different technologies have been explored for remediation of PFAS-contaminated water, adsorption-based methods using activated carbon or ion-exchange resins remain the most widely used approach. These adsorbents also have well-demonstrated shortcomings, such as significant fouling by natural organic matter and/or other water matrix constituents and energy-intensive or difficult regeneration process that limits their reusability and lifetime. CycloPure is developing a novel class of cyclodextrin-based polymer adsorbents with high affinity for PFAS in order to address the urgent need for a highly scalable, cost-effective method to eliminate PFAS from drinking water supplies.
During the Phase I period, a promising approach was identified for the development of cyclodextrin polymers (branded as DEXSORB+) effective against a broad range of PFAS that combines both electrostatic and hydrophobic interactions in a uniquely designed structure. During Phase II, the research team continues their efforts to develop and optimize DEXSORB+ polymers with fast uptake kinetics and high adsorption capacities for PFAS and investigate and understand groundwater matrix effects systematically on PFAS adsorption performance and the ability to regenerate the adsorbent. They are also dedicating efforts to develop strategies for particle size control and then perform small-scale column testing in order to simulate a full-scale treatment process. These activities will provide them with guidance on the operational conditions prior to moving onto pilot-scale studies.