Evaluating the Removal of Per- and Polyfluoroalkyl Substances from Contaminated Groundwater with Different Adsorbents Using a Suspect Screening Approach

Per- and polyfluoroalkyl substances (PFASs) are ubiquitous environmental contaminants. Research has focused on technologies for the removal of perfluoroalkyl acids from water, but contaminated groundwater often contains complex mixtures of diverse groups of PFASs. We explored the potential of five adsorbents to remove mixtures of PFASs from contaminated groundwater. We used high-resolution mass spectrometry to identify 68 unique PFASs in a groundwater sample. We then performed batch experiments with activated carbon (AC), an anion exchange resin, and three different cyclodextrin polymers (CDPs) with varying surface charges to evaluate their potential to remove the 68 PFASs from the groundwater. We found that each adsorbent exhibits a different removal pattern among the 68 PFASs. AC is the most nonselective adsorbent but has relatively slow adsorption kinetics. The CDPs exhibit rapid adsorption kinetics and are more selective than AC, performing better in removing PFAS classes that are complementary to their surface charge. Analysis of the complete data set revealed that adsorption of some PFAS classes can be associated with increasing length of the perfluorinated tail, while adsorption of other classes is more strongly related to properties of the headgroup. Our study offers new insights into PFAS adsorption and a novel approach to evaluate remediation technologies for PFAS removal from groundwater.