(321h) Advanced Adsorbents for PFAS Removal from Diverse Residual Streams

Robust and selective treatment technologies, like adsorption, must be developed to effectively remove per- and polyfluoroalkyl substances (PFAS) from diverse matrices. Conventional adsorbents, such as granulated activated carbon (GAC) and ion exchange (IX) resin, have been shown to remove PFAS but performance can suffer in complex water matrices (e.g., salinity, organic content, inorganic ions). In this work, advanced adsorbents were investigated for residual stream PFAS management at bench-scale. Five advanced adsorbents – including functionalized cyclodextrin, polymer-metal oxide hybrid, and hydrogel – were evaluated for PFAS removal from residual streams. These advanced adsorbents are scalable and tunable (e.g., adjustable functional groups) with a small treatment footprint. Real residual water streams, including reverse osmosis (RO) concentrate and scrubber water blowdown, were selected to provide complex matrices to evaluate PFAS removal. The residual streams had diverse salinities and organic content, ranging from low conductivity (< 500 µS cm^-1) and low organics (< 5 mg-C L^-1) to high conductivity (> 2000 µS cm^-1) and high organics (> 80 mg-C L^-1), to holistically evaluate adsorbents for PFAS removal.

Kinetics, isotherm, and regeneration experiments were completed with the five adsorbents in the five residual streams. Multiple PFAS, with different chain lengths and functional groups, were investigated and quantified with targeted analysis. Conventional adsorbents, including granulated activated carbon (GAC) and ion exchange (IX) resin, were also evaluated in the residual streams to provide a performance benchmark. Results show that the advanced adsorbents provide fast and near complete PFAS removal across the diverse residual streams. Moreover, multiple regeneration cycles supported sustained performance and adsorbent reuse.

Disclaimer: The views expressed in this presentation are those of the author and do not necessarily represent the views or policies of the US Environmental Protection Agency.