Perfluoroalkyl substances (PFAS) are an emerging class of environmental contaminants. High capacity adsorbents which can selectively remove mixtures of both long-chain and short-chain PFASs from natural waters are needed. Swellable organically modified silica (SOMS) is a hydrophobic porous adsorbent that reversibly swells 3-times in volume upon addition of organic liquids. A PFAS-specific adsorbent was created by entrapping poly[(3-methyl-1-vinylimidazolium chloride)-co-(1-vinylpyrrolidone)] in the pores of the organosilica by swelling and drying to re-collapse the pores. The polymer modified SOMS was hypothesized to effectively adsorb PFAS through the combination of both hydrophobic <i>and </i>ionic interactions. Column-scale experiments were conducted to determine the absorption capacity for multiple PFASs (PFDA, PFNA, PFOA, PFHpA, PFHxA, PFPeA, PFBA, PFOS, PFHxS, PFBS, PFOSA, PFOSaAm). Capacity at breakthrough for PFOA (Co= 200 mg/L) was found to be 11 mg/g, compared to 0.5 mg/g for GAC. Column experiments were also run to examine selectivity by using natural water and water with 5 ppm BTEX as a co-solute. Results indicate that the adsorption capacity for PFAS solutes are not significantly affected by NOM or hydrocarbon solutes, presumably due to the adsorbent’s ability to swell which provides additional adsorption sites as the loading increases.<br/>

Column studies of PFAS adsorption by a cationic polymer modified organosilica

2019 Fall National Meeting

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