Adsorbents comprising swellable organically modified silica were characterized to optimize the adsorption of a wide range of perfluoroalkyl substances from water.

A passive sampler designed to measure per-and polyfluoroalkyl substances (PFAS) was evaluated to determine chemical uptake rates under a variety of conditions. The sampler design is simple and robust, using organosilica modified with cross-linked amine polymer in an high density polyethylene housing retained with polypropylene mesh. The addition of amine groups as a weak ionexchange resin in combination with Cu 2+ was designed to promote binding of short-chain PFAS. A five-fold improvement in perfluorobutanoic acid adsorption was measured when Cu 2+ was added to the polyethylenimine polymer. The samplers showed an integrated response to all analytes tested except for shortchain PFAS. Sampling rates of PFAS analytes from simulated groundwater were on average 10 mL/day at flow rates of 0.038-1.9 cm/min. Relatively low variability in sampling rate was observed over the range of laboratory tested conditions (representing common conditions in environmental waters) including elevated ionic strength, sulfate concentration, and humic acid content.