Passive sampler designed for per- and polyfluoroalkyl substances using polymer-modified organosilica adsorbent

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 ion-exchange resin in combination with Cu2+ was designed to promote binding of short-chain PFAS. A five-fold improvement in perfluorobutanoic acid adsorption was measured when Cu2+ was added to the polyethylenimine polymer. The samplers showed an integrated response to all analytes tested except for short-chain 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.