(167aw) Development of Hydrogel Composites for PFAS Removal in Aqueous Systems

Per- or polyfluoroalkyl substances (PFAS) are anthropogenic surfactants developed for a plethora of applications, and as a result of their prevalence and persistence in the environment, some PFAS have been connected to a myriad of harmful health impacts including immunosuppression, birth defects in newborns, and several types of cancers. Current treatments for PFAS remediation in the environment and water sources include granular activated carbon (GAC) adsorption, reverse osmosis and nanofiltration membrane separation, and anion exchange resin (AER) which have shown to be unselective when competing with other anionic compounds and are immensely expensive, respectively. Hence, the need for new cost-effective and efficient technologies for PFAS removal is of utmost importance. Novel materials based on natural polymers (i.e. cellulose and chitosan) and synthetic sorbents (i.e. hydrogels and hydrogel nanocomposites) have recently gained attention for remediation of these contaminants due to their high-water retention capacity and low production cost. Herein, acrylamide-based hydrogel composites were synthesized with powdered activated carbon (PAC) and characterized to determine their affinity for PFAS. Physicochemical characterization included Fourier-Transform infrared spectroscopy (FTIR) to identify chemical composition, thermogravimetric analysis (TGA) to confirm PAC loading percentage, aqueous swelling for expansibility behavior, and sorption studies for affinity of perfluorooctanoic acid (PFOA) and perfluorooctanoic sulfonic acid (PFOS), to compare impacts of sulfonic versus carbonic functionality of PFAS. FTIR confirmed expected functionalization with observation of carbonyl and amine groups with absorption peak at 1647 cm^-1 and the doublet peaks between 3100-3400 cm^-1, and TGA analysis also confirmed the loading of the PAC within the network. Congruently, the swelling ratio decreased with increasing crosslinking density, as expected. Finally, sorption of PFAS was detected via liquid chromatography tandem mass spectrometry (LM-MS/MS) with removal efficiencies of up to 98% of PFOS and 96% of PFOA with the 5% PAC loaded systems.

Research reported was supported by NIEHS/NIH grant P42ES007380. The content is solely the responsibility of the authors and does not necessarily represent the official views of NIH.