(321g) Development of Cationic Hydrogel PAC Composites for PFAS Remediation in Aqueous Systems and the G.I. Tract

Per- and polyfluoroalkyl substances (PFAS) have been used in a wide variety of products and since resulted in accumulation in the environment and within our drinking water as a result of their persistent nature. Legacy PFAS compounds including perfluorooctanoic acid (PFOA) and perfluorooctanoic sulfonic acid (PFOS) have been connected to a myriad of harmful health impacts including decreased antibody response, dyslipidemia, and increased risks to several types of cancers. Current PFAS remediation treatments within the environment and our water sources include granular activated carbon (GAC) adsorption, separation by reverse osmosis and nanofiltration membrane systems, and formation of ionic bonds between anion exchange resin (AER) and negatively charged PFAS. Although these methods have high sorption capacity, some disadvantages including lack of selectivity and susceptibility to fouling which decreases efficiency, leading to the need for new cost-effective and efficient technologies for PFAS removal. Additionally, these techniques are limited to treating aqueous sources and not directly treating humans who have been exposed to PFAS. Enterosorbents are orally administered sorbents that bind to specific contaminants in the GI tract before excretion from the body. Novel materials based on synthetic sorbents, including hydrogels and hydrogel composites, have recently gained attention for remediation of these contaminants due to their high-water retention capacity and ease of tunability for increased PFAS affinity. Herein, cationic acrylamide-based hydrogels were synthesized using two cationic co-monomers, (3-acrylamidopropyl)ammonium chloride (DMAPAQ) and diallyldimethylammonium chloride (DADMAC), meanwhile, composites incorporated two particulates including powdered activated carbon (PAC) within the network. Materials were then characterized to confirm successful polymerization, and physicochemical analysis was completed, including Fourier-Transform infrared spectroscopy (FTIR) to discern its chemical composition, thermogravimetric analysis (TGA) to identify varying particulate loading percentage, and aqueous swelling for expansibility behavior. Sorbents were then subject to aqueous sorption studies to determine the affinity of PFOA and PFOS, and two short-chain analytes, perfluorobutanoic acid (PFBA) and perfluorobutanesulfonic acid (PFBS), to compare the impacts in sorption between long-chain and short-chain compounds, as well as measure influence of sulfonic versus carbonic functionality. FTIR confirmed expected functionalization of cationic materials, TGA analysis confirmed the varying concentrations of PAC and clay within the network, and the swelling ratio decreased with increasing crosslinking density and increased with the inclusion of DADMAC and DMAPAQ, as expected. Sorption of PFAS was detected via liquid chromatography tandem mass spectrometry (LM-MS/MS) where binding of PFAS was enhanced with increasing cationic functionality as well as with increasing particulate loading density. Finally, sorbent were analyzed in in vivo studies to determine enterosorbent efficacy with high safety and protection of species observed following PFAS exposure.