Development of Clay Nanocomposite Hydrogels for Pfas Remediation

Environmental contaminants can be extremely harmful to humans and animals in high concentrations within the body. Per-and polyfluoroalkysubstances (PFAS) are a class of environmental contaminants that are considered forever chemicals because of the difficulty for it to degrade in the environment, which makes it a very dangerous substance when it accumulates in the human body and environment. Enterosorbents are a class of natural and synthetic materials that are orally administered and pass through the GI tract removing harmful contaminants. Clay is a sorbent material that has proven to bind a range of molecules and transport them without displaying toxic effects within the body. It can also be incorporated into a hydrogel, a hydrophilic crosslinked network, to increase the hydrophobic nature of the material for greater binding affinity. A series of acrylamide-based hydrogel nanocomposites were developed with montmorillonite clay to remove PFAS from the human body. The crosslinker N,N’-methylene-bis-acrylamide (NNMBA) was used, and the initiator ammonium persulfate (APS) and activator tetramethylethylenediamine (TEMED) allowed for free-radical polymerization to occur. The use of crosslinked hydrogels as enterosorbents and the ease of functionalization allow for highly selective materials with affinity towards specific compounds. Values of 0.1, 1, 5, and 10 mole percent of the crosslinker to the total monomer hydrogels and nanocomposites were developed. Swelling studies were performed on all systems with the neat (without clay) polymers having a swelling ratio of 8.07 ± 2.22 (0.1% NNMBA), 5.69 ± 0.06 (1% NNMBA), 3.06 ± 0.05 (5% NNMBA) and 2.55 ± 0.05 (10% NNMBA). As the percentage of crosslinker (NNMBA) increases, the swelling ratio decreases, and this is consistent across both the 1% and 5% weight loading of clay. Future sorption studies utilizing perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) will be performed to determine the binding capabilities of these enterosorbents.