Formatted Title
The Versatility of Surface-Modified Clay Adsorbents for PFAS Treatment
Background/Objectives
Surface-modified clay (SMC) adsorptive media is highly effective at removing perfluoroalkyl and polyfluoroalkyl substances (PFAS) from a variety of water types. SMC is made by loading bentonite clay with a modification agent that has a high affinity for PFAS, with hydrophobic and electrostatic mechanisms. The modification agent is attached to the plate-like crystalline structure of the clay to form adsorptive inter-platelet layers or galleries. Exchangeable cations in the clay, like sodium and calcium, are replaced, thereby eliminating swelling when hydrated. SMC removes PFAS from water and reduces or eliminates leaching of PFAS from contaminated soil.
Approach/Activities
SMC has been investigated in the laboratory and in the field for long-chain and short-chain PFAS removal from a variety of water types, including drinking water, groundwater, wastewater, and landfill leachate. The adsorptive media is resistant to the detrimental effects of water constituents, like dissolved organic carbon and anions, and provides fast adsorption kinetics, resulting in a low empty bed contact time when used in filtration vessels. SMC can also be used to stabilize PFAS in contaminated soil, injected for subsurface treatment of PFAS, and installed as a sediment cap.
Results/Lessons Learned
Results from laboratory studies, leaching studies, and field sites showing PFAS treatment in soil, groundwater, drinking water, and landfill leachate will be presented.