Characterizing the efficiency of mineral amendments in immobilizing PFAS

Per- and Polyfluoroalkyl substances (PFAS) are a family of chemicals added to many hydrophobic anthropogenic materials. PFAS however is a toxic substance that does not break down naturally and is expensive to destroy. These compounds can be extremely soluble, often contaminating drinking sources in areas where materials containing PFAS are widely used. Due to PFAS containing firefighting foams used to extinguish petroleum-based fires, airports are examples of areas that are commonly polluted. This study focuses on the efficiency of iron-based and activated carbon-based (peat) amendments in immobilizing perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) from simulated groundwater, an organic and inorganic remediation option that is considered safe in various environmental systems. We used fixed column systems and batch reactors to assess the relationship between ionic strength and sorption isotherm. This study also used an electron probe micro-analyzer (EPMA) and scanning electron microscope (SEM) to investigate the integrity of the amendments over time. Amendments were analyzed for chemical morphology, surface roughness, elemental associations, particle size and aggregation as the amendments aged over fixed timeframes. Characterizing the immobility of PFOS and PFOA using iron-based and activated carbon-based amendments is integral to understanding potential long-term remediation of PFAS contaminated sites.