Perfluoroalkyl substances (PFAS) partitioning into a high-density polyethylene geomembrane

This paper investigates how five PFAS congeners, namely, perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexanoic acid (PFHxA), perfluorobutane sulfonate (PFBS) and trifluoromethanesulfonic acid (TFMS), interact with a high density polyethylene (HDPE) geomembrane, through equilibrium batch sorption tests, to assess its ability to minimise the migration of these contaminants. The sorption experiments show that the HDPE geomembrane exhibits varying degrees of uptake for different pollutants, in the following order: PFBS = TFMS < PFHxA < PFOA < PFOS. Additionally, minimal partitioning of PFAS congeners to the HDPE geomembrane was observed, with longer-chain PFAS exhibiting higher partitioning coefficients. This indicates that an intact HDPE geomembrane can potentially slow down the migration of these pollutants. PFOS exhibited a slightly stronger affinity than PFOA, likely due to its stronger hydrophobicity and/or higher electronegativity.