Facet-dependent adsorption of PFOS and 6:2 Cl-PFESA onto hematite surfaces.

Facet-specific adsorption of PFOS and 6:2 Cl-PFESA onto hematite surfaces is supported by DFT calculations showing the (012) facet has the highest affinity.

• Why it matters: Understanding how PFAS interact with minerals like hematite is crucial for predicting their transport and fate in groundwater, yet molecular-scale mechanisms remain unclear.
• What they did: The study used batch experiments, spectroscopy, surface complexation modeling, and DFT calculations to investigate PFOS and 6:2 Cl-PFESA adsorption on hematite, revealing the influence of surface facets, molecular structure, and chemistry.
• The result: Findings suggest that adsorption involves outer-sphere complexation and hydrophobic interactions, with the (012) facet exhibiting the strongest binding, aiding predictions of PFAS mobility in iron oxide-rich environments.