Filtration and electrical membrane-based treatment methods for PFAS-contaminated water and preparation methods for the membranes employed

Per- and polyfluoroalkyl substances (PFAS) constitute a group of emerging contaminants in which the hydrogen (H) atoms on the carbon (C) or sulfur (S) chains are replaced by fluorine (F) atoms. These substances can be categorized into long- or short-chain PFAS (Jin et al. 2021a , b ). Long-chain PFAS have seven or more C or S atoms, such as perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and perfluorohexanesulfonic acid (PFHxS). Short-chain PFAS have six or fewer C or S atoms, such as perfluorobutanoic acid (PFBA), perfluorobutanesulfonic acid (PFBS), and GenX (hexafluoropropylene oxide–dimer acid, HFPO–DA). Long-chain PFAS were used while PFAS were first being developed but are currently more regulated than short-chain PFAS. Long-chain PFAS are stable and difficult to metabolize and are therefore more likely to accumulate in the human body than short-chain PFAS. Short-chain PFAS (e.g., PFBA and PFBS) are usually substituted for long-chain PFAS. Animals can excrete PFBA and PFBS faster than long-chain PFAS (Solan and Lavado 2022 ). However, the risk of short-chain PFAS to human health still needs to be fully evaluated (Fig. 1 ).