Removal of Per- and Polyfluoroalkyl Substances in Water by Metal−Organic Framework Adsorption: A Review
Per- and polyfluoroalkyl substances (PFASs) are persistent contaminants that are widely detected in aquatic environments and are difficult to remove because of their stable carbon–fluorine bonds and amphiphilic structures. Metal–organic frameworks (MOFs), with high surface areas, tailorable porous frameworks, diverse metal nodes, and adjustable surface functionalities, provide promising platforms for PFAS adsorption. This review summarizes recent advances in the adsorptive removal of PFASs from water using MIL-, UiO-, ZIF-, and PCN-type MOFs and their derivatives. The effects of hydrophobic interface construction, amine functionalization, fluorination, defect engineering, thermal conversion, and pore regulation on adsorption performance were discussed. PFAS adsorption by MOFs is governed by multiple interactions, including electrostatic attraction, Lewis acid–base interactions, hydrophobic interactions, van der Waals forces, and hydrogen bonding. The impact of solution pH, coexisting ions, natural organic matter, PFAS molecular structures, and MOF structures was also reviewed. In addition, regeneration strategies and PFAS adsorption performance after regeneration were summarized. Despite the advances, challenges persist regarding MOF stability, regeneration, cost-effectiveness, and adsorption performance in real water matrices. Future research should therefore focus on sustainable material design and scalable development of MOF-based treatment systems for effective PFAS remediation.