Metal-organic frameworks as platforms for the removal of per- and polyfluoroalkyl substances from contaminated waters

Poly- and perfluoroalkyl substances (PFAS) have received considerable attention due to their toxicity, ubiquitous presence, and recalcitrance in the environment. The manufacturing and disposal of PFAS-containing products has resulted in PFAS contamination of groundwater and drinking water supplies. Substantial interest and efforts in developing PFAS treatment technologies has been triggered since PFAS are associated with numerous adverse health effects. Physical separation using activated carbon and ion exchange is the most widely adopted technique for PFAS removal from contaminated water. However, both adsorbents generally exhibit low PFAS adsorption capacities and/or slow adsorption kinetics. The development of efficient adsorbents is of urgent need. Metal-organic frameworks (MOFs) are an emerging class of hybrid crystalline nanoporous materials, which are composed of inorganic and organic building blocks to form multidimensional networks. Key features—tunable structures and high internal surface areas—render MOFs as ideal platforms for PFAS removal from aqueous environments. This review critically examines the application of MOFs for PFAS removal and highlights the structural features of MOFs in context of their PFAS removal performances. Factors affecting the adsorption efficiency, regeneration, and application for PFAS detection are extensively discussed while also providing important insights on design strategies for next-generation MOF materials with improved PFAS removal performances.