Hydrolytically Stable Ionic Fluorogels for High‐Performance Remediation of Per‐ and Polyfluoroalkyl Substances (PFAS) from Natural Water

Abstract

PFAS are known bioaccumulative and persistent chemicals which pollute natural waters globally. There exists a lack of granular sorbents to efficiently remove both legacy and emerging PFAS at environmentally relevant concentrations. Herein, we report a class of polymer networks with a synergistic combination of ionic and fluorous components that serve as granular materials for the removal of anionic PFAS from water. A library of Ionic Fluorogels (IFs) with systematic variation in charge density and polymer network architecture was synthesized from hydrolytically stable fluorous building blocks. The IFs were demonstrated as effective sorbents for the removal of 21 legacy and emerging PFAS from a natural water and were regenerable over multiple cycles of reuse. Comparison of one IF to a commercial ion exchange resin in mini-rapid smallscale column tests demonstrated superior performance for the removal of short-chain PFAS from natural water under operationally relevant conditions.

Imparting Selective Fluorophilic Interactions in Redox Copolymers for the Electrochemically Mediated Capture of Short-Chain Perfluoroalkyl Substances

“…This affinity for fluorocarbons is characteristic of fluorinated compounds and can leverage distinct binding mechanisms for molecules like PFAS. The concept of employing fluorinated compounds for PFAS capture has been previously reported. − For example, highly fluorinated porous cyclodextrin polymers were found to remove PFOA at environmentally relevant concentrations . Moreover, PFOA has been captured at high capacities by fluorine-rich calix[4]-arene-based porous polymers due to favorable CF···FC interactions .…”

“…Moreover, PFOA has been captured at high capacities by fluorine-rich calix[4]-arene-based porous polymers due to favorable CF···FC interactions . Recent studies have also included short-chain PFAS like perfluorobutanoic acid (PFBA) and hexafluoropropylene oxide-dimer acid (GenX), using ionic fluorogels and magnetic fluorinated polymers, showing larger removal efficiencies compared to nonfluorinated versions of the sorbents. − However, the removal efficiency decreased significantly with a decreasing chain length of the PFAS despite showing higher sorption capacities than nonfluorinated sorbents. Furthermore, there are a range of unanswered questions regarding the molecular mechanisms in which fluorinated sorbents bind short-chain PFAS and the extent to which fluorophilic interactions impact PFAS binding.…”

Linkage Transformations in a Three-Dimensional Covalent Organic Framework for High-Capacity Adsorption of Perfluoroalkyl Substances

“…Researchers have shown that adsorbents with cationic groups − or fluorocarbon chains ,, interact strongly with the respective components of PFAS adsorbates (Figure a). This strategy has borne fruit in the design of PFAS-selective COFs.…”

The Specific Removal of Perfluorooctanoic Acid Based on Pillar[5]arene-Polymer-Packed Nanochannel Membrane

“…Exposure of PFOA to soil concentrations above 800 mg L –1 caused cellular damage in the roots, stems, and leaves of wheat seedlings and inhibited wheat growth. , This is due to the ecotoxicity of PFOA resulting in reduced growth and biomass, disruption of chlorophyll accumulation, and soluble protein synthesis in wheat roots and leaves. In particular, PFOAs in food crops pose a possible risk to human health since they ultimately end up transferring poisons to humans, either directly or indirectly. − …”