Fungal chitin nanofibril-MOF hybrids for PFAS remediation in water: mechanism and performance-sustainability trade-off

Per- and polyfluoroalkyl substances (PFASs) are a challenging classes of emerging water contaminants due to their notable toxicity, exceptional persistence, and bioaccumulation abilities. While adsorption remains the prevailing remediation strategy, conventional sorbents, such as ion-exchange resins and activated carbon are constrained by limited capacity and sluggish kinetics. Conversely, metal–organic frameworks (MOFs) offer a tunable porosity and surface functionality, yet their high environmental footprints often impede sustainable device integration. Herein, we design hybrid cryogels through the strategic integration of low carbon footprint fungal-derived chitin and highly sorbing MOFs, a combination not reported in the literature. Among the hybrids, the 10 wt% Zr-based MOF-808 loaded material exhibited exceptional PFAS adsorption for both short- and long-chain carboxylic and sulfonic acids. A maximum removal capacity of 690 mg·g⁻¹ is achieved for perfluorodecanoic acid. The 10 wt% cryogel achieved a 426 % enhancement in performance–sustainability metric compared to the parent MOF-808, underscoring its true potential as sustainable sorbent. Mechanistic insights reveal a synergistic interface between the chitin- and MOF-matrices, fostering site-specific interactions and high PFAS binding energies. This study provides a compelling framework for the rational design of highly efficient yet environmentally sustainable sorbents, representing a significant breakthrough in environmentally friendly PFAS remediation technologies.