Defective MOF-808 functionalized with electronically tunable deep eutectic solvents as a dual-functional platform for...

The escalating environmental and health risks posed by per- and polyfluoroalkyl substance (PFAS) pesticides, particularly flufenacet, demand integrated, sustainable, and efficient strategies that bridge selective analysis from complex matrices and bulk removal from aqueous environments. Herein, we report the first dual-functional platform that unites defect-engineered MOF-808 with an electronically tunable deep eutectic solvent (DES) to achieve simultaneous flufenacet microextraction and adsorptive removal. Defective MOF-808 was synthesized via a straightforward hydrothermal method. A series of DESs with systematically varied electronic structures were constructed from para-substituted trifluoromethoxybenzene derivatives (-NH₂, -OH, -F, -CN, -SO₂NH₂) and levulinic acid, enabling tunable non-covalent network interactions. The optimized MOF-808/DES-SO₂NH₂ composite achieved a maximum adsorption capacity of 466.22 mg g^-1, threefold higher than ideal MOF-808 in real water matrices, with removal efficiencies exceeding 95%. The integrated thin-film platform enables simple, automatable, and environmentally benign sample pretreatment, avoiding toxic solvents and cumbersome procedures, and achieved a detection limit of 0.1 ng L^-1 with a linear range of 0.05-500 ng mL^-1 in complex wine and grape juice matrices. The DES functions as a hydrogen-bonding-network-engineered "structural switch" that shields competitive adsorption from natural organic matter while maintaining rapid mass transfer through the preserved hierarchical porosity. Mechanistic insights from ab initio molecular dynamics simulations and spectroscopic characterization reveal synergistic hydrogen-bonding and halogen-halogen interactions governing selective flufenacet recognition and capture. This work establishes a paradigm for rationally designing DES-MOF composites toward PFAS pesticide monitoring and remediation. Furthermore, this study presents a modular design strategy for DES-functionalized green materials, extending beyond flufenacet to address broader PFAS pesticide contamination challenges.