Ligand-functionalized MOFs for efficient degradation of refractory organic pollutants in water: Unraveling the synergistic mechanism of adsorption and catalysis

In this study, a series of functionalized metal-organic frameworks (MOFs) were synthesized through ligand functionalization strategies to degrade refractory organic pollutants (ROPs) in water. The regulatory effects of functional groups on the morphology and surface properties of the catalysts were systematically investigated. The influence of different functional groups on the adsorption and catalytic performance was evaluated. Results showed amino-functionalized MOFs exhibited the optimal performance: their saturated adsorption capacity was 91.9 % higher than pristine MIL101. Under adsorption-catalysis synergy, the maximum removal capacity for sulfamethoxazole (SMX) reached 40.82 mg/g, 2.49 times that of MIL101. Combined experiments and density functional theory (DFT) calculations revealed that amino groups enhanced MOFs’ electron density via electron-donating effects (improving SMX binding energy in adsorption) and reduced interface resistance (promoting electron transfer kinetics in catalysis). Mechanism studies identified SO₄·⁻, ·OH, and ¹O₂ as the key active species. Based on liquid chromatography-mass spectrometry (LC-MS) analysis, the possible degradation pathway of SMX was proposed. This work confirms ligand functionalization boosts MOFs’ synergistic adsorption-catalysis performance, providing a theoretical basis for designing efficient water treatment materials. Mechanism diagram of SMX degradation by ligand-functionalized MIL101.