Molded fiber-supported POM@UiO-66-NH2 composite: facile synthesis and superior performance in ultra-deep oxidative desulfurization

In recent years, the escalating global demand for clean energy has underscored the urgency of developing high-efficiency fuel desulfurization technologies. This study reports the facile synthesis of a molded fiber-supported composite catalyst, POM@UiO-66-NH 2 @CF (PU N C), via impregnation, integrating polyoxometalates (POMs) with amino-functionalized metal–organic frameworks (MOFs) on cellulose fibers (CF). The catalyst delivers exceptional performance in ultra-deep oxidative desulfurization (ODS), enabled by systematic optimization of reaction parameters using response surface methodology (RSM) with a Box-Behnken design (BBD). Through RSM optimization and adjustment, the actual desulfurization conditions were determined as 66 °C, O/S = 7, 7 mL DMF, and 2 catalyst pieces and PU N C achieved a validated 99.26 % desulfurization efficiency for dibenzothiophene (DBT) in model fuels, demonstrating close agreement with theoretical predictions. Kinetic analysis revealed the ODS reaction conformed to a pseudo-first-order kinetic model with a low activation energy of 2.45 kJ/mol, while EPR spectroscopy confirmed ·O 2 − radicals as the dominant reactive species, highlighting a POM-mediated radical oxidation pathway. PU N C exhibited robust reusability, maintaining >95 % efficiency over 5 consecutive cycles. The catalyst’s performance is attributed to the synergistic architecture of MOF-fiber supports, where 3-chloropropyltrimethoxysilane (CPTMS) enables covalent bonding of UiO-66-NH 2 to CF, creating amine-rich sites for electrostatic POM immobilization and enhanced stability. This work showcases the synergy between structural design and RSM-driven optimization, offering innovative insights for developing high-efficiency, environmentally benign molded catalysts for ultra-deep ODS and related oxidative processes.