Acid-Free Synthesis of MIL-101/GO Composites with Ultrahigh Selectivity for Adsorptive Separation of C3F8 from N2

As a perfluorinated compound with a high global warming potential, octafluoropropane (C₃F₈) needs to be efficiently separated from industrial waste gas, but separating it from nitrogen at low concentrations is highly challenging. To address the common drawback of using corrosive acids in conventional MIL-101(Cr) synthesis, this study developed a green, acid-free solvothermal method for preparing graphene oxide (GO)-modified MIL-101(Cr) composites (MIL-101/GO). By systematically varying the GO doping, the optimal composite (MIL-101/GO-0.1) exhibited breakthrough adsorption performance: its equilibrium adsorption capacity for C₃F₈ reached 210 mg/g in fixed-bed breakthrough experiments. The predicted C₃F₈ adsorption selectivity relative to N₂ reached 17,069, ranking among the highest values reported for adsorbents, indicating a significant performance enhancement over the pristine MIL-101(Cr). Mechanistic analysis reveals that graphene oxide not only increases specific surface area and micropore volume but also enhances dispersion forces, substantially boosting affinity for C₃F₈. Additionally, the composite exhibits outstanding cycling stability and thermal stability. This study provides a novel eco-friendly synthetic strategy for high-performance metal-organic frameworks and offers a highly promising candidate material for industrial-scale fluorocarbon recovery.