Silver-Functionalized Ionic Liquid@MCM-41 Adsorbents for C2H4/C2H6 Separation

Ionic liquids (ILs) have attracted considerable attention for light olefin separation owing to their negligible vapor pressure, excellent thermal stability, and tunable molecular structures. However, their intrinsically high viscosity severely restricts gas diffusion, leading to poor mass-transfer efficiency and limited separation performance in bulk form. Herein, we report the develop a high-performance adsorbent by immobilizing a silver-functionalized ionic liquid within ordered mesoporous MCM-41 to overcome the diffusion limitations of bulk ILs. The IL@MCM-41 composites were prepared via an impregnation–evaporation strategy, and their mesostructural integrity and textural evolution were confirmed by XRD and N2 sorption analyses. Their C2H4/C2H6 separation performance was subsequently evaluated. The composite with a 70 wt% IL loading achieves a high C2H4 uptake of 25.68 mg/g and a C2H4/C2H6 selectivity of 15.59 in breakthrough experiments (298 K, 100 kPa). X-ray photoelectron spectroscopy results are consistent with the presence of reversible Ag+–π interactions, which governs the selective adsorption of C2H4. Additionally, the composite exhibits excellent thermal stability (up to 570 K) and maintains stable separation performance over 10 adsorption–desorption cycles. These IL@MCM-41 composites have significant potential for designing sorbent materials for efficient olefin/paraffin separation applications.