Multipurpose Metal-Organic Framework for the Adsorption of Acetylene: Ethylene Purification and Carbon Dioxide Removal

The separation of acetylene, ethylene, and carbon dioxide is a great challenge in view of their similar sizes and physical properties. Recently, adsorptive separations using porous metal-organic frameworks have risen to prominence. Here, we report a novel microporous metal-organic framework, termed MUF-17, that selectively adsorbs acetylene in the presence of ethylene or carbon dioxide. MUF-17 possesses one-dimensional zig-zag pores that are lined with amino and carboxylate groups, and coordinated water molecules. This pore surface is highly polar and has appropriate dimensions to interact optimally with guest acetylene molecules. Dispersion-corrected density functional theory calculations confirm the strong interactions between the framework and acetylene and illustrate the electrostatic basis for its lower affinity for other gases. The application of MUF-17 to gas separations was demonstrated by dynamic breakthrough measurements. It is a multipurpose adsorbent, removing trace quantities of acetylene from ethylene and sequestering bulk quantities in the presence of carbon dioxide. Its excellent performance fruitfully couples high selectivity with uptake capacity. Advantageously, MUF-17 is straightforward, robust, and inexpensive to prepare. Its recyclability and high stability render it a high-performance material for sustainable and energy efficient separation processes.