posted on 2019-06-18, 19:13authored byOmid T. Qazvini, Ravichandar Babarao, Shane G. Telfer
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.