Boosting Acetylene Packing Density within an Isoreticular Metal-Organic Framework for Efficient CH/CO Separation.

Porous solid adsorbents for CH/CO separation are generally confronted with poor stability, high cost, or high regeneration energy, which largely inhibit their industrial implementation. A desired adsorbent material for practical implementation should exhibit a good balance between low cost, high stability, scale-up production feasibility, and good separation performance. An effective strategy is herein explored based on reticular chemistry through embedding methyl groups in a prototype microporous metal-organic framework (MOF) featuring low cost and high stability to effectively separate an CH/CO mixture. The anchored methyl groups on the pore surfaces could strongly boost the CH packing density and specifically enhance the CH/CO separation performance, as distinctly established by single-component gas sorption isotherms. The CAU-10-CH material exhibits an excellent CH packing density of 486 g L and high adsorption differences between CH and CO uptake (147%), outperforming the prototype benchmark material CAU-10-H (392 g L and 53%). The highly selective adsorption of CH over CO was achieved by a lower CH adsorption enthalpy (25.18 kJ mol) compared to that with unfunctionalized CAU-10-H. In addition, dynamic column breakthrough experiments further confirm CAU-10-CH's efficient separation performance for the CH/CO mixture. CAU-10-CH accomplishes the benchmark balance between cost, stability, scale-up, and separation performance for CH/CO separation, establishing its promise for industrial implementation. This approach could further facilitate the development of advanced MOF adsorbents to address challenging separation processes. Thus, this study paves the route for the practical implementations of MOF materials in the gas adsorption and separation field.