A Cadmium Metal-Organic Framework with Negative Electrostatic Potentials for Efficient Separation of C2H2/CO2 and C2H2/C2H4.

Given the high similarity in physical and chemical properties, especially in terms of molecular size and boiling point, of acetylene (C2H2), carbon dioxide (CO2), and ethylene (C2H4) molecules, traditional separation techniques encounter great challenges. Fortunately, metal organic framework (MOF) materials have demonstrated significant potential for efficient separation of these gases at the molecular level due to their finely tunable pore structure and surface functional properties. In this paper, we have successfully synthesized a cadmium-based MOF (FJI-W-708), which exhibits negative electrostatic potential pores and exceptional thermal stability. It is worth noting that FJI-W-708 exhibits high C2H2 capacity (61 cm3/g), as well as appropriate selectivity towards C2H2/CO2 (3.39) and C2H2/C2H4 (3.47). The dynamic breakthrough experiments of C2H2/CO2 (50/50) mixture and C2H2/C2H4 (1/99) mixture clearly demonstrated the actual separation performance. The breakthrough time for C2H2/CO2 (50/50) was observed to be 23 min/g, while for a C2H2/C2H4 (1/99) mixture it could reach up 46 min/g, demonstrating excellent recyclability and achieving a benchmark productivity of C2H4 at 4.12 mmol/g.