(668g) Ultrahigh CO2/CH4 and CO2/N2 Adsorption Selectivities on a Cost-Effectively L-Aspartic Acid Based Metal-Organic Framework

sing porous materials to selectively adsorb CO₂ from flue gas or natural gas is a promising method for purifying methane and mitigating CO₂ emission. Here, we synthesized an L-aspartic acid based microporous metal-organic framework (MIP-202) and studied its adsorptive separation performance for CO₂/CH₄ and CO₂/N₂ mixtures by measuring isotherms and breakthrough curves. Results show that MIP-202 had ultrahigh CO₂/CH₄ (72.9 and 241.5 for CO₂/CH₄ = 50/50 and 10/90, respectively) and CO₂/N₂ (1950000 and 2129.1 for CO₂/N₂ = 50/50 and 15/85, respectively) IAST selectivities at 298 K and 100 kPa. The high selectivity was verified by the calculations of Henery’s law selectivity and breakthrough experiments. Metropolis Monte Carlo simulation calculations show that CO₂ with greater polarizability and quadruple moment tends to concentrate in the large cages (containing high-density amino groups), while the less polar CH₄ or N₂ majorly being adsorbed in the small cages, resulting in the ultrahigh CO₂/CH₄ and CO₂/N₂ separation selectivities. MIP-202 exhibits low adsorption enthalpy (17.2-30.7 kJ/mol), superior persistent reusability after five cyclic adsorption experiments and easy desorption performance at 298 K. The not bad water and moisture stability of MIP-202 was demonstrated by immersing the material in water for 1 and 3 days and exposing the material to 80% RH for 20 days. MIP-202 has low ligand cost , and it can be shaped into MIP-202 extrudates by an extrusion molding method using HPC as the binder. This work shows that MIP-202 is an industrially promising material for the separation of CO₂/CH₄ and CO₂/N₂ mixtures.