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

Xia, Q. - Presenter, South China University of Technology
Li, Z. - Presenter, South China University of Technology
Xiao, J., South China University of Technology
Lv, D., South China University of Technology
Wu, Y., South China University of Technology
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.