Single and Multicomponent Sorption of CO2, CH4 and N-2 in a Microporous Metal-Organic Framework

Single and multicomponent fixed-bed adsorption of CO2, N-2, and CH4 on crystals of MOF-508b has been studied in this work. Adsorption equilibrium was measured at temperatures ranging from 303 to 343 K and partial pressures up to 4.5 bar. MOF-508b is very selective for CO2 and the loadings of CH4 and N-2 are practically temperature independent. The Langmuir isotherm model provides a good representation of the equilibrium data. A dynamic model based on the LDF approximation for the mass transfer has been used to describe with good accuracy the adsorption kinetics of single, binary and ternary breakthrough curves. It was found that the intra-crystalline diffusivity for CO2 is one order of magnitude faster than for CH4 and N-2.