Methane on Zn(bdc)(ted)0.5 metal–organic framework: Evidence for adsorption on distinct sites

Zn(bdc)(ted)0.5 is a metal–organic framework with a 3D porous structure containing intersecting channels with two different size windows. Methane adsorption isotherms were measured on this MOF at several temperatures between 88 and 103 K. Unlike all other previous studies conducted on this sorbent, we observed two very distinct substeps in the isotherms, while only one such feature is reported in other studies. Possible scenarios for explaining the origin of these newly observed features are proposed. We studied the kinetics of adsorption of methane on this sorbent for isotherms measured at four temperatures. These measurements provided us with information of how equilibrium is approached as gas was added to the sorbent. We have also calculated the pore volume and the effective specific surface area for this material and have obtained the isosteric heat values for methane on this sorbent from the adsorption data.

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► For the first time two substeps were found in isotherms on Zn(bdc)(ted)0.5 MOF.
► A peak was observed in the qst dependence on substrate loading.
► Long equilibration times (∼15 h per data point) were measured.