Determination of intracrystalline diffusion coefficient of organic solvents in metal organic framework adsorbents by zero-length column method

A special setup was assembled to study solvent adsorption by metal organic frameworks (MOFs). A blank test was run to examine the noise level and the kinetic desorption curves for solvent molecules under different carrier gas (N₂) flow rates were measured with the instrument error lying within a limited range. The desorption process could be adequately characterized by the transport of adsorbates in pores within MOFs. For the MOF samples NH₂-MIL-101(Fe), HKUST-1, MIL-101(Cr), ZiF-67, and ZIF-8, the intercrystalline diffusion coefficient of ethanol, toluene, and propan-2-ol at 25, 35, and 45 °C were calculated and the activation energy was evaluated. The diffusion data obtained are in agreement with those reported earlier.