The micropore model has an exponent

The micropore model has an exponential dependence with temperature in the form D 5D exp(2E /RT) where D is the limiting diffusivity at high temperatures and E is the activation energy. From the experiments for propane diffusion reported in Table 5 the activation energy of 33.7kJ/mol has been calculated which is higher than the value of 29 kJ/mol reported for CMS 5A [9]. This indicates that even with a wide micropore distribution, the smaller micropores impose a higher resistance controlling the diffusion step.