The adsorption of N2 and CO2 in the microporous aluminium methylphosphonate polymorphs alpha and beta is investigated by adsorption experiments in combination with Monte Carlo (MC) simulations. We find that close steric matching of N2 and polymorph alpha causes a packing transition not observed for the other pairs of adsorbate and adsorbent. This strong effect on adsorption behaviour of small differences in the adsorbent structure and adsorbent-adsorbate interactions suggests that microporous, hybrid inorganic organic materials of this type offer opportunities for highly selective adsorptive separations. The realism of the MC simulations is extraordinarily dependent upon the molecular size parameters used.
Adsorption Carbon Dioxide