Importance of Blocking Inaccessible Voids on Modeling Zeolite Adsorption: Revisited

We have carried out a geometry-based
analysis of the need of artificial blocking in a collection of zeolites,
for various gases of industrial and environmental relevance (carbon
dioxide, methane, nitrogen, oxygen, and argon), and we have studied
its influence on the heats of adsorption and saturation uptakes, which
are key properties for gas separation and storage, respectively. Our
results highlight the importance of blocking some of the pores of
the zeolites in order to avoid the spurious inclusion of guest molecules
in inaccessible regions during Monte Carlo simulations. We can thus
avoid the overestimation of adsorption and also identify nonadsorbent
zeolites for these gases by introducing pore blockings. We discuss
the limitations of the current approaches to perform automatic blocking,
and we check the reliability of the results obtained with our blocking
method, by comparing with self-diffusion coefficient values calculated
using molecular dynamics simulations.