Adsorption-Induced Deformation of Zeolites 4A and 13X: Experimental and Molecular Simulation Study

Gas adsorption in zeolites leads to adsorption-induced
deformation,
which can significantly affect the adsorption and diffusive properties
of the system. In this study, we conducted both experimental investigations
and molecular simulations to understand the deformation of zeolites
13X and 4A during carbon dioxide adsorption at 273 K. To measure the
sample’s adsorption isotherm and strain simultaneously, we
used a commercial sorption instrument with a custom-made sample holder
equipped with a dilatometer. Our experimental data showed that while
the zeolites 13X and 4A exhibited similar adsorption isotherms, their
strain isotherms differed significantly. To gain more insight into
the adsorption process and adsorption-induced deformation of these
zeolites, we employed coupled Monte Carlo and molecular dynamics
simulations with atomistically detailed models of the frameworks.
Our modeling results were consistent with the experimental data and
helped us identify the reasons behind the different deformation behaviors
of the considered structures. Our study also revealed the sensitivity
of the strain isotherm of zeolites to pore size and other structural
and energetic features, suggesting that measuring adsorption-induced
deformation could serve as a complementary method for material characterization
and provide guidelines for related technical applications.