Modelling diffusion in zeolites with cellular automata

Exploiting the analogy between the partitioned spatial structure of zeolites and the space-discrete nature of Cellular Automata (CA), we developed a probabilistic Cellular Automaton (CA) able to capture both static and transport properties of diffusing species in zeolites at a coarse-grained level. Our model uses cells to represent pores. It focuses on the sensitivity of each cell upon its instantaneous occupancy to mimic the particle-framework and particle-particle interactions of adsorbates into real zeolite pores. It makes use of local partition functions and kinetic barriers to build up a simple and fast evolution rule allowing our model to reproduce data such as adsorption isotherms, global and local distributions of occupancies inside of the zeolite pores, diffusivities, correlations in space and time, etc. from experimental and/or atomistic simulation. The local and parallel nature of our CA, together with its drastically reduced number of degrees of freedom makes it a powerful tool to enlarge the space-time scales of numerical simulations of diffusion in zeolites.