Prediction of Adsorption and Diffusion Behaviors of CO₂ and CH₄ in All-Silica Zeolites Using Molecular Simulation

Computational chemistry is a promising technique for the prediction of material properties. Adsorption and diffusion behaviors in zeolite micropores are important for zeolite membranes. In this study, we investigated novel non-bonding interaction parameters of all-silica zeolites for the prediction of the adsorption and diffusion behaviors by focusing on the Si atom of zeolite frameworks. Our parameters (σ = 0.421 nm, ε = 0.954 kJ mol^-1, and q = +1.10 e) were close to theoretically derived values, and the adsorption isotherms of CO₂ and CH₄ on several zeolites could be predicted with high accuracy. Furthermore, the parameters gave the suitable self-diffusivities of CO₂ and CH₄ within MFI-type zeolite micropores through molecular dynamics simulation. Those suggest that our derived parameters are useful for selecting zeolite structure as the membrane material.