Process-level simulations require an analytical model to determine the equilibrium molar loadings of CO2 / N2 mixtures over various pressure and temperature domains. The dual-site Langmuir (DSL) model (Eq. (1)) is well suited for this purpose. Within the DSL approach, competitive adsorption may be calculated by a simple extension of the singlecomponent DSL models; 59 many practical systems of interest are known to be described by this behaviour.