Adsorption of N-2 and CO has been studied on a natural Turkish clinoptilolite at near ambient conditions. Pure isotherms up to 101.3 kPa pressure, and binary isotherms at 101.3 kPa total pressure were determined chromatographically at 303 K. Pure isotherms were modelled using the Langmuir model and the Wilson and Flory - Huggins forms of the Vacancy Solution Theory. Binary isotherms were predicted using both forms of the Vacancy Solution Theory, the Extended Langmuir model, and the Ideal Adsorbed Solution Theory. These predictions were compared to experimentally determined binary isotherms. Clinoptilolite is shown to be a particularily promising sorbent for the separation of CO and N-2. The Wilson form of the Vacancy Solution Theory was the only model flexible enough to provide a reasonable prediction of the binary isotherms.