The binary adsorption of nitrogen and carbon dioxide on zeolite-X was investigated. The adsorption equilibria of pure and binary systems were measured by static methods. In the binary system the equilibrium Selectivity of CO₂ over N₂ was very high: about 525 at a CO₂ mole fraction of 0.14 and a temperature of 15°C. Consequently, N₂ can be considered as inert when its mole fraction is less than 0.8. The ideal adsorbed-solution theory (IAST) predicted quite well the binary equilibrium data, while the extended Langmuir isotherm showed a great deviation. The dynamics of fixed-bed adsorption of CO₂-N₂ gas mixture (CO₂ 14.86 mole percent) was analyzed by the cell model under non-isothermal conditions, incorporated with binary adsorption equilibria, mass and heat transfer resistances and variation of gas velocity in the bed. The concentration and temperature history curves were determined and compared with the theoretical results. This cell-model with IAST predicted well the dynamic behavior of the adsorption bed.