Abstract: The equilibrium data or CO-CO2, CO-N2 on active carbon-supported copper were predicted by the potential-theory model proposed by R. T. Yang et al. and tested against experimental data with satisfactory result, especially for CO-CO2 system, which show an azeotropic behavior. The prediction requires only experimental equilibrium data of single gas adsorption on the adsorbent, which are correlated by Dubinin-Astakhov equation. In contrast with the potential theory model, Flory-Huggins vacancy solution theory model and loading ratio correlation equation failed to predict the adsorption of CO-CO2 on active carbon-supported copper, because the adsorption of CO on the adsorbent was attributed to the formation of complex between CO and copper supported on active carbon.