LTA zeolites can be synthesized with tailored adsorption properties by controlling the Al content in the framework. In this work, we have demonstrated that it is possible to adjust the polarity of the zeolitic adsorbent to optimize its thermodynamic adsorption properties for the energetically relevant CO(2)/CH(4) separation process. The thermodynamic study has been made from the corresponding adsorption isotherms of the pure gases carried out at different pressures and temperatures, as well as breakthrough separation experiments of CO(2)/CH(4) mixtures and the results were compared to those reported on MOFs. The separation values obtained allow us to conclude that LTA zeolites offer unique possibilities for CH(4) upgrading from natural gas.