In this study, adsorption separation of main components of landfill gas, methane (CH4) and carbon dioxide (CO2) was carried out. Henry's law constants, limiting heat of adsorption values, pure and binary isotherms for CO2 and CH4 were determined for CaX zeolite adsorbent. Pure isotherm data were compared to those for NaX zeolite from previous studies. The CO2 adsorption capacity of CaX was greater than that of NaX; however, NaX's separation factor was higher. The heat of adsorption for CO2 for CaX was higher than those for NaX. (c) 2013 Canadian Society for Chemical Engineering