Calorimetric Heats of Adsorption and Adsorption Isotherms. 3. Mixtures of CH4 and C2H6 in Silicalite and Mixtures of CO2 and C2H6 in NaX

Individual heats of adsorption and selectivity of mixtures have been measured simultaneously in a calorimeter. After the weakly adsorbed component was preloaded the dosing of both components to the sample cell was adjusted to hold the loading of the weakly adsorbed component constant. Agreement with ideal adsorbed solution theory is quantitative for mixtures of CH4 and C2H6 at low coverage in an adsorbent with a weak electric field (silicalite). Mixtures of quadrupolar (CO2) and nonpolar (C2H6) gases in an adsorbent with a strong electric field (NaX) exhibit strong negative deviations from ideality. The experimental heats of adsorption are larger than those for an ideal solution, in agreement with the results of molecular simulation.