Equilibrium isotherms and adsorption heats analysis for ternary mixture of methane, ethane, and propane on 4A zeolite

Equilibrium isotherms were obtained experimentally and theoretically for adsorption of methane, ethane, and propane mixtures on 4A zeolite at 301 K. The experimental data were measured using constant volume method and analyzed by extended Langmuir, modified extended Langmuir, and extended Freundlich isotherm models. The best correlation was achieved with the extended Freundlich isotherm equation and the negative values for heats of adsorption indicate exothermic adsorption nature for these gases on 4A zeolite. The selectivity of 4A zeolite to adsorb gases was also studied with the observation that ethane was more selectively adsorbed than methane on 4A zeolite, while propane was less selectively adsorbed on this zeolite at the studied temperature. Also, it was found that an increase in initial partial pressure of ethane decreases the adsorbed amount of methane, while the increase in partial pressure of methane had no effect on adsorbed amount of ethane.