Equilibriums of Ethene Adsorption on 4A ZeolitesFrom the isotherms of ethene, measured on the zeolites NaA, K0,085Na0,915A and Me0,22+Na0,8(Me = Mg, Ca, Zn, Ba) in the temperature range of 298 K to 353 K, the isosteric heats of adsorption and the partial molar entropies were calculated. All three quantities show a specific dependence on the loading. The exchanged univalent and divalent cations as adsorption centres have an essential influence on the shape of isotherms. The sequence of cations ordered according to highest adsorption heats depends also on the loading, caused by the different influence of the nonloaded and loaded divalent cations on the mobility and ionizity and therefore on the adsorption strength of the blocking Na+cations.