EQUILIBRIA OF ETHENE ADSORPTION ON 4A ZEO LITES

From the isotherms of ethene, measured on the zeolites NaA, K(0,085)Na (0,915)A and Me(0,2)(2+)Na(0,8) (Me = Mg, Ca, Zn, Ba) in the temperatu re range of 298 K to 353 K, the isosteric heats of adsorption and the partial molar entropies were calculated. All three quantities show a s pecific dependence on the loading. The exchanged univalent and divalen t cations as adsorption centres have an essential influence on the sha pe 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.