Abstract: The 4A, 13X and LSX were ion exchanged by Ca2＋ in water solution, and the adsorption isotherms and breakthrough curves of these zeolites were measured at 25 ℃. The data demonstrate that the 4A, 13X and LSX ion-exchanged by Ca2＋ have higher adsorption capacity of N2 than the original ones, but the adsorption capacity of Ar for Ca2＋ exchanged zeolites is almost the same as that of the original ones. It is clear that these Ca2＋ exchanged zeolites have better adsorption selectivity for N2 than for Ar. From breakthrough curves it is known that the zeolites have a suitable pressure for adsorption separation of N2 and Ar. In the pressure range we studied, the best pressure is about 0.6 MPa. The adsorption capacities of N2 and Ar for the gas mixtures can be obtained from the breakthrough curves. Compared with the adsorption capacity of pure N2 and Ar, it can be found that nitrogen in the mixtures has a large effect on the argon adsorption capacity of the zeolites, which have higher adsorption separation selectivity for N2 and Ar.

Key words: Zeolite 4A, Zeolite 13X, Zeolite LSX, Adsorption isotherm, Breakthrough curve