Adsorption characteristics and the thermal stability of (Tlex, Na)-A zeolite

Abstract

Na–A zeolite was ion-exchanged with T1⁺ ions, and the molecular sieving ability of (T1^ex, Na)–A measured as a function of the degree of exchange. An abrupt change in the amount of ethane absorbed occurred at 30 % exchange, as has been previously observed in (K^ex, Na)–A. This was attributed to site selectivity of the T1⁺ ion, and so the ion-exchange scheme was determined in order to establish the cation distribution among the sites in the crystal. The stability of (T1^ex, Na)–A as a desiccant was much better than that of the Linde Sieve 3A used in industry, as checked by measuring the rate and amount of sorption of water vapour. The thermal stability was discussed on the basis of d.t.a. and X-ray pattern observations.