MOLECULAR SIEVE SORBENTS FROM CLINOPTILOLITE

Abstract

Clinoptilolite has been investigated as a source of porous, largely crystalline, molecular sieve sorbents. By treating the zeolite with mineral acid of different strengths a range of high area sorbents has been produced, in which all the original cations have been replaced by hydronium ions, and in which the aluminum has been progressively removed from the frameworks. The new sorbents and the original clinoptilolite have been characterized by sorption studies, and by X-ray, electron optical, differential thermal analysis, and thermogravimetric methods. The most open molecular sieve sorbents, able to imbibe considerable amounts of larger molecules such as benzene and isopentane, were obtained using 1 N and 2 N acid, but as acid strength increased further there was a decline in both crystallinity and sorption capacity until with 30 N acid an amorphous product resulted.