CADMIUM ION-EXCHANGE IN ZEOLITE-Y BY CHEMICAL-VAPOR-DEPOSITION AND REACTION

Cadmium ions have been introduced in extra-framework positions of zeol ite Y by vapour deposition of cadmium metal in HY and subsequent redox reaction. The samples so-obtained have been investigated with carbon monoxide and xenon adsorption as well as with Xe-129 NMR spectroscopy. Unusual distributions of the Cd2+ ions with preference for the low ox ygen-coordinated S III sites in the supercages were detected. A subseq uent rehydration/dehydration cycle leaves the sample with a Cd2+ distr ibution similar to zeolites obtained by conventional aqueous ion excha nge.