DETECTION OF SIDE-PRODUCTS ON HEAVY-METAL LOADED ZEOLITES OF TYPE-A (PBNAA ZEOLITE) .2.

During the loading of aluminosilicate zeolites type A with heavy metal cations by ion exchange, hydroxides precipitate as permanent side-pro ducts. Even smallest amounts of these surface deposits change the prop erties of the zeolite drastically, when transformed into a semiconduct or composite. Their formation is detectable during the exchange proces s by means of in-situ pH measurements. For zinc loaded zeolite A the d etection succeeds also by means of XRD measurements. A change of the f ramework symmetry of zeolite A is observed under the influence of the framework adapted zinc oxide. A change of the framework symmetry from Fm-3c to Fm-3m is detected for lead loaded A zeolites, however, it is caused by hydrated lead cations.