Micro-cubic glass from pseudomorphism after thermal treatment of ammonium-exchanged zeolite A

Isothermal treatments of the ammonium-exchanged Na-zeolite A were carried out at 400 °C for different durations up to 1000 min in the air. The products were characterized by XRD, SEM, AFM, FT-IR, DTA and nitrogen adsorption measurement. The results confirmed that the amorphous pseudomorphism occurred, showing the tweed-like patterns on the surface of cubic solid. These characterizations supported the existence of thin surface layer of zeolite crystal as a microvessel, which was consistent with the previous hypothesis. The amorphous transformation was taking place by the mechanism, in which the zeolite framework reacted with hydrogen decomposed from ammonium ions. The obtained micro-cubic glass should be useful as an eco-functional material, such as the fixation of harmful ions.