The Preparation and Characterization of Aluminum-Deficient Zeolites

The preparation methods of aluminum-deficient zeolites are reviewed. These methods are divided in three categories: (a) thermal or hydrothermal dealumination; (b) chemical dealumination; and (c) combination of thermal and chemical dealumination. The preparation of aluminum-deficient Y and mordenite zeolites is discussed. The structure and physico-chemical characteristics of aluminum-deficient zeolites are reviewed. Results obtained with some of the more modern methods of investigation are presented. The structure, stability, sorption properties, infrared spectra, acid strength distribution and catalytic properties of these zeolites are discussed.