Effect of Decationation Procedure on the Textural Properties of High-Silica ZSM-5 Zeolite

The texture of the starting high-silica zeolite ZSM-5 and its decationated samples is studied by the low-temperature adsorption method. Mesopores with a diameter of 42 Å are found. Decationation of the zeolite is accompanied by an increase in the specific surface area and pore volume. It is suggested that the textural changes found are due to the removal of admixtures from some pores. A model for the formation of the secondary pore system is proposed. The secondary porosity is suggested to be due to the coordination of the zeolite crystals through the primary particles of aluminum hydroxide located on the surface of the zeolite crystals. The influence of the decationation conditions on the textural characteristics of ZSM-5 is shown.