Characterization of selenium-loaded molecular sieves A, X, Y, AlPO-5, and mordenite

Abstract

This value is much larger than the observed total surface area.If this value is divided by the total surface area, the number of boehmite layers can be calculated to be 3.8, from which the thickness of the crystallite is calculated to be 44 A. This value is in good agreement with the crystallite size determined from the Scherrer equation (50 A).Therefore, we concluded that the micropores come from interstices between crystallites.As the thickness of the platelike crystals, which form the honeycomb-like texture, was 500-2000 A, defects in stacking the boehmite layers with the openings in micropore range (520 A) are present in the platelike crystals.Moreover, careful examination of the molecular geometry (Figure 7) revealed that gaps between the boehmite layers in the product are too narrow to be accessed by nitrogen molecules, although they may be large enough for water molecules to access the internal surface because hydrogen bondings can be formed.Details of the pore textures of the product and of the aluminas derived from the product will be discussed separately.Registry No.