| abstract |
Aluminum from AlO 4 - tetrahedra of as-synthesized zeolites is extracted and substituted with silicon to form zeolite compositions having higher SiO 2 /Al 2 O 3 molar ratios and exhibiting distinctive chemical and physical properties. The preparative procedure involves contact of the starting zeolite with an aqueous solution of a fluorosilicate salt using controlled proportions and temperature and pH conditions which avoid aluminum extraction without silicon substitution. |