Determination of the framework and non-framework [SiO2] and [AlO2] species of steamed and leached faujasite type zeolites:: calibration of IR, NMR, and XRD data by chemical methods

Zeolite Y was thermochemically dealuminated (DAY) by steaming for 7 h at 873 K. The total concentrations of the [SiO2] and [AlO2] building units of zeolites Y, DAY and its acid-(DAY(acid)), alkaline-(DAY(alkaline)), and successively alkaline- and acid-(DAY(alkaline-acid)) leached forms, separately for their dissolved and solid components, were determined wet chemically. Non-framework species of the solids were quantified using the molybdate and ferron chemical methods and they were identified as aluminosilicate (DAY, DAY(alkaline)) and silica gels (DAY(acid), DAY(alkaline+acid)). Chemical mass balances were used to calibrate IR, NMR and XRD data to the Si/Al ratios of the zeolite framework without superimposition of the framework with non-framework species. (C) 2002 Elsevier Science Inc. All rights reserved.