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Study of small-port and large-port mordenite modifications. Part 1.—Preparation of the HM forms

Authors :
Edouard Freund
Francis Raatz
Christian Marcilly
Source :
Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases. 79:2299
Publication Year :
1983
Publisher :
Royal Society of Chemistry (RSC), 1983.

Abstract

Two procedures for the preparation of HM forms from both small-port mordenite (SPM) and large-port mordenite (LPM) have been studied. The procedures are acid attack of the NaM form and calcination of the NH4M form. The solids were characterized by chemical analysis, benzene adsorption, X-ray diffraction and precise measurements of the Al Kβ X-ray fluorescence line shifts. The conditions under which SPM can acquire LPM adsorption properties were determined: first, SPHM forms have been proved to exist, thus ruling out the hypothesis of pore blocking by cations; secondly, SPM pore unblocking occurs only when > ca. 20% of AlIV atoms are extracted from the framework. This result can be achieved either by severe acid attack of SPNaM or calcination of SPNH4M under deep-bed conditions. In addition, depending on the calcination procedure, the porosity of LPM itself can be blocked by AlVI species from framework dealumination.

Details

ISSN :
03009599
Volume :
79
Database :
OpenAIRE
Journal :
Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases
Accession number :
edsair.doi...........52920487db9122cfba02b85021566346