Mordenite is dealuminated by hidrotherrnaltreatment. Dealuminatationproduces nonframewor k alurninium NFAL. Different types of NFAL were detected, one is a cationic fype that is located in ion-exchange positions, other is a neutral type, and another an amorphous phase not "visible" to the 27Al RMN technique. The Lewis acid sites ore associated with the NFAL species locat ed in the zeolite pares. lt is not possible to find a relationshipbetween the acid-strength of Bri:insted acid siles and the structural aluminium content. However, the number of pyridine titroted acid sites increoses .alter deolum ination process. Adsorption sludies also indic□le presence of o mesoporous network in the materiols that could decrease diffusional restrictions.
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