CONTEXT

Zeolites are hydrated metal aluminum silicates basically comprising a three-dimensional framework of SiO₄ and AlO₄ tetrahedra. Zeolites are characterized by their high specific surface areas, high micropore volume. One of the drawbacks of zeolites is the occurrence of restricted diffusion due to their microporous network. In order to circumvent the inherent diffusion limitations of microporous zeolite-type materials, it is known to introduce a secondary porosity consisting of larger pores, i.e. macropores and/or mesopores through the removal of a fraction of framework atoms. However, so far, proposed methods to introduce said secondary porosity all show disadvantages.

TECHNICAL DESCRIPTION

In the present work, the inventors have developed an ammonium fluoride-based  preparation method of synthetic crystalline zeolite material which either increases the micropore volume or introduces a secondary porosity comprising mesopores and eventually macropores, thus expanding the channels/cavities dimensions in any framework type of crystalline zeolite material, without any substantial change in its chemical composition (e.g. Si/Al molar ratio), its surface chemical composition, its acidic properties, and its hydrophilic/hydrophobic properties.

DEVELOPMENT STAGE

Many synthetic crystalline zeolite materials has been prepared on a lab scale using patented method.
Said materials have also been characterized (including their catalytic activities).

BENEFITS

The method of the present invention is neither Si nor Al selective, and thus etches the zeolite material without altering its framework composition.
Said method:

• Is rapid
• Is simple
• Is safe
• Does not require any specific equipment.
• Leads to synthetic crystalline zeolite materials having improved diffusion and/or controlled acidity, and therefore, better overall catalytic performances.
• Does not consume much energy in contrast to high temperature steaming processes presently used in the industry.
• Generates less toxic waste.

INDUSTRIAL APPLICATIONS

Zeolites as microporous inorganic materials have different applications, such as catalysts (e.g. use in heterogeneous catalysis), absorbents, ion-exchangers, and membranes in many chemical and petrochemical processes (e.g. in oil refining, fine- and petro-chemistry) due to their superior properties including mechanical strength, acidity, size or shape selectivity, thermal and chemical stability, and large ion-exchange capacity.

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