Increase in Total Available Surface Area

1 Increase in Total Available Surface Area For conventional zeolites, having crystal sizes in the micrometer range, the proportion of external surface area is usually negligible, that is, the Brunauer-Emmett-TeUer (BET) surface area corresponds almost completely with the surface area associated to the micropores. However, in the case of hierarchical zeolites, the presence of mesoporosity implies that a great part of the surface area is related to the latter, while a reduction is usually observed in the micropore surface area compared with the standard zeolites. 

Improvement of the BET surface area, as weU as the presence of a high proportion of nonmicroporous surface area, opens the possibility of functionalizing hierarchical zeolites with different agents. Organic-functionalized hierarchical zeolites have the added advantages of their high hydrothermal stability and reusability. 

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