Aluminosilicate zeolite synthesis from alkaline

An alternative hypothesis, developed from studies of the synthesis of Linde A zeolite carried out by Kerr (5) and Ciric (6), pointed to growth occurring from solution. The gel was believed to be at least partially dissolved in solution, forming active aluminosilicate species as well as silicate and aluminate ions. These species linked to form the basic building blocks of the zeolite structure and returned to the solid phase. Aiello et al. (7) followed the synthesis from a highly alkaline clear aluminosilicate solution by electron microscopy, electron diffraction, and x-ray diffraction. These authors observed the formation of thin plates (lamellae) of amorphous aluminosilicates prior to actual crystal formation. 

Synthesis of M41S mesoporous materials was attempted using MFI type zeolite as sources of silica and aluminum, that is, dissolution of MFI zeolite in an alkaline solution and successive precipitation of dissolved aluminosilicate species with a surfactant, cethyltrimethylammonium bromide (CTAB). Pure phase of M41S was obtained when the filtrate of alkali-treated slurry was mixed with CTAB and crystallized at 293K. The M41S materials obtained in this method showed a catalytic activity originated from Bronsted acid site of the parent MFI zeolite. This method enables us to obtain a new type of mesoporous materials, which have both characteristics of zeolitic and mesoporous materials a strong Bronsted acidity and mesopores with a uniform size. 

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