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(C 3 H 10 N) 2 [Zn 3 (HPO 3 ) 4 ] (ZnHPO-CJ4), have been hydrothermally prepared with
desired extra-large 24-ring channels analogous to (C 4 H 12 ) 2 [Zn 3 (HPO 3 ) 4 ] (ZnHPO-
CJ1). Such work would be highly useful for the designed synthesis of extra-large
micropore-structured materials. Yu and Xu [59] proposed rational synthesis including
the use of a template to direct the structure, the use of heteroatoms as a framework sub-
stituent, and the use of computational data mining. This has helped them to develop
innovative methods toward the synthesis of target structures with specific channel
structures, such as extra-large pores and chiral channels. Recently, Wang et al. [60]
have reviewed the needs and trends in the rational synthesis of zeolitic materials. The
geometrical characteristics of the zeolite frameworks affecting their catalytic perfor-
mances have been demonstrated. In spite of such a tremendous development in the
rational approaches toward the design and synthesis of zeolite frameworks, targeting
novel structures and functions remains a formidable task. The challenge in rational
synthesis lies in the unknown mechanism for their formation: The relationship between
the synthetic parameters and structural characteristic of the products is not clear. Yu
and Xu [59] have built up a ZEOBANK, a database of zeolite structures and a database
for their synthesis. This ZEOBANK allows us to use data mining to find new methods
for guiding the synthesis of zeolitic materials.
The general route whereby zeolites can be synthesized in a laboratory or in a plant
scale is shown in Table 6.11 [61] . The SDAs listed are only examples of a wide range
of materials that have been used. Zeolites have only been synthesized by the hydro-
thermal method. It involves silica, alumina, and/or phosphorus species, metal cations,
organic molecules, and water, which are converted via an alkaline supersaturated
Table 6.11 Molecular Sieve Zeolite Preparation Process [61]
Molecular Sieve Process
Zeolite Preparation Process
Reactants
Products
Hydrogel
Reactive oxides
High-purity powders
Soluble silicates
Gel perform
Soluble aluminates
Zeolite in gel matrix
Caustic
Clay
Raw kaolin
Low- to high-purity powder
Conversion
Metakaolin
Binderless, high purity
Calcined kaolin
Preform zeolite in clay
Soluble silicate
Derived matrix
Caustic sodium
Chloride
Others
Natural SiO 2
Low- to high-purity powder
Acid-treated clay
Zeolite on ceramic support
Amorphous
mineral
Binderless preforms
Volcanic glass
Caustic
Al 2 O 3 ,3H 2 O
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