Mordenite zeolite is one of the most commonly used high silica aluminosilicate zeolites worldwide. It has been applied to a wide variety of industrial processes and applications requiring high acid resistance and thermal stability. This is due to its atomically well-ordered structure with regular pores of molecular dimensions, making it an excellent catalyst for heterogeneous reactions.
Mordenite is widely used in catalytic processes for the petrochemical industry for the acid-catalyzed isomerisation of alkanes and aromatics, as well as for gas separation applications. It also has a number of applications in the field of ceramics, semiconductors and nonlinear optics.
The pore system of mordenite is one of the most well-ordered in the family of aluminosilicate zeolites and exhibits a high degree of flexibility. This is due to the presence of five-membered rings with a strong hydrogen bond between silicon and aluminium atoms. The ring system also contributes to the acid resistance and thermal stability of mordenite zeolite.
Zeolites are natural or synthetic materials with a highly ordered atomic crystal structure and a special framework of ions, metals and/or non-metals. The adsorption of small molecules or ions is controlled by the size of the pore openings in these structures, which are known as molecular sieves. The size of these openings is determined by the atomic structure and the amount of water in the zeolite.
In recent years, the research on the synthesis of mordenite zeolite has gained increased attention as a cost-effective and environmentally friendly catalyst. This is mainly because of its high ratio of silica to aluminium and the ring system of the molecule, making it an effective heterogeneous catalyst with exceptional acid resistance and thermal stability.
The synthesis of mordenite zeolite is a hydrothermal process. Its preparation requires a mixture of inexpensive Si and Na sources, such as rice husk ash and waste coal fly ash, as well as an aluminium source such as metakaolin or faujasite zeolite. Moreover, the synthesis of mordenite zeolite can be performed without the need for expensive organic templates like TEA+ cation or mixed organic templates. In this article, we describe the synthesis of mordenite zeolite using a molar composition of 12Na2O:100SiO2:2Al2O3:500H2O, where the Na+ cation plays the role of a structural template to promote nucleation and crystalline growth of the zeolite.
The X-ray diffraction (XRD) patterns of the resulting zeolite sample are shown in Figure 2. Mordenite zeolite has a peak intensity at 20° with a wavelength of 2
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