• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07b
• /
• pp.1231-1234
• /
• 2003

A sample procedure has been described to room temperature synthesis, mesoporous aluminosilicate materials with strong surface acidity by using a cationic surfactnat cetyltrimethylammonium bromide(CTABr) as the template agent. All samples were charecterized by X-ray diffraction(XRD) and nitrogen adsorption. The crystallinity and surface area of MCM-41 type aluminosilicats decrease with decreasing of Si/Al ratio. The influence of the aluminum contents of MCM-41 on the coordination of Al and on the acidity is studied by $^{27}Al$ MAS NMR and temperature programmed desorption of ammonia(TPD). It was shown that the incorporation of Al atoms into the framework causes increasing of acid site surface. And then Al atoms in the framework were incorporated tetrahedrally in structure, which gave a rise to cationic sites in the framework.

• Economic and Environmental Geology
• /
• v.9 no.3
• /
• pp.165-168
• /
• 1976

Zeolites are aluminosilicates with a three dimensional framework structure enclosing pores occupied by cation and water molecules, both of which have considerable freedom of movement within certain limits. The ability of zeolites to exchange cation is one of the mere useful of their characteristics. The ion exchange condition of zeolites strongly affects absorption as well as other properties. The application, techniques of identification and evaluation of clinoptilolite, chabazite, mordenite and phillipsite are reviewed.

• The Journal of Natural Sciences
• /
• v.6 no.1
• /
• pp.103-108
• /
• 1993

Zeolites were discovered as a natural mineral more than two hundred ago. In the beginning, the mineral was used as ion-exchange material and adsorbent. After the end of World War II , however, a variety of zeolites have become available in large amounts because of the establishment of low temperature synthesis and the discobery of natural zeolite deposits of sedimentary origin. Various uses of xeolite were developed utilizing the unique crystal strucrure and function of these minerals. In connection with this development remakable progress has also been made in basic stuides on the related geology and mineralogy, crystallization from sols and gels, structure, ion exchange, adsorption and cataiysis. As a result, zeolites, which had been known only as mineral specimens displayed in museums. established a firm position among the high-technology masterials with excellent functional capabilities.