Zeolites are an extremely useful group of minerals characterized by a microporous structure—that is, a structure with minute pores. Chemically, they are alumino-silicate minerals that can lose and absorb water and various ions and gases without damage to their crystal structures.The cations in their pores are generally those of alkali metals (such as Na + and K +) or alkaline earth metals
Natural zeolites occur in mafic volcanic rocks as cavity fillings, probably as a result of deposition by fluids or vapours. In sedimentary rocks zeolites occur as alteration products of volcanic glass and serve as cementing material in detrital rocks; they also are found in chemical sedimentary rocks of marine origin. Extensive deposits of zeolites occur in all oceans.
Natural Zeolite. Natural zeolites form hydrothermally (e.g., by the action of hot water on volcanic ash or lava), and synthetic zeolites can be made by mixing solutions of aluminates and silicates and maintaining the resulting gel at temperatures of 100°C (212°F) or higher for appropriate periods. From: Heavy Oil Recovery and Upgrading, 2019
Natural zeolites have the exceptional quality of ion exchange, incorporating cations such as cadmium, mercury, nickel or arsenic (heavy metals) and releasing calcium, magnesium or phosphates (minerals that are healthy for the human body). This fact makes the natural zeolite used for various natural applications related to agriculture, animal
Zeolites are an extremely useful group of minerals characterized by a microporous structure—that is, a structure with minute pores. Chemically, they are alumino-silicate minerals that can lose and absorb
Zeolite A is a well-known example. Since the main raw materials used in the production of zeolites are silica and alumina, which are the most abundant mineral components in the world, their potential to provide zeolites is almost limitless. Natural occurrence. As of 2016, the world’s annual natural zeolite
A. Dyer, in Encyclopedia of Materials: Science and Technology, 2001. 5 Other Zeolites of Commercial Significance 5.1 Clinoptilolite (HEU) and Mordenite (MOR) Both these zeolites have silica-rich frameworks based on five-oxygen rings linked together: 5–1 for mordenite and 4–4–1 for clinoptilolite (Fig. 1).The structures have lower void volumes than those of zeolites
A. Dyer, in Encyclopedia of Materials: Science and Technology, 2001. 4.2 Synthetic Zeolites X and Y (FAU) Zeolites X and Y form a series of structures which are isostructural with the rare natural
Zeolites: Crystalline, hydrated alkali-aluminumsilicates of the general formula M(2/n)O.Al2O3.ySiO2.wH2O where M represents a group 1A or IIA element, n is the cation valence, y is 2 or greater, and w is the number of water molecules contained in the channels or interconnected voids within the zeolite.
This brief review article describes the structure, properties and applications of natural and synthetic zeolites, with particular emphasis on zeolites obtained from natural or waste materials. Certainly,