Commercial and Domestic Uses of Zeolites

Since the discovery of zeolites till now, there has been a steady increase in interest in scientific research and the application of this wonderful, interesting, and valuable substance.

Natural zeolites are aluminosilicate materials that have been hydrated. PBUs are tetrahedra of Si and Al oxides that are joined by oxygen ions to form two-dimensional and three-dimensional secondary units (secondary building units [SBUs]). Channels and holes in the zeolite network are filled with hydrated alkali and alkaline earth metal ions. A balance between the positive electric charge of metal ions and the negative charge of the zeolite network is reached when these metal ions are present in the structure of zeolites.

Synthetic zeolites, unlike natural zeolites, which develop as crystals in cavities of basalt rocks or as volcanic tuff in various geological contexts at relatively moderate temperatures, are made in a laboratory using hydrothermal synthesis.

Zeolites: 

Zeolites are hydrated aluminosilicate minerals composed of interconnected alumina (AlO4) and silica tetrahedra (SiO4). Zeolites are arranged in a regular pattern and are nearly the same size as tiny molecules made up of cavities referred to as a variety of crystalline formations with wide-open pores. In other words, Zeolites are crystalline inorganic polymers made up of SiO4 and AlO4tetrahedra with a structure loaded with ions and water molecules and have a lot of freedom of movement, as seen in the given figure.

Its chemical formula is as follows :-  

Characteristics of zeolites: 

The unique properties of zeolites are due to their specific structure. 

• Low density and a large volume of free spaces

• The presence of channels and chambers with strictly defined dimensions (shape-selectivity)

• High degree of hydration and the presence of so-called zeolite water.

• High degree of crystallinity Possibility of adsorption of molecules and ions

• Ion exchange capacity

• Catalytic properties

Natural Zeolites: 

Natural zeolites are hydrothermal in nature and primarily volcanic in origin. They can be found in crystallized forms in igneous and metamorphic rocks, as well as in smaller-diameter grains accumulated in sedimentary rocks.

Synthetic Zeolites: 

Zeolites have long been recognized as natural minerals, but there are now over a hundred different types of zeolite structures that may be created synthetically but it in reality took thousands of years of research to complete. In the laboratory, increased temperature or pressure, as well as natural raw materials and/or synthesized silicates, can be used to simulate hydrothermal processes.

General Applications of Zeolites: 

Ion-exchange beds made of zeolites are widely utilized in home and commercial water purification, softening, and other applications. Zeolites are employed in chemistry to separate molecules of various sizes and as traps for molecules that must be examined.

Zeolites have the ability to enable precise gas separation, such as the removal of water, carbon dioxide, and sulfur dioxide from low-grade natural gas streams. Noble gases, nitrogen, freon, and formaldehyde are among the other gases that can be separated. However, the real potential for improving the handling of these gases in this way is currently unknown.

Use of Zeolites in the Commercial sector: 

Catalysis, gas separation, and ion exchange are the three main applications of zeolites in industry.

• As a catalyst: Zeolites are excellent catalysts for a variety of key organic molecular processes. Cracking, isomerization, and hydrocarbon synthesis are the most important. Acid-base and metal-induced reactions are among the catalytic reactions that zeolites can promote.

• As an adsorber: Zeolites are used to adsorb a wide range of compounds. This comprises drying, purification, and separation applications. They can extract the water to extremely low partial pressures and are particularly effective desiccants, capable of holding up to 25% of their weight in water. It can be regenerated as a desiccant after ‘pulling a vacuum’.

• Used in asphalt concrete: In the manufacturing of warm mix asphalt concrete, synthetic zeolite is also employed as an ingredient. This application was first developed in Germany in the 1990s. It aids in the reduction of temperature during the fabrication and laying of asphalt concrete, resulting in lower fossil fuel consumption and lower emissions of carbon dioxide, aerosols, and vapors.

Use of Zeolites in the Domestic sector: 

• The smell and liquid adsorption properties of zeolite are mostly used in domestic applications. Zeolite has been proven to absorb a variety of gases, including formaldehyde and hydrogen sulfide.

• It’s widely used to absorb cigarette odors, dry sports shoes, and minimize moisture in wardrobes. Zeolite was used as the basic material of a very useful carpet cleaner.

• Cat litter and fat absorbers for barbecues are two of the most prevalent uses for zeolite in the home. It’s also used to absorb ammonia in fish tanks. When fully utilized, the discarded product is an excellent addition to composts, where it will help to condition the soil and eventually contribute to moisture and nutrient retention.

Conclusion: 

Both sedimentary rocks containing zeolites and zeolites produced from aluminosilicate raw materials can be regarded as valuable for numerous industries, including agriculture and environmental protection, according to the scientific evidence published in the associated literature thus far. Synthetic zeolites are the most common alternatives for natural zeolites.