Molecular Sieves – A Better Understanding
A lot has been written about molecular sieves and their role in keeping moisture away from packed items and industrial operations. At both these places and more, molecular sieves work around-the-clock to remove excess vapour molecules from the surroundings so that the packed items are not affected by water vapour. Molecular Sieves are available in the market in three forms- bead, balls and granular. All these forms of molecular sieve have uniform sized pores, which allow the passage of only same-sized molecules (water vapour) and stop impurities from passing through. There are two major benefits of using molecular sieves as a desiccant. One, as mentioned above, the uniform-sized pores and second, the large surface area. While the same-sized pores attract the molecules, the big surface area ensures that more moisture molecules are absorbed over more domains.
Molecular Sieves- Their Structure, Composition
Now let us take a closer look at the structure and composition of molecular sieves. The pore size of Molecular Sieves are usually measured in angstroms. Depending on the pore size, molecular sieves are graded into various categories. These include 3A, 4A. 5A, 10A and 13 X. All these various grades of molecular sieves have different purposes, depending on their pore size. Among molecular sieves, desiccants having pore size of less than 2 nanometres or 20 Angstrom are known as microporous materials. Macroporous materials are those molecular sieves having pore diameter of more than 50 nm. This is equal to 500 Angstrom.
Molecular Sieves have another category as well- mesoporous. This includes sieves having pore diameter between 2-50 nanometres. Silicon dioxide is one of the molecular sieves coming under this category. Examples of microporous materials are zeolites, active carbon, clay and porous glass. Macroporous materials include mesoporous silica having pore size between 200 and 1000 Angstrom.
Uses of Molecular Sieves
Molecular Sieves have many applications. The major one being in the storage and packaging industry for the removal of moisture from the surroundings so that the packed items are not affected by the presence of vapour molecules. Another field where Molecular Sieves are widely used is the petroleum industry. Here the molecular sieve is used to dry gas streams. The presence of moisture in gas streams can lead to ice formation and corrosion so Angstrom molecular sieve is used to maintain proper moisture levels in the gas streams. As molecular sieves are known to the better drying agents, it is highly recommended to buy high quality molecular sieve products from suppliers like Sorbead India.
Molecular sieve finds use in the laboratory for chromatography purposes like drying solvent. Molecular sieves are used for a wide range of catalytic applications. They form the stationary phase of the chromatography process, which absorbs the different components of any given mixture. The chromatography process is used to catalyze isomerisation, alkylation and epoxidation. In industries, it is used for processes like hydrocracking and fluid catalytic cracking. This is one of the main reasons why Molecular Sieve exporters cater to high demand from other countries.