Molecular sieves are synthetically produced desiccants with small holes to block large molecules. They are usually used as absorbents of gases or liquids. They are quicker in absorbing water than silica gel. The sieves may be microporous, macroporous and mesoporous. They provide protection against moisture and water. These desiccant molecular sieves are available in beads and pellets. The sieves are in crystalline structure with different pore sizes. They are uniform in their structure, and hence will not let out the moisture back in to the container very easily. They are used in removing water from liquids and gases. They usually consist of zeolite. Zeolite is more effective in removal of water than silica gel, calcium or clay. It also retains moisture even at high temperatures. Hence it is the most preferred desiccant.

The molecular sieve for hydrogen purification process, used according to their pore size in different types of gas drying, gas separation, gas purification and gas dehydration. The different sized sieves are used in different process like ethanol drying, oil purification, olefin drying, drying jet fuel, drying liquefied petroleum gas, drying refrigerants, dehydration of methane and ethylene.

They have various molecular sieve applications including hydrogen purification, natural gases removal, natural gas separation, natural gas dehydration, oxygen removal, oxygen separation, carbon dioxide removal, carbon dioxide separation, natural gas purification, Mercaptan removal, Hydrogen purification, oil purification, solvent drying and air drying. It is used in many industries such as oil and gas, petrochemicals, sugar and air Industries.