Molecular Sieve
Molecular sieve, also known as zeolite, is a porous material capable of selectively adsorbing molecules of a specific size. This substance is frequently used as a desiccant and for the adsorption of gases in various industrial applications.
Porous Structure
Molecular sieves have a large internal surface area because they consist of a lattice of micropores. The size of the pores varies depending on the type of molecular sieve. There are different types of molecular sieves with varying pore sizes and specific applications.
Selective Adsorption
Due to their micropores, molecular sieves can selectively adsorb certain molecules while allowing others to pass through. Only molecules with a smaller diameter than the micropores of the molecular sieve can enter the pores. This makes them useful for applications such as dehumidifying air and gases.
Air Drying
Molecular sieves are often used in desiccant products to dehumidify air or gases. They adsorb water from the air and retain it in their pores.
Zeolite 3A (Molecular Sieve Type 3A)
This zeolite has a pore size of 3 Angstroms (Å) = 0.3 nm, which makes it particularly suitable for adsorbing water molecules. This pore size is too small for solvents to be adsorbed. Zeolite 3A is often used to remove water from air or gases, especially when it comes to protecting sensitive products like medicines.
Zeolite 4A (Molecular Sieve Type 4A)
Similar to Zeolite 3A, Zeolite 4A also has a high affinity for water molecules. It is also frequently used in desiccant products to adsorb moisture from the air and thus protect sensitive goods.
Difference from silica gel
Molecular sieves bind water molecules independently of ambient humidity, i.e., even below 10% relative humidity. However, they have a lower absorption capacity than silica gel. They are used for particularly sharp drying or to protect products at the lowest possible relative humidity of close to 0% within the packaging.