Molecular sieve (also known as synthetic zeolite) is a kind of silica-aluminate multiporous crystal. It is a basic skeleton structure composed of silicon and aluminium oxide tetrahedrons. Metal cations (such as Na+, K+, Ca2+, Li+) exist in the lattice to balance the excess negative charges in the crystal. Molecular sieves can be classified into A type, X type and Y type according to their crystal structure.

Chemical Formula of Zeolite Molecular Sieve Cells: Mx/n[(AlO 2)x(SiO 2)y]-w H 2 O 2

purpose

Mainly used in automobile, building glass, medicine, paint and coating, packaging and other fields.

Storage

At room temperature, the relative humidity is not more than 90% indoor: avoid water, acid, alkali, air isolation, sealed storage.

performance

Molecular sieves are powder crystals with metallic luster, hardness 3-5, relative density 2-2.8, natural zeolites have color, synthetic zeolites are white, insoluble in water, thermal stability and acid resistance increase with the increase of SiO 2/Al2O3 composition ratio. Molecular sieves have a large specific surface area of 300-1000m2/g, highly polarized inner crystal surface. They are a kind of highly efficient adsorbent and solid acid. Their surface has a high acid concentration and acid strength, which can cause positive carbon ionic catalytic reaction. When metal ions are exchanged with other ions in the solution, the pore size can be adjusted, and the adsorption and catalytic properties can be changed to prepare zeolite catalysts with different properties.

classification

Commercial molecular sieves are usually classified by prefix digits, such as 3A, 4A and 5A molecular sieves. Type 4A is Class A in the table with 4_aperture. Type A zeolite containing Na + is designated as Na-A. If Na + is replaced by K +, the pore size is about 3, that is, type 3A zeolite. For example, more than one third of Na + in Na-A is replaced by Ca2 +, and the pore size is about 5; that is, type 5A zeolite.