The main components functions of molecular sieves are briefly introduced
Molecular sieves have synthetic aluminosilicate hydrate (zeolites) natural zeolites. Its chemical formula is (m'2m) O · Al 2O 3 · xsio2 · yh2o, M ' m are k, Na ca22, ba22 other monovalent divalent cations. There are many uniform holes well arranged holes in the structure. Molecular sieves with different pore sizes can separate molecules of different sizes shapes. According to the molecular ratio of silica to alumina, the molecular sieves with different pore sizes were obtained. Its models are: 3A (potassium a), 4a (sodium a), 5A (calcium a), 10z (calcium z), 13z (sodium z), y (sodium y), mercerizing sodium, etc. It has high adsorption capacity, high selectivity high temperature resistance. It is widely used in organic chemical industry, petrochemical industry other fields.
The basic structure of the framework of molecular sieve is SiO4 alo4 tetrahedron. They combine with a common oxygen atom to form a three-dimensional network structure. This combination forms cavities pores with molecular level uniform pore size. Due to the different structures forms of "cage" space pores, they are divided into "cage" space pores, such as α, β, γ, hexagonal columns pumice.
Adsorption function: the adsorption of molecular sieve to the material comes physical adsorption (van der Waals force). The crystal pore has strong polarity Coulomb field, has strong adsorption ability to polar molecules such as water unsaturated molecules.
Screening function: the pore size distribution of molecular sieves is very uniform, only materials smaller than the pore size can enter into the lattice.
Molecules of different substances are distinguished according to the order of priority adsorption size, so they are appropriately called "molecular sieves".
Molecular sieves have strong hygroscopicity can be used to purify gases. Avoid direct exposure to air during storage. Molecular sieves with long storage time good hygroscopicity should be regenerated before use. Molecular sieves avoid oil liquid water. Avoid contact with oil liquid water during use. 4. The drying gases in industrial production include air, hydrogen, oxygen, nitrogen argon.
