Molecular sieve manufacturer explains the characteristics of molecular sieves

Molecular sieve is a synthetic hydrated aluminosilicate (foam zeolite) or natural zeolite with molecular sieving function. , calcium ions, barium ions, etc. Next, molecular sieve manufacturer will introduce the characteristics of molecular sieves in detail.

Molecular sieves have the network structure of natural or synthetic chemicals, such as cross-linked dextran, zeolite, etc. When used as a chromatographic medium, the mixture can be fractionated according to molecular size. There are two types of molecular sieves: natural zeolite and synthetic zeolite, large Most natural zeolites are formed by the reaction of volcanic tuff and tuff sedimentary rocks in marine or lake environments. There are more than 1,000 kinds of zeolite minerals that have been discovered, among which 35 are more important. The common ones are clinoptilolite, mordenite, chabazite, etc. They are mainly distributed in the United States, Japan, France and other countries, and a large number of them have also been found in my country. Mordenite and clinoptilolite deposits, Japan is a country with a large amount of natural zeolite mining. Due to the limited natural zeolite resources, synthetic zeolite has been widely used since the 1950s.

Commercial molecular sieves usually use prefix codes to classify molecular sieves with different crystal structures, such as 3A and 4A molecular sieves, 4A type is the type a on the table, the pore size is 4, and the sodium a type molecular sieve is named na-a. If k is used instead of Na, the molecular sieve with a pore size of about 3 is a powdery crystal with metallic luster, a hardness of 35, and a relative density of 22.8. Natural zeolite is colored, while synthetic zeolite is white and insoluble in water. Thermal stability and acid resistance increase with the increase of silica/alumina composition ratio. Molecular sieve has a large specific surface area, up to 3001000m2/g, and its inner crystal surface is highly advanced. It is an efficient adsorbent and a surface acid. Solid acid with high concentration and high strength can cause carbocation catalytic reaction. When the metal ions in the composition are exchanged with other ions in the solution, its adsorption and catalytic properties can be changed by adjusting the pore size, thereby preparing Molecular sieve catalysts with different properties.