A natural or synthetic chemical substance with a network structure. For example, 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.
① Most natural zeolites are formed by the reaction of volcanic tuff and tuffaceous sedimentary rocks in marine or lacustrine environments. At present, more than 1,000 kinds of zeolite minerals have been discovered, of which 35 are more important. The common ones are clinoptilolite, mordenite, erionite and chabazite. Mainly distributed in the United States, Japan, France and other countries, China has also discovered a large number of mordenite and clinoptilolite deposits, and Japan is the country with the largest amount of natural zeolite mining.
②Since natural zeolites are restricted by resources since the 1950s, synthetic zeolites have been widely used. Commercial molecular sieves often use prefix numbers to classify molecular sieves with different crystal structures, such as 3A, 4A, and 5A molecular sieves. Type 4A is type A in the table, with a pore size of 4Å. A molecular sieve containing Na+ is denoted as Na-A, if Na+ is replaced by K+, the pore size is about 3Å molecular sieve is a powdery crystal with metallic luster, hardness of 3～5, relative density of 2～2.8, natural zeolite has color, Synthetic zeolite is white, insoluble in water, thermal stability, and acid resistance increase with the increase of SiO2/Al2O3 composition ratio.
Molecular sieves have a large specific surface area of 300～1000m2/g. The surface of the inner crystal is highly polarized. It is a type of high-efficiency adsorbent and a type of solid acid. The surface has a high acid concentration and acid strength, which can cause normal carbon. Ionic catalytic reaction. When the metal ions in the composition are exchanged with other ions in the solution, the pore size can be adjusted to change its adsorption and catalytic properties, thereby preparing molecular sieve catalysts with different properties.
Carbon Molecular Sieve for Psa Plant:
Product description
The noteworthy feature: Especially at purity lower than 99.5%, get the high efficiency of gas production, low air consumption. Widely used in large-scale air separation plants, applications include coal mining, ships, petroleum storage, and transportation, etc.
