The role of zeolite molecular sieves

The zeolite molecular sieves is heated to about 200 ℃ water to evaporated, to obtain activated zeolite, porous sponge is formed, so that the cation exchange properties of adsorption and to play. And when the water is heated to escape, more open channels and cavities, corresponding to greater internal surface area, and inside the zeolite crystal cave after dehydration with strong Coulomb field and polarity, plus dispersion forces and static electricity and makes zeolite showed a strong adsorption.
3a zeolite molecular sieves has a high temperature properties, but the temperature is too high will destroy its structure so that it loses ion exchange. Under normal circumstances, the ignition 500 ℃ ~ 550 ℃ can improve the mechanical strength of the pore volume can be increased to increase the specific surface area, but also increase locomotor activity cation ion exchange is more fully.
Depends on the thermal stability of the natural zeolite of silicon, aluminum, and the balance 13x zeolite molecular sieves cation ratio, generally within the range of variation in the composition, the high silicon content, the better the stability. Some changes in the balance of cationic nature, for the stability of the crystals have a significant impact, such as calcium-based natural clinoptilolite can decompose below 500 ℃, if the same sample with potassium ion exchange, it is still crystal temperature of 800 ℃ destruction.

Zeolite molecular sieves

Zeolite molecular sieves a crystalline aluminosilicate hydrate of metal, and its chemical formula is:
Mx / m [(AlO2) x  (SiO2) y]  zH2O. M represents a cation, m represents the number of valence, z is a hydration number, x and y are integers. After the activation of zeolite, water molecules are removed, and the remaining atoms to form a cage-like structure, a pore diameter of 3 ~ 10Å.5a zeolite molecular sieves crystals have a number of holes with a diameter (also called "windows") are connected between the plurality of holes of a certain size, a hole. Due to its pore molecular sieve adsorption ratio can small molecules to the internal cavity, and the pore size larger than the hole in its rejection of foreign molecules, molecules play a role in screening, so named sieve.
13x zeolite molecular sieves pores or channels in their system can be divided into the hole, the hole (mesoporous) and holes zeolite three groups.
PSA oxygen-enriched air can be used for adsorption separation.

molecular sieves

In 1932, McBain put forward the concept of "molecular sieve" of. Said porous material can be sieved material at the molecular level.molecular sieves msds Although only a zeolite molecular sieve, zeolite, but the most representative, so "zeolite" and "4a molecular sieves" These two words are often mixed.

Analcime

SEM micro-morphological characteristics of a quadrangular three octahedral shape, and various forms of polyethylene, mostly 4,6 polygonal plane, grains can be as large tens mm, EDX spectrum characteristic element of Si, Al, Na, there can be small Ca.

Zeolite general formula

Zeolite general formula: AmBpO2p · nH2O, the formula A (x / q) [(AlO2) x (SiO2) y] n (H2O) where: A is Ca, Na, K, Ba, Sr cationic,

B is Al and Si, p is the valence of the cation, m is the number of cations, n is the number of molecules of water, x is the number of Al atoms, y is the number of Si atoms, (y / x) is generally between 1 ~ 5, (x + y) is the number of tetrahedral unit cell.