Hollow columnar zeolite molecular sieve adsorbent

Hollow columnar zeolite molecular sieveThe chemical composition formula of molecular sieve is: (M) 2/nO · Al2O3 · xSiO2 · pH2O, where M represents metal ions (usually Na in artificial synthesis), n represents the valence of metal ions, x represents the number of moles of SiO2, also known as the silicon aluminum ratio, and p represents the number of moles of water. The most basic structure of the molecular sieve skeleton is SiO4 and AlO4 tetrahedra, which form a three-dimensional network structure of crystals through the binding of shared oxygen atoms. This combination forms voids and pores with molecular level and uniform pore size. Due to different structures and forms, the "cage" shaped spatial pores are divided into cage structures such as alpha, beta, gamma, hexagonal columns, and octahedral zeolites.

Hollow columnar zeolite molecular sievemolecular sieveIt has many uniformly sized pores and neatly arranged pores in its structure, and molecular sieves with different pore sizes separate molecules of different sizes and shapes. According to the different molecular ratios of SiO2 and Al2O3, molecular sieves with different pore sizes are obtained. Its models include: 3A (potassium type A), 4A (sodium type A), 5A (calcium type A), 10Z (calcium type Z), 13Z (sodium type Z), Y (sodium type Y), sodium zeolite type, etc. It has high adsorption capacity, strong selectivity, and high temperature resistance. Widely used in organic and petrochemical industries, it is also an excellent adsorbent for gas dehydration.

According to their catalytic properties, molecular sieve catalysts can be divided into the following points:

(1) Acid catalysts utilize the surface acidity of molecular sieves for catalytic reactions.

(2) A bifunctional catalyst, molecular sieve, can be loaded with platinum and palladium metals to obtain a bifunctional molecular sieve catalyst that combines metal catalytic and acid catalytic functions.

(3) Shape selective catalysts, due to the fact that the catalytic effect of molecular sieves generally occurs within the crystal space, the pore size and pore structure of molecular sieves have a significant impact on catalytic activity and selectivity. Molecular sieves have regular and uniform intragranular pores, and the pore size is close to the molecular size, which significantly changes the catalytic performance of molecular sieves with the geometric size of reactant molecules, product molecules, or reaction intermediates.