Molecular sieves (also known as synthetic zeolites) are aluminosilicate microporous crystals. It consists of a basic skeleton structure composed of silicon oxide and aluminum oxide tetrahedron. Metal cations (e.g., Na+, K+, Ca2+, Li+, etc.) are present in the crystal lattice to balance excess negative charge in the crystal.
The types of molecular sieves are mainly divided into crystal structures: type A, type X and type Y.
Adsorption is a physical phenomenon in which gaseous and liquid substances (adsorbed substances) are immobilized on a solid surface (adsorbent).
The solid (adsorbent) has a large amount of microporous active surface, and the adsorbed molecules are attracted by the surface of the adsorbent. Therefore, the character is fixed on it. The size of gravity depends on:
Structure of the adsorbent surface (micropores);
Partial pressure of the adsorbate;
Adsorption is accompanied by an exotherm and is a reversible phenomenon. Similar to condensation:
If you increase the pressure. Increase adsorption capacity;
Reduce the temperature and increase the adsorption capacity.
Therefore, when adsorbed, the pressure rises to the highest and the temperature is minimized.
At desorption, the pressure is reduced to a minimum and the temperature is raised to the highest.