Application of structure properties of 4A zeolite, 3A zeolite and 5A zeolite

When more than 60% of sodium ions in 4A zeolite molecular sieve is replaced by potassium ions, it is called 3A zeolite molecular sieve. When more than 70% sodium ions in 4A zeolite molecular sieve is replaced by calcium ions, at this time called 5A zeolite molecular sieve. Therefore, 4A molecular sieves are the basic raw materials for the preparation of 3A and 5A molecular sieves. 

Each oxygen atom in the skeleton of 4A zeolite is shared by two adjacent tetrahedrons. This structure can accommodate the internal holes of substances such as cations and water molecules, and these cations and water molecules have greater mobility, cation exchange and reversible dehydration can be carried out.

The ion exchange of 4A zeolite is carried out on the skeleton with aluminum ions, each aluminum ion with a negative charge, not only can combine with sodium ions, but also can combine with other cations.

Such as calcium, magnesium ions can enter the original sodium ions occupied by the big hole, the sodium ions in 4A zeolite replaced, that is, the sodium ions in 4A zeolite can be ion exchange, can be exchanged with Ca2+ and Mg2+ in hard water, so as to achieve the purpose of softening water quality.

Although the speed of 4A zeolite binding calcium and magnesium ions than sodium tripolyphosphate (STPP) is slow, and the binding ability with magnesium ions is weak, but 4A zeolite can be a small amount of harmful heavy metal ions such as Pb2+, Cd2+, Hg2+ in aqueous solution is easy to quickly remove, has a very important significance to purify water quality.