What is the Difference Between Molecular Sieve and Desiccant?

Ⅰ. What is the molecular sieve desiccant?

Some people may think that the two are the same thing. This is because there is a substance that we call the molecular sieve desiccant. It is a synthetic desiccant and has a strong adsorption effect on water molecules. The pore size of the molecular sieve is controlled by different processing techniques. In addition to absorbing water vapor, it can also absorb other gases. Under high temperature conditions above 230°C, water molecules can still be maintained well. But molecular sieve and desiccant are two substances once they are separated, so what is the difference between these two substances?

Ⅱ. The difference between molecular sieve and desiccant

1. Desiccant

Also called absorbent, it is often used for moisture prevention and mildew prevention with a drying effect. According to different adsorption methods and reaction products, it is divided into physical adsorption desiccants and chemical adsorption desiccants.

2. Molecular sieve powder

is a kind of chemical substance with network structure, which is artificially synthesized. Most of its form is crystalline silicate or aluminosilicate. The pores and cavity system of molecular size are formed by silicon-oxygen tetrahedrons or aluminum-oxygen tetrahedrons connected by oxygen bridges, which has the characteristics of sieving molecules, but its viscosity is very small, the particles are also small, and it is like powder. Therefore, in order to facilitate recycling and processing, adhesives are often added. However, the adhesive will affect the performance of molecular sieve powder. How to reduce the amount of adhesive and increase the proportion of molecular sieve is the key technology for molecular sieve molding.

Add a small amount of alumina and an appropriate amount of dilute nitric acid to form. This method can be the same as other methods. For example, adding silica sol, aluminum sol or titanium aluminum glue. Add nitric acid and water to diluted water hydroxylated alumina with strong binding force to partially dissolve the alumina on the molecular sieve. Sesbania powder generally used is also practical.