Why Choose Molecular Sieves for Water Removal
Molecular sieve is a silica-aluminate. It consists mainly of silica-alumina connected by oxygen bridges to form a hollow skeleton structure. In the structure there are many pore channels of uniform pore size and neatly arranged cavities with a large internal surface area. It also contains metal ions with low electrical valence and large ionic radius and water in the chemistry state.
Since water molecules are continuously lost after heating, but the crystal skeleton structure remains unchanged, many cavities of the same size are formed. The cavities are in turn connected by many micropores of the same diameter. The molecules of substances smaller than the diameter of the pores are adsorbed inside the cavities, while the molecules larger than the pores are excluded. Thus, molecules of different sizes and shapes are separated. Because it plays the role of sieving molecules, it is called molecular sieve.
Molecular sieve has a strong ability to absorb moisture, so it is widely used as a desiccant. It is used for the purification of gases and should be kept away from direct exposure to air. The amount of molecular sieve dehydration added depends on the water content of the product, the adsorption amount of molecular sieve is larger, generally the adsorption amount is 22% .
The amount of water added to the molecular sieve depends on its moisture content. The adsorption capacity of molecular sieve is relatively large. The general adsorption amount is usually 22%.
Why choose molecular sieve to remove water?
1. Uses.
Molecular sieve has selective adsorption, can de organic solvent and gas in the water. And no adsorption of solvents and gases. Such as tetrahydrofuran.
The original dehydration method is the use of caustic soda. Caustic soda is soluble in water, so it is not easy to separate from tetrahydrofuran after dehydration. Caustic soda is not easy to recycle after use, which invariably increases the cost.
2. Operation.
Molecular sieve dehydration operation is relatively simple, you can directly put the molecular sieve into the solution to be dehydrated, or directly let the solution, gas flow through the molecular sieve adsorption tower.
3. The amount of adsorption.
Molecular sieve adsorption capacity is large, the general adsorption capacity of 22% .
4. Selective adsorption.
Molecular sieve is very easy to adsorb polar water molecules. The diameter of water molecules is smaller than the pore diameter of the molecular sieve, after the adsorption of water molecules and molecular sieve up to electrostatic equilibrium (molecular sieve does not adsorb the diameter of the sub larger than its pore diameter). The whole adsorption process is a physical reaction, will not produce any chemical reaction with the material to be removed.
5. No hydrolysis reaction.
Molecular sieve will not release the absorbed water at room temperature after adsorption.
6. Regeneration.
The regeneration of molecular sieve is relatively simple, the molecular sieve drum more than 300 ℃ nitrogen (non-flammable materials can be directly drummed into the air), one hour after the molecular sieve can be used again.
7. The use of long life.
Molecular sieve can generally be regenerated and used for 3-5 years.
In summary, molecular sieve water has a wide range of uses, simple operation, large adsorption capacity, good selection of adsorption, does not produce water analysis, can be recycled for a long time and other advantages.