Question

Write a note on zeolites.

Answer 1

1. Zeolites are three-dimensional crystalline solids containing aluminium, silicon and oxygen in their regular three-dimensional framework.
2. They are hydrated sodium alumino silicates with general formula, Na₂O. (Al₂O₃). x(SiO₂)y(H₂O) (x = 2 to 10; y = 2 to 6)
3. Zeolites have a porous structure in which the monovalent sodium ions and water molecules are loosely held.
4. The Si and Al atoms are tetrahedrally coordinated with each other through shared oxygen atoms.
5. Zeolites structure looks like a honeycomb consisting of a network of interconnected tunnels and cages.
6. Zeolite crystals act as a molecular sieve. They help to remove the permanent hardness of the water.