Question

What are the methods of removing hardness of water?

Answer 1

The hardness of Water - It is caused due to the presence of minerals in the water like salts of Calcium or Magnesium.

It is of two types -

1. Temporary Hardness - It contains only bicarbonate salts of Magnesium and Calcium. It can be removed by boiling. For example, ${\mathrm{CaHCO}}_3,{\mathrm{MgHCO}}_3$etc.
2. Permanent Hardness - It contains Chlorides and Sulfates salts of Calcium and Magnesium. It cannot be removed by boiling. For example, ${\mathrm{MgCl}}_2,{\mathrm{CaSO}}_4$etc.

Removing of Temporary Hardness - The temporary hardness can be removed by the process like:

1. Boiling - The process of heating any substance at its boiling temperature.
2. Clarks Method - In this method, hard water is treated with Slaked lime or Lime water$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$ to remove temporary hardness.

Removing of Permanent Hardness - The permanent hardness can be removed by the process like:

1. Gan’s Permutit Method - In this method, hardness is removed by using Permutit or Zeolites.
2. Calgon’s Process - In this method, the formation of complex Calgon takes place which helps in ionizing the complex anions from the hard water.
3. Ion Exchange Resin Method - In this method, Sodium ions(${\mathrm{Na}}^{+}$) are used to coat an exchange medium in the softener in order to remove the hardness of water.