Question

Describe the permutit process for softening hard water.

Answer 1

Hard water:

• Hard water is the water which contains salts of calcium and magnesium like sulphates, carbonates, bicarbonates, and chlorides.
• Hard water does not form lather with soap.
• Hard water has a high content of minerals.

Permutit process:

• The process in which hard water containing ${\mathrm{Ca}}^{2+}$ is filtered through sand named zeolite is called the Permutit process.
• Permutit is a zeolite of an artificial source. It is an orthosilicate of sodium aluminium compound with the chemical formula ${\mathrm{Na}}_2{\mathrm{Al}}_2{\mathrm{Si}}_2{\mathrm{O}}_8.{\mathrm{xH}}_2\mathrm{O}$.
• Chemically, it is hydrated sodium aluminium orthosilicate.
• In a high cylindrical vessel filled with gravel sand and permutit, the water softening procedure is done.
• Via an inlet, durable water is added.
• The water enters the vessel’s bottom. The gravel layer carries out the removal of impurities.
• It then comes into contact with permutit, which in tank water substitutes ${\mathrm{Mg}}^{2+}$ and ${\mathrm{Ca}}^{2+}$ ions into ${\mathrm{Na}}^{+}$ ions.

Chemical reaction:

${\mathrm{Na}}_2\mathrm{X}\left(\mathrm{aq}\right)+{\mathrm{Ca}}^{2+}\left(\mathrm{aq}\right)\to \mathrm{CaX}\left(\mathrm{aq}\right)+2{\mathrm{Na}}^{+}\left(\mathrm{aq}\right)$

Where X = ${\mathrm{Na}}_2{\mathrm{Al}}_2{\mathrm{Si}}_2{\mathrm{O}}_8.{\mathrm{xH}}_2\mathrm{O}$