9.23 Discuss the principle and method of softening of hard water by synthetic ionexchange resins.
The treatment process of permanent hard water using synthetic resin is based on cations exchange and anion exchange ;present in water by ions and ions.
There are two types-
(i) Cation exchange resins
(ii)anion exchange resins
Cation exchange resin is large organic molecules contain group and are water-insoluble. Ion exchange resin (RSO3H) is changed to RNa by treating it with NaCl. The resin exchanges ions with and ions present in hard water to make the water soft.
There are cation exchange resins in H+ form. The resins exchange H+ ions for Na+, Ca2+, and Mg2+ ions.
Anion exchange resins exchanges ions for anions like
Water first passes through the cation exchange process. The water obtained is acidic in nature and this acidic water then passed through anion exchange process where ions neutralize the H+ ions