Arun
Last Activity: 5 Years ago
Hardness is defined as the soap consuming capacity of a water sample. Generally, soaps consist of the sodium salts of long fatty acids (such as oleic acid, palmic acid and stearic acid). The soap consuming capacity of a water largely due to the presence of Ca+2 and Mg+2 ions as they form insoluble scums of calcium and magnesium soaps which do not have any detergent value.
For softening of water by zeolite process, hard water is percolated at a specified rate through a bed of zeolite. Zeolite holds sodium ion loosely and can be represented as Na2Z, where Z represents insoluble radical frame work.
When the water passes through the zeolite the hardness causing ions (Ca+2, Mg+2 etc.) are retained by the zeolite as CaZ and MgZ respectively, while the outgoing water contains equivalent amount of sodium salts. The block diagram and chemical reactions taking place in zeolite softener are:
Ca(HCO3)2 + Na2Z ® CaZ + 2NaHCO3 Mg(HCO3)2 + Na2Z ® MgZ + 2NaHCO3 CaSO4 + Na2Z ® CaZ + Na2SO4 CaCl2 + Na2Z ® CaZ + 2NaCl MgSO4 + Na2Z ® MgZ + Na2SO4 MgCl2 + Na2Z ® MgZ + 2NaCl | |