How can we remove temporary as well as permanent hardness of water by permutit process?
Temporary hardness is caused by dissolved calcium hydrogencarbonate (which is removed by boiling). Permanent hardness is caused by dissolved calcium sulfate (which is not removed by boiling). Water can be softened using washing soda or an ion-exchange resin.
The so-called permutite process is a zeolite based ion-exchange resin, you replace the calcium ions in the water by adding sodium ions to the water. You need to do reading on watersoftening.
The permutit process, also known as ion exchange, is commonly used to remove both temporary and permanent hardness from water. Here's an explanation of how this process works:
1. Understand the concept: Hardness in water is caused by the presence of calcium and magnesium ions. Temporary hardness can be removed by the process of boiling since it converts the bicarbonate ions into insoluble carbonate compounds. On the other hand, permanent hardness is caused by the presence of calcium and magnesium sulfates or chlorides, which cannot be removed by boiling alone.
2. Use ion exchange resin: The permutit process utilizes a special type of resin called ion exchange resin. This resin consists of small beads that are coated with sodium ions (Na+). As water flows through the resin, the calcium and magnesium ions in the water are exchanged with the sodium ions on the resin. This exchange process effectively removes the hardness ions from the water.
3. Regeneration of the resin: Eventually, the resin becomes exhausted as it becomes saturated with calcium and magnesium ions. To restore its capacity, the resin must be regenerated. This is achieved by passing a strong brine solution (sodium chloride - NaCl) through the resin bed. The sodium ions from the brine solution displace the calcium and magnesium ions that have accumulated on the resin. This step replenishes the resin with sodium ions, making it ready for the next round of ion exchange.
4. Continuous operation: The permutit process is usually set up in a series of columns or tanks. As water passes through these columns, it comes into contact with the ion exchange resin, and the hardness ions are removed. Meanwhile, the exhausted resin is regenerated in a separate tank using the brine solution. The regenerated resin is then reintroduced into the treatment process.
Overall, the permutit process effectively removes both temporary and permanent hardness from water by utilizing ion exchange resin. It is a widely used and reliable method for water softening.