Removal of Hardness of Water by Ion Exchange Column.

Procedure

Follow these steps to determine the Removal of Hardness of Water by Ion Exchange Column

1. Ion Exchange Column: Pass the water sample through the Ion exchange column containing cation exchange resin, discard first few ml of water and then collect the water sample.
2. Standardization of EDTA solution
   (i) In a clean and dry conical flask pipette out 20 ml of standard hard water solution.
   (ii) To this add 5 ml of ammonia buffer solution and then add 2-3 drops of EBT indicator, blue color of EBT changes to wine-red color.
   (iii) Fill the burette with EDTA solution after rinsing, note the initial burette reading. Titrate the solution in the conical flask till the wine red color changes to blue and note the final burette reading.
3. Determination of Total hardness
   Repeat the above titration method for hard water sample before and after passing through the column and note the initial and final burette readings

Safety Precautions:

1. Clamp the burette perfect vertically, so that it is easy to read the scale properly.
2. Before use rinse the burette thoroughly, while filling the burette no air bubble should be present in the burette and dispense off working solution from the burette.
3. Remove funnel after filling burette upto mark zero. Read the lower meniscus of the burette.
4. Add basic buffer (NH4Cl + NH4OH) to maintain the pH =10 during titration. Add ammonia buffer just before starting the titration if you add long before the titration pH of the solution may vary due to evolution of NH3(g) from the solution.
5. Add same number of drops (vol.) of indicator in each titration.
6. To get better visibility of color change at the end point use filter paper below the conical flask.
7. During titration conical flask should be stirred continuously and correctly observe the end point.