IIT-M’s cheap solution to make brackish water into potable Water

IIT-M has come up with an idea to convert brackish water into drinking water at about 12 paisa per litre right on the kitchen table by using a potential difference of just 1.8 volts.

How this was made possible?

The researchers used a stack of tissue paper and carbonised it at high temperature to make graphene. Graphite electrodes were then coated with the graphene produced in the lab.

• When the electrodes are dipped into brackish water and 1.8 volt potential is applied to the electrodes, the sodium and chloride ions move towards respective electrodes and get adsorbed.
• In about five minutes, the brackish water turns into potable water with less than 500 parts per million (ppm) of sodium chloride, which is less than the permissible limit for drinking water.
• To render the graphene porous, silica precursors were added to the graphene and removed subsequently. The removal of silica makes the graphene porous while retaining its structural integrity.