Question

What is electrodialysis? Explain with a suitable diagram.

Answer 1

Electrodialysis is an improved method of purifying colloidal solutions (or sols) by removing dissolved electrolyte impurities. It is based on the principle of dialysis, but the process is accelerated using an electric field.

Dialysis is a slow process because it depends on the natural diffusion of ions through a semipermeable membrane. To speed it up, an electric field is applied across the solution. Under the influence of this field, the impurity ions migrate quickly towards oppositely charged electrodes, leaving behind the purified colloidal sol.

This faster method of dialysis is called electrodialysis.