Describe the purification of colloidal solutions by the phenomenon of dialysis with a neat diagram.

Dialysis: The process of removing a dissolved substance from a colloidal solution using a suitable membrane is called Dialysis.
Purification method: A bag of suitable membrane containing the colloidal solution is suspended in a vessel containing a continuously flowing water. The molecules and ions diffuse through the membrane into the water and pure colloidal solution is left behind in the bag.
The apparatus used for this purpose is called as Dialyser