The process of separating a crystalloid, from a colloid by filtration, is called

Crystalloid size -   < 1nmcolloid size - 1nm to 1000nmWhen colloids containing crystalloid impurities(generally ionic) are taken in a dialyser basekept in water. Due to the polar nature of water only crystalloids penentrate out of the bagleaving behind colloidal sol particles having large size.                                           The porous dialyser base allows only crystalloids (true solution particles)to pass through it.  The process is called Dialysis, If  electrodes are kept in water the processgets accelarated. This is called Electrodialysis