What is meant by coagulation of a colloidal solution? Describe briefly any three methods by which coagulation of lyophobic sols can be carried out.
The process of setting of colloidal particles is called coagulation of sol. Coagulation is the destabilization of Colloids by neutralizing
the electric charge of the dispersed
phase particles, which results in aggregation of the colloidal particles.
The coagulation of the lyophobic sols can be carried out by
following methods.
(1) By electrophoresis: In electrophoresis the colloidal particles
move towards oppositely charged electrode. When these come in contact with the
electrode for long these are discharged and precipitated.
(2) By mixing two oppositely charged sols : When oppositely
charged sols are mixed in almost equal proportions, their charges are
neutralised. Both sols may be partially or completely precipitated as the
mixing of ferric hydroxide (+ve sol) and arsenious sulphide (–ve sol) bring
them in precipitated form. This type of coagulation is called mutual
coagulation or material coagulation.
(3) Dialysis: Electrolyte are removed from the sol and colloid becomes unstable and gets coagulated.
The process of setting of colloidal particles is called coagulation of sol. Coagulation is the destabilization of Colloids by neutralizing the electric charge of the dispersed phase particles, which results in aggregation of the colloidal particles.
The coagulation of the lyophobic sols can be carried out by
following methods.
(1) By electrophoresis: In electrophoresis the colloidal particles move towards oppositely charged electrode. When these come in contact with the electrode for long these are discharged and precipitated.
(2) By mixing two oppositely charged sols : When oppositely charged sols are mixed in almost equal proportions, their charges are neutralised. Both sols may be partially or completely precipitated as the mixing of ferric hydroxide (+ve sol) and arsenious sulphide (–ve sol) bring them in precipitated form. This type of coagulation is called mutual coagulation or material coagulation.
(3) Dialysis: Electrolyte are removed from the sol and colloid becomes unstable and gets coagulated.
