Question

What is peptization and coagulation?

Answer 1

Colloidal dispersion is a homogeneous system which is made up of a dispersed phase and a dispersion medium. The dispersed phase is a phase in a two-phased system. It includes colloidal particles. Dispersion medium is the other phase in the two-phased system.

Complete answer:
Peptization and coagulation are two chemical processes that can be mainly observed in colloidal dispersions. Peptization is the formation of a colloidal dispersion from a precipitation. Coagulation is the formation of aggregates from oppositely charged particles which are then settled down under gravity.
The main difference between peptization and coagulation is that peptization involves the breakdown of a precipitate in order to form colloids whereas coagulation includes the formation of aggregates in colloidal dispersions.
Now, what is Peptization?
Peptization is the formation of stable colloids in a dispersion medium. This results in a colloidal dispersion. Peptization involves peptizing agents. It is an electrolyte which is used to pass a precipitate into colloidal particles. Peptization happens since the electrolyte can attract the particles of the precipitate and then the particles can get separate from each other due to electrostatic repulsion. This process is known as peptization.
What is Coagulation?
Coagulation is the gelling or clumping of particles. Typically coagulation takes place in colloidal suspensions. Coagulation happens when unstable particles are present in a mixture. The stability of a colloidal dispersion is dependent on the electrical charges that the particle carries with them. An imbalance of these charged particles can cause the coagulation of particles in order to stabilize the system by balancing the charges.
Here the particles get accumulated to form aggregates then these aggregates settle down in the container under gravity. This process is known as coagulation.

Note:
a precipitate of silver iodine can be peptized by shaking it with a dilute $KI$ solution. Peptization is also used in the production of nanoparticles here the electrolyte can separate large precipitates into smaller colloidal particles which can be further separated into nanoparticles via other advanced methods.
Electrophoresis can be used. Here, the charged particles are focused to move towards the oppositely charged particles. Then those particles form aggregates that can settle down under gravity. If not this can be simply done by mixing two sols having oppositely charged particles.