Question

What is flocculation?

Answer 1

Hint: Flocculation: It is defined as the process in which colloids come out of suspension in the form of flake. The flake formed due to the flocculation process may float to the top or may settle to the bottom of the liquid.

Complete step by step solution:
Colloidal mixtures: It is defined as the mixture in which the tiny particles are suspended throughout another substance.
Dispersion phase: The phase in which the colloidal particles exist, are known as dispersed phases.
Dispersion medium: The medium in which the colloidal particles are distributed, is known as dispersion medium.
Colloid mixtures are of many types based on the size of dispersed phase:
Multi-molecular colloids: The solutions which are formed due to large numbers of atoms or small molecules, are known as multi-molecular colloids. For example: Gold sol, sulphur sol.
Macromolecular colloids: The solutions which form heavy molecules, are known as macromolecular colloids. For example: starch, proteins.
Associated colloids: Those solutions which behave as strong electrolytes at lower concentration but show colloidal properties at higher concentration, are known as associated colloids. For example: micelles.
Now, let us first read about coagulation, flocculation.
Coagulation: It is defined as the process in which chemicals are added which causes small particles to bring together to form large molecules. Colloidal solution is stable due to presence of charge. So the electrostatic force of repulsion between the same charges prevents the coagulation (binding up of particles) of particles. If we remove the charge then there will be no repulsion between the particles. Hence they will come closer and aggregate to form large molecules. And they form, coagulate or precipitate.
Flocculation: It is defined as the process in which colloids come out of suspension in the form of flake. The flake formed due to the flocculation process may float to the top or may settle to the bottom of the liquid.
Coagulation and flocculation both the processes are used to separate the suspended solids particles from the water. Suspended particles may have different size, charge, etc.

Note: We know that the same charge repels each other and opposite charges attract each other. The extent of force is known as electrostatic force of attraction in case of opposite charges and electrostatic force of repulsion in case of same charge.