Examples of Colloids

Colloids occur in abundance in nature, and we can also synthetically produce them. Colloids have a broad range of applications; therefore, it is critical to have a comprehensive classification system.  

Colloids are the combination of a dispersed phase and a dispersion medium. We can divide them into groups based on the dispersed phase and the medium features. Let us discover more about them. 

Examples of Colloids 

Many colloidal solutions are all around us. Cake, milk, bread, butter, ice cream, fruit juices, whipped cream, and other foods are examples of colloids. Apart from them, fog, mist clay, and other colloids exist.

Classification of Colloids Based on Type

A colloid is a mixture of two substances with tiny particles blended. The dispersed phase refers to the compounds that have been dispersed in the solution, whereas the dispersion medium refers to the solution wherein they disseminate. 

We can classify colloids based on their types as:

• Multimolecular colloids

• Macromolecular colloids

• Associated colloids

Multimolecular Colloids

The grouping of many atoms plus small molecules produces a dispersed medium solution (with diameters just under 1 nm). The dispersion particles are held together by Van der Waals forces.

Examples include gold sol and sulphur sol.

Macromolecular Colloids

Macromolecules are giant molecules formed when molecules with extremely high molecular weights unite. The colloidal processes are macromolecular colloids when certain substances disseminate in an appropriate dispersion medium. Macromolecular colloids, as a consequence, have a substantial molecular mass.  

The origins of lyophilic colloids are frequently macromolecular. Macromolecular colloids form when natural macromolecules disperse in a solvent system. These macromolecules include nucleic acids, proteins, starch, cellulose, gelatin, etc. Human-made polymers such as synthetic rubber, polypropylene, and polyethylene produce macromolecular colloids.

Associated Colloids

Some colloids function as vital electrolytes at low concentrations but show colloidal properties at more significant concentrations. 

The molecules of the dispersed phase align so that micellar structures develop at a specific concentration, called the critical micellar concentration. Associated colloids are those that produce such micelles.

Classification of Colloid Based on Interaction Between Molecules

We can divide colloids into two types based on how the molecules interact.

Lyophilic Colloids (Solvent-Loving)

In these colloidal solutions, the particles of the dispersed phase and the particles of the dispersed medium have a strong affinity. They are incredibly steady. They are challenging to coagulate and necessitate the use of a solid electrolyte. 

Lyophilic Colloids include gum, starch, gelatin, and proteins. In contrast to lyophilic colloids, hydrophilic colloids use water as a dispersion medium.

Lyophobic Colloids (Solvent-Hating)

In these kinds of colloidal solutions, the particles of the dispersed phase and the particles of the dispersion medium have a weak affinity. As lyophilic colloids, these have reduced stability. It may quickly coagulate on the addition of a small amount of electrolyte. 

Lyophobic colloids include silver sol, ferric hydroxide sol, and arsenious sulphide sol. Lyophilic colloids that use water as a dispersion medium are known as hydrophilic colloids.

Classification of Colloids Based on Dispersion

We can also classify colloids by the phase of the dispersed substance and the medium of its dissemination. Classification of colloidal solutions includes liquids, emulsions, foams, and aerosols.

• Sol is a colloidal dispersion of solid particles in a liquid.

• An emulsion is a mixture of two liquids.

• Foam forms when it traps many gas particles in a liquid or solid.

• Small liquid or solid distributed phases in gas make up aerosols.

Preparation Method

We can generate colloids in two different ways:

Dispersion: It is created by the colloidal dispersion of big liquid droplets or by applying shear (e.g., shaking or mixing).

Condensation: Condensation works by condensing tiny dissolved molecules through condensation and precipitation.

Application of Colloids

Colloids are frequently utilised and also have a wide range of uses. Most of its uses are as follows:

• Bodily tissues absorb colloids. Hence, colloids are used in medicines. Gold sol treats injuries to the human body. Silver sol is a component of eye lotions. Other examples include dextran and hetastarch.

• Soaps contain colloids, which impart cleansing action that eliminates dirt by emulsifying oily materials.

• Colloids are essential in the production of paints and inks. The ink used during ballpoint pens is a liquid-solid colloid.

Colloid Elimination During Water Filtration

The best solution is to do an initial step particle coagulation with just a coagulant agent to eliminate colloids from water. The only goal of destabilising the colloid electrostatic charge from the above step is to facilitate the meeting plus their future agglomeration during the emulsification step.

Certain electrolytes, such as alum, can precipitate colloidal contaminants. The effect of alum neutralises the negative charges of colloidal particles of pollutants.

Conclusion

Colloids are a mixture of two substances in which small suspended particles are above one another. Particles range in size from 0 to 1000 nanometres. Typically, the span is more significant than the particles in the solution. Once the particles of a combination do not settle after being left undisturbed, it is characterised as a colloid.

The Tyndall effect is a phenomenon of colloidal solutions in which a ray of light is dispersed on colloids caused by the interaction between the light and colloidal particles.