Difference Between Adsorption and Absorption for JEE Main 2024

Absorption is the process where the fluid is dissolved by a solid (absorbent) or a liquid. Whereas, Adsorption is the process in which ions, molecules, or atoms from a substance (the substance could be a dissolved solid, liquid, or gas) adhere to the surface of an adsorbent. Adsorption is completely a surface-based process, where an adsorbate film is created on the surface; on the other side, the absorption involves an entire volume of the absorbing substance.

Let us discuss in brief on both Adsorption and Absorption in detail, including their differences:

What is Adsorption?

Adsorption is the adhesion of molecules (or atoms and ions) to the surface of a liquid or a solid. Also, the molecules only get accumulated at the surface and do not enter the bulk of an adsorbing material.

• The substance in which the molecules get adsorbed at the surface is known as the adsorbate.

• The substance in which the surface of the process occurs is known as adsorbent.

• It is a surface phenomenon.

Examples of Adsorbents

A few examples of good adsorbents are listed below:

• Silica gel

• Alumina gel

• Activated carbon

• Zeolites

• Graphite

What is Absorption?

Absorption is either a physical or chemical effect or even a mechanism, where molecules, electrons, or ions join some bulk phase of either a solid or liquid substance. It is a differential mechanism from adsorption due to the molecules undergoing absorption soaked up by the length, not by the air. Adsorption is completely dependent on the surface, where an adsorbate film is developed on the surface, and also the absorption includes the complete volume of the absorbing agent.

Mechanism of Adsorption

The adsorption process arises because of the fact that the forces acting on the surface particles of a substance are not similar to that acting on the bulk of the material. Unlike the particles present inside the bulk, on the exposed surface, the particles are not surrounded by the atoms on all the sides.

The forces, consequently, on the inside, balance each other, whereas those exist on the surface are unbalanced. The unbalanced residual forces present on the surface have the tendency to attract the adsorbate particles, and this leads to the process of adsorption.

It is to make a note here that, at a given pressure and temperature, the greater the surface area of adsorbent, the higher is the adsorption extent.

Differences between the Adsorption and Absorption

Let us discuss the essential differences between the terms Adsorption and Absorption, as tabulated below.

Adsorption and Absorption Examples

Examples of Absorption

To distinguish between adsorption and absorption examples are given below:

Skin Absorption

• Skin absorption is the method of taking in substances through the skin surface either into circulation or just into the skin.

• It provides a route for the chemical entry into the body, either as medication or toxins.

Absorption Refrigerators

• The absorption refrigerators are a special type of refrigeration system, which utilizes the absorption concept for the cooling of substances.

• These refrigerators evaporate the refrigerant liquid first, which is absorbed by another liquid than in creating low partial pressure.

Adsorption Examples

Adsorption of Viruses

• At the time of viral infections, the first step in viral replication is the adsorption and attachment of the virus on the organism's surface.

• This is achieved when the specific proteins present on the viral capsid bind to the receptors on the organism's surface.