What is Absorption and Adsorption? And Their Differences

Absorption and Adsorption are quite important in various applications. Although Absorption and Adsorption sound similar, but they are not the same. One substance gets integrated into the internal structure of another one by the process of absorption, becoming a permanent part of the absorbing material. On the contrary, adsorption is a phenomenon near the surface of a solid or liquid where chemicals adhere and form a thin layer without really entering the bulk of the material.

What is Absorption?

A solid or liquid substance’s bulk phase can be joined by electrons, molecules, or ions by the physical, chemical or biological process of absorption. It is the procedure by which one substance is absorbed and incorporated into the structure of another substance. Typically, this process involves the penetration or diffusion of particles or molecules into the inner workings of the absorbing material.

For Example-

• In biology, it refers to how nutrients are taken up by living things.
• Absorption in chemistry can refer to the dissolving of gases in liquids.

What is Adsorption?

The compliance of molecules to the surface of a solid or liquid is known as adsorption. Only the surface of the adsorbing substance experiences the molecules accumulation. It is the process through which molecules or particles stick to a solid or liquid’s surface as opposed to being taken into the material’s bulk. Basically, it is the process by which molecules or particles are drawn to the adsorbent’s surface.

For Example-

• Adsorption is a term frequently used in environmental science and chemistry to describe the binding of gases or molecules of solutes to the surface of carbon fibre, zeolite or other adsorbent materials.
• For catalytic process, it is the process by which reactant molecules adhere to a catalyst’s surface to start chemical reactions.

Difference Between Absorption and Adsorption

The difference between Absorption and Adsorption are discussed below in a table format:

Parameters	Absorption	Adsorption
Rate of Reaction	It is a endothermic process.	It is a exothermic process.
Phenomenon	It is bulk phenomenon.	It is a surface phenomenon
Temperature	No effect of temperature on the process.	This process occurs at low temperature.
Pressure	It is not dependent on pressure.	It is dependent on pressure.
Concentration	It remains same throughout the process.	It first increases and then come in a state of equilibrium.

Conclusion

To conclude, one can easily differentiate between the processes of absorption and adsorption. The main difference lies in the degree of contact and the type of the process between absorption and adsorption. Different applications and their results can be found in chemistry, the study of materials and environmental science and many other fields of study.