Adsorption & Absorption
Below in this article, we discuss the Difference between Adsorption and Absorption.
In Adsorption, the term adsorbate refers to the material whose molecules are adsorbed at the surface. The substance on whose surface the reaction occurs is known as the adsorbent. It is a surface-level occurrence.
Absorption is distinct from adsorption since molecules undergoing absorption are sucked up by the length and not by the surrounding air. Adsorption is based on the surface where a film of adsorbate forms, whereas absorption accounts for the entire volume of the absorbing agent.
What is Adsorption?
Adsorption is the attachment of molecules (or ions and atoms) to the solid or liquid surface. The molecules do not penetrate the bulk of the adsorbing substance and only aggregate at the surface.
- Adsorbate refers to the material whose molecules are adsorbed at the surface.
- The substance on whose surface the reaction occurs is known as the adsorbent.
- It is a surface-level occurrence.
What is Absorption?
Absorption is a physical or chemical effect or mechanism whereby electrons, molecules, or ions combine with a solid or liquid bulk phase.
The Difference Between Adsorption and Absorption
| Criteria | Absorption | Adsorption |
| Definition | Incorporation of the molecular system into the majority of a solid or liquid media. | Accumulation of molecular species at the bottom of a liquid or solid rather than in the liquid or solid. |
| Phenomenon | A bulk phenomenon. | A surface phenomenon. |
| Heat exchange | Endothermic process | Exothermic process |
| Temperature | The temperature has no effect. | Influenced by low-temperature |
| Rate of reaction | Occurs at a uniform rate. | Increases steadily and reaches equilibrium. |
| Concentration | It is constant throughout the medium. | Concentration at the adsorbent’s base differs from that in the bulk. |
Examples of Adsorbents
- Some examples of good adsorbents include:
Alumina gel - Silica gel
- Zeolites
- Activated carbon
- Graphite
What is Desorption?
Desorption is the opposite of adsorption, in which the adsorbed substance is removed from the adsorbent’s surface.
Mechanism of Adsorption
The process of adsorption occurs because the forces acting on the surface particles of a substance differ from those acting on the bulk of the substance. On the exposed surface, unlike inside the bulk, the particles are not surrounded by atoms on all sides.
Therefore, the forces on the interior are balanced, while those on the exterior are unbalanced. A surface’s residual forces that are out of balance tend to attract adsorbate particles. This leads to the adsorption process.
At a given temperature and pressure, the extent of adsorption increases proportionally to the surface area of the adsorbent.
Frequently Asked Questions – FAQs
Q.1 What is the difference between adsorption and absorption?
Adsorption substances adhere to the surface of a molecule, whereas absorption substances enter the liquid or solid’s bulk phase.
Q.2 What is an example of adsorption?
Adsorption is the deposition of molecular molecules onto a surface. Adsorbate refers to the molecular species adsorbed on a surface, whereas adsorbent refers to the surface where adsorption occurs. Clay, silica gel, colloids, and metals are typical examples of adsorbents.
Q.3 What are the different types of absorption?
The two forms of absorption processes are physical absorption and chemical absorption, depending on whether there is a chemical reaction between the solute and the solvent.
Q.4 What is the absorption process?
Absorption is a chemical process involving the transfer of a substance in one state to another substance in a different state.
Q.5 What are the major types of absorption spectroscopy?
The most frequent types of waves recorded by absorption spectroscopy include infrared, atomic, visible, ultraviolet (UV), and x-ray waves. Each spectrophotometer employs identical processes.
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