Difference Between Adsorption and Absorption

Edited By Team Careers360 | Updated on Jun 25, 2022 08:41 AM IST

What is absorption?

Absorption (absorption in Hindi is ‘avashoshan’) is a phenomenon (phenomenon Tamil meaning is ‘Nikaḻvu’) of assimilation (assimilation meaning in Tamil is ‘Oruṅkiṇaippu’) in which the constituent of a substance enters into bulk phase of another substance. In absorption, one substance is completely absorbed (absorb meaning in Tamil is ‘Uṟiñci’) in another substance. This is also a key difference between absorption and adsorption. Absorption may be of reactive nature or non-reactive nature. Chemical absorption is absorption of reactive nature.

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What is absorption?
What is adsorption?
What is desorption and what is sorption?
Distinguish between adsorption and absorption.

In Chemical absorption or reactive absorption, a chemical reaction takes place between the absorbed (adsorbed meaning in Marathi is ‘Gaḍhūna gēlēlā’) and the absorbing (absorbing meaning in Hindi is ‘avashoshit’) substances. Chemical absorption depends upon the concentration of its reactants and stoichiometry of the reaction.

Physical absorption is absorption of non-reactive nature. A physical absorption or non-reactive absorption depends on the absorbing (absorbing meaning in Hindi is ‘avashoshit’) substance and absorbed (adsorbed meaning in Marathi is ‘Gaḍhūna gēlēlā’) substance. It also depends on physical properties such as temperature, solubility and pressure. The substance which is getting absorbed is called absorbate and absorbent is substance absorbing the absorbent (absorbent meaning in Tamil is ‘Uṟiñcum’). Example: a sponge soaking water, liquid absorbed by solid, biological absorption of digested food by the wall of the intestine, etc.

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What is adsorption?

Adsorption (adsorption in Hindi is called ‘adhishoshan’ and adsorption in Tamil is ’Uṟiñcutal’) is the phenomenon in which adhesion of constituents of a substance takes place on surface of another substance. This is the most important characteristic to spot difference between absorption and adsorption. The substance getting adsorbed is called adsorbate (adsorbate meaning in Tamil is ‘parappirppi’) while the substance on which adsorbate is adsorbing is called adsorbent (adsorbent meaning in Tamil is ‘Uṟiñcum’). This is the key difference between adsorbent and adsorbate. Examples of adsorbent include alumina gel, zeolites, activated carbon, graphite, silica gel etc.

The process of adsorption takes place due to the condition that forces acting on the particles present on the surface of a substance are uneven. This is very distinct to forces acting on the bulk particles of the material. Unlike the particles inside the bulk, the particles present on the surface exposed to the environment are not surrounded by other constituents from all sides. The forces on the inside of the bulk phase balance each other whereas those on the exposed surface of the substance are unbalanced.

These unbalanced residual forces present on the surface attract the adsorbate particles by the process of adsorption. The difference between absorption and adsorption originates because of the fact that absorption is bulk phenomenon while adsorption is surface phenomenon. The greater is the surface area of adsorbent, higher is the extent of adsorption at a given temperature and pressure. Adsorption is dependent on temperature. Example: pollution mask, charcoal gas mask, etc. After understanding the definition of absorption and adsorption, we can now easily pinpoint the difference between absorption and adsorption.

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What is desorption and what is sorption?

Desorption (desorption meaning in Hindi is ‘vishoshan’) is the phenomenon in which the constituents of a substance detaches or removes itself from a surface or bulk matter. Sorption (sorption meaning in Hindi is ‘shoshan’) is the process of accumulation of constituents of one substance into another substance. The act of attachment in sorption and detachment in desorption highlights the main difference between desorption and sorption.(It is important to understand desorption and sorption to recognize the difference between absorption and adsorption. This is because all the processes are quite similar superficially but differ conceptually.)

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Distinguish between adsorption and absorption.

To differentiate between adsorption and absorption (‘avashoshan’ is the Hindi meaning of absorption) we need to first understand the difference between absorb and adsorb (meaning of adsorb in Hindi is ‘sokh lena’). Absorb meaning is to assimilate one substance into another while adsorb means to assimilate on a surface.

Difference between absorption and adsorption is given in the following table

Absorption	Adsorption
It is a phenomenon of assimilation in which the constituent of a substance enters into the bulk phase of another substance.	It is the phenomenon in which adhesion of constituents of a substance takes place on the surface of another substance.
It is a bulk phenomenon	It is surface phenomenon
The constituent of absorbate spread uniformly throughout the absorbent.	The constituents of adsorbate concentrate only on the surface of adsorbent.
It is endothermic process	It is exothermic process
It remains unaffected by temperature	It is a temperature dependent phenomenon.
The rate of reaction is uniform for absorption	The rate of reaction increases slowly and then achieves equilibrium.
Absorption examples include the absorption of liquid by a sponge.	Examples include adsorption of pollutants by pollution marks.

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Frequently Asked Questions (FAQs)

1. Write the absorption definition. Give an example for absorption.

Absorption (absorption Hindi meaning is ‘avashoshan’) is a phenomenon (phenomenon Tamil meaning is ‘Nikaḻvu’) of assimilation (assimilation meaning in Tamil is ‘Oruṅkiṇaippu’) in which the constituent of a substance enters into bulk phase of another substance. In absorption, one substance is completely absorbed (absorb meaning in Tamil is ‘Uṟiñci’) in another substance. Example: a sponge soaking water, liquid absorbed by solid etc.

2. Define absorb.

Absorb meaning is to assimilate one substance into another while adsorb means to assimilate on a surface.

3. Define desorption.

Desorption (desorption meaning in Hindi is ‘vishoshan’) is the phenomenon in which the constituents of a substance detaches or removes itself from a surface or bulk matter.

4. What is the difference between adsorption and absorption?

The difference between absorption and adsorption is:

Absorption	Adsorption
It is a phenomenon of assimilation in which the constituent of a substance enters into the bulk phase of another substance.	It is the phenomenon in which adhesion of constituents of a substance takes place on the surface of another substance.
It is a bulk phenomenon	It is surface phenomenon
The constituent of absorbate spread uniformly throughout the absorbent.	The constituents of adsorbate concentrate only on the surface of adsorbent.
It is endothermic process	It is exothermic process
It remains unaffected by temperature	It is a temperature dependent phenomenon.
The rate of reaction is uniform for absorption	The rate of reaction increases slowly and then achieves equilibrium.
Examples include absorption of liquid by a sponge.	Examples include adsorption of pollutants by pollution marks.