Difference Between Adsorb and Absorb (With Table)

This is especially true for disciplines like physics and chemistry, where these two words cannot be used interchangeably even though they sound the same. In ordinary conversation, though, we aren’t concerned with the technicalities and refer to the process of soaking up or “absorbing,” which is the more popular and well-known of the two terms. However, there are considerable distinctions between the two, which is why we must be cautious when choosing which one to utilize.

Adsorb vs Absorb

The main difference between “adsorb” and “absorb” is that the latter is a bulk phenomenon in which the other molecules are absorbed throughout the body of the absorbent. At the same time, the former is a surface phenomenon in which the gas or liquid only attaches to the surface of the second substance.

To absorb is to go through the process of absorption, which is to say that the liquid or gas is absorbed into another fluid or solid body once it has been absorbed into the first. It is necessary to adsorb to go through the adsorption process, which occurs when any solid material clings to the surface of another solid material.

Adsorption is a distinct process. Instead of joining molecular bonds, one substance will congregate on another’s surface. The two materials’ atoms or molecules do not mix. Adsorption is the opposite of diffusion or dissolution. Adsorption is used in paint manufacturing. Paint must cling properly to the substrate it is intended to cover.

Comparison Table Between Adsorb and Absorb

Parameters of ComparisonAdsorbAbsorb
DefinitionA process in which molecules from a gas or liquid are absorbed into the solid or liquid medium’s bulk throughout its entirety.Assimilation of gaseous or liquid molecules occurs only on the surface of a liquid or solid media, not within the medium itself.
Type of PhenomenonThe phenomena of large groups.The phenomenon on the surface of the water.
Heat ExchangeThe process is exothermic.The process is exothermic.
Distribution of ConcentrationThe concentration of the absorbed substance is evenly distributed throughout the bulk of the material’s surface area.Only the surface of the adsorbent material has a higher substance concentration.
Affected byThe amount of substance in a given amount of space.The amount of surface area a substance has.
ExampleA series of steps accomplish gas purification.I am painting a surface, such as a wall, with a brush.

What is Absorb?

Absorb is the more prominent and well-known of the two words, and it is a verb that refers to the act of a liquid being absorbed by another substance, such as a sponge or a cloth. The material being absorbed is referred to as the absorbate, and the fabric keeping the absorbate is referred to as the absorbent. Consequently, it is an absorbent-volume-dependent process that persists consistently across time.

Physical adsorption and chemical absorption are the two basic types of absorption that can occur in the body. Chemical absorption occurs in two types: passive and active. There are no chemical reactions or bonds established between the absorbate and the absorbent in the passive type. Still, there is a vigorous chemical reaction in the active type and the production of chemical bonds.

Another phenomenon is known as absorption spectroscopy, which analyses the radiation based on its frequency and wavelength. It is also an essential procedure for determining the specific per cent of compounds present in the specimen under investigation. Examples of absorptions include purifying water by using alum, removing hardness from water, using aluminium, and using silica gel to dry up water after it has been treated.

What is Adsorb?

It is the process by which the adsorbate assimilates on the surface of the adsorbent, and as a result, it is a phenomenon that occurs on the surface. In this way, the absorbate concentration increases on the surface. The process is temperature-dependent, implying that the adsorption rate fluctuates with temperature and is not linear. Exothermic reactions are when heat is produced due to the response taking place.

In addition to physical and chemical absorption, the diverse types of adsorption include adsorption that requires less energy to complete and bonds established between the adsorbate and the adsorbent that require less energy to complete. It is also influenced by the surface area of the process and the temperature at which it occurs. Chemical forces induce chemical adsorption, and as a result, the bonds formed are strong, and the energy required for this is greater than that necessary for the physical equivalent. A further distinction is that physical adsorption is a multi-layered process, while chemical adsorption is a single-layered process.

Adsorption techniques such as the ion exchange process used in metallurgy for ore concentration, air purification, and other applications are examples of adsorption. Adsorption chromatography is a technique that allows us to separate pigments and hormones from one another.

Main Differences Between Absorb and Adsorb

  1. Absorption is a bulk phenomenon in which the material is assimilated throughout the entire body of a solid or liquid medium, as opposed to a surface phenomenon. Adsorption is a surface phenomenon in which a material attaches to the exterior surface of a second medium, which is called adsorption.
  2. The surface area of the medium determines how much material is absorbed, whereas the volume of a medium determines whether or not a substance is “absorbed.”
  3. Although both adsorption and absorption are endothermic processes, they are distinct.
  4. The concentration of the absorbed substance is uniform throughout the bulk of the material. Still, in the case of adsorption, the attention is uneven and concentrated mainly on the surface of the material.
  5. Absorption is frequently a chemical process, whereas adsorption is almost always a physical activity.

Conclusion

Consequently, the distinction between adsorbing and absorption can be summarised: one is a surface phenomenon, while the other is a bulk phenomenon. As a result, even if the differences between the two materials are not interchangeable, they are not visible to the naked sight since the interaction occurs between the atoms and molecules of the two materials.

References

  1. https://www.sciencedirect.com/science/article/pii/001346869500077R
  2. https://link.springer.com/article/10.1007/s00467-014-2968-3