Adsorb vs. Absorb: What's the Difference?
Edited by Harlon Moss || By Janet White || Updated on October 3, 2023
Adsorb refers to the accumulation of molecules on a surface, while Absorb means to take in or soak up a substance uniformly.
Key Differences
Adsorb and Absorb, despite their phonetic similarity, depict two different processes in the realm of chemistry and physics. The word "Adsorb" refers to a process where molecules from a substance accumulate or adhere to the surface of another substance. This surface accumulation is generally a result of physical or chemical attractions. Absorb, on the other hand, describes the process in which one substance is taken into the body of another, leading to a uniform distribution or dissolution.
When a material adsorbs something, it effectively traps and binds the molecules at its surface. Consider activated charcoal; it can adsorb gases, meaning gases stick to its surface. This makes activated charcoal useful in applications like gas purification. In contrast, when a sponge takes in water, it doesn't merely allow water to stick to its surface; the sponge absorbs the water. The water is taken into the entirety of the sponge, filling its pores and spaces.
In some applications, it's crucial to ensure that substances are adsorbed rather than absorbed. For instance, in certain industrial processes, catalysts might adsorb reactants on their surface to expedite a chemical reaction. This is different from absorption, where a material would be wholly consumed or integrated. Absorption can be seen in our daily lives too; a paper towel absorbs a spill, taking the liquid into its fibers rather than just letting the liquid sit on its surface.
While both adsorption and absorption are about the interaction between substances, their mechanisms and outcomes are distinct. Adsorption often results in a thin layer of molecules on a surface, while absorption leads to a more uniform distribution or incorporation of one substance into another. These concepts, though scientific in nature, have broad applications in fields ranging from environmental science to manufacturing and medicine.
Comparison Chart
Definition
Accumulation of molecules on a surface
Taking in or soaking up uniformly
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Nature
Surface phenomenon
Bulk phenomenon
Result
Creates a thin layer on the surface
Leads to a uniform distribution
Mechanism
Physical or chemical attraction to a surface
Integration or dissolution into another substance
Examples
Activated charcoal adsorbing gases
Sponge absorbing water
Adsorb and Absorb Definitions
Adsorb
The process by which a solid holds gases or liquids on its surface.
Silica gel can adsorb moisture from the air.
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Absorb
To take in or soak up a substance.
The cloth can absorb a lot of water.
Adsorb
To gather molecules on a surface.
The metal plate can adsorb hydrogen.
Absorb
To assimilate or integrate materials.
The gel will absorb the liquid upon contact.
Adsorb
The adherence of atoms or molecules to a surface.
Certain materials can adsorb toxins efficiently.
Absorb
To consume or use up.
Plants absorb sunlight for photosynthesis.
Adsorb
To retain substances on an external layer.
The filter is designed to adsorb contaminants.
Absorb
To take (something) in through or as through pores or interstices.
Adsorb
Surface binding due to physical or chemical attractions.
The catalyst can adsorb specific reactants for the reaction.
Absorb
To occupy the attention, interest, or time of; engross
The problem completely absorbed her.
Adsorb
To take up by adsorption.
Absorb
To take up or occupy (one's time or interest, for example).
Adsorb
To accumulate on a surface, by adsorption
The gas was purified by adsorbing the impurities onto active carbon.
Absorb
To retain (radiation or sound, for example) wholly, without reflection or transmission.
Adsorb
To attract and bind (molecules of a substance in a fluid) so as to form a thin layer on the surface, by non-electrostatic forces; to bind by adsorption. Distinguished from absorb, in which the foreign substance penetrates the body of the absorbing material.
Absorb
To take in; assimilate
Immigrants who were absorbed into the social mainstream.
Adsorb
Accumulate (liquids or gases) on the surface
Absorb
To learn; acquire
"Matisse absorbed the lesson and added to it a new language of color" (Peter Plagen).
Absorb
To receive (an impulse) without echo or recoil
A fabric that absorbs sound.
A bumper that absorbs impact.
Absorb
To assume or pay for (a cost or costs).
Absorb
To endure; accommodate
Couldn't absorb the additional hardships.
Absorb
To use up; consume
The project has absorbed all of our department's resources.
Absorb
(transitive) To include so that it no longer has separate existence; to overwhelm; to cause to disappear as if by swallowing up; to incorporate; to assimilate; to take in and use up.
Absorb
To engulf, as in water; to swallow up.
Absorb
(transitive) To suck up; to drink in; to imbibe, like a sponge or as the lacteals of the body; to chemically take in.
Absorb
(intransitive) To be absorbed, or sucked in; to sink in.
The drops of water slowly absorbed into the dry sponge.
Absorb
To take in energy and convert it.
Heat, light, and electricity are absorbed in the substances into which they pass.
Absorb
In receiving a physical impact or vibration without recoil.
Absorb
In receiving sound energy without repercussion or echo.
Absorb
Taking in radiant energy and converting it to a different form of energy, like heat.
Absorb
(transitive) To engross or engage wholly; to occupy fully.
Absorb
(transitive) To occupy or consume time.
Absorb
(transitive) To assimilate mentally.
Absorb
To assume or pay for as part of a commercial transaction.
Absorb
(transitive) To defray the costs.
Absorb
(transitive) To accept or purchase in quantity.
Absorb
To swallow up; to engulf; to overwhelm; to cause to disappear as if by swallowing up; to use up; to include.
The large cities absorb the wealth and fashion.
Absorb
To suck up; to drink in; to imbibe; as a sponge or as the lacteals of the body.
Absorb
To engross or engage wholly; to occupy fully; as, absorbed in study or the pursuit of wealth.
Absorb
To take up by cohesive, chemical, or any molecular action, as when charcoal absorbs gases. So heat, light, and electricity are absorbed or taken up in the substances into which they pass.
That grave question which had begun to absorb the Christian mind - the marriage of the clergy.
Too long hath love engrossed Britannia's stage,And sunk to softness all our tragic rage.
Should not the sad occasion swallow upMy other cares?
And in destruction's riverEngulf and swallow those.
Absorb
Become imbued;
The liquids, light, and gases absorb
Absorb
Take up mentally;
He absorbed the knowledge or beliefs of his tribe
Absorb
Take up, as of debts or payments;
Absorb the costs for something
Absorb
Take in, also metaphorically;
The sponge absorbs water well
She drew strength from the minister's words
Absorb
Cause to become one with;
The sales tax is absorbed into the state income tax
Absorb
Suck or take up or in;
A black star absorbs all matter
Absorb
Engross (oneself) fully;
He immersed himself into his studies
Absorb
Assimilate or take in;
The immigrants were quickly absorbed into society
Absorb
Engage or engross wholly;
Her interest in butterflies absorbs her completely
Absorb
To engross or engage wholly.
The book was so interesting, it completely absorbed her attention.
Absorb
To accept or bear a cost or consequence.
The company decided to absorb the extra shipping fees.
FAQs
Does absorb imply a change in volume?
Not necessarily, but it does indicate a substance is taken in or soaked up.
Which happens faster, adsorption or absorption?
It varies based on the substances involved, but adsorption can often be more immediate at surfaces.
What happens when a material becomes saturated?
It can no longer absorb more of the substance.
Are Adsorb and Absorb interchangeable?
No, they refer to different processes; adsorb is surface accumulation, while absorb is about taking in.
What materials commonly absorb water?
Sponges, towels, and certain polymers can absorb water effectively.
Can gases be adsorbed?
Yes, certain materials can adsorb gases on their surface.
Why is adsorption used in filters?
Because it allows contaminants to stick or bind to the filter's surface.
Can liquids also be adsorbed?
Yes, liquids can be adsorbed onto solid surfaces.
Can adsorption be reversible?
Often, yes. Under certain conditions, molecules can be released from surfaces.
How do plants absorb nutrients?
Through their roots, plants absorb essential nutrients from the soil.
Can light be absorbed?
Yes, materials like pigments can absorb specific wavelengths of light.
Are adsorption and desorption opposites?
Yes, desorption is the removal of molecules from a surface, opposite of adsorption.
Is adsorption always a chemical bond?
No, it can be physical (physisorption) or chemical (chemisorption).
Why is adsorption temperature-dependent?
Because molecular interactions can change with temperature, affecting adsorption.
Why might a catalyst adsorb reactants?
To facilitate and speed up a chemical reaction.
How does absorption relate to digestion?
The digestive system breaks down food, and nutrients are then absorbed into the bloodstream.
Can both processes occur simultaneously?
Yes, a substance can adsorb onto a surface and then be absorbed into the material.
What's a practical example of absorption in daily life?
Using a paper towel to clean up a spill showcases absorption.
Can adsorption be used in detoxification?
Yes, certain materials can adsorb toxins, making them useful for detoxification.
What happens when a material can't absorb anymore?
It becomes saturated, and the excess substance remains unabsorbed.
About Author
Written by
Janet WhiteJanet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Harlon MossHarlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
