Including the bulk properties of a liquid, solid or gas is a phenomenon of absorption. It includes the molecules or atoms that pass through the surface and enter the volume of the material.
Physical absorption:
physiosorption o Physical adsorption is a type of adsorption that occurs upon contact with a solid or liquid surface for most particles.
chemical absorption:
Chemical absorption is a process of chemical reaction between absorbing substances and absorbed substances, it occurs when molecules or atoms are absorbed.
Here are some points of difference between physical and chemical absorption.
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physical absorption |
chemical absorption |
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It is a reversible absorption process. |
It is an irreversible absorption process. |
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Balance is easily achieved |
The balance is done gradually |
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Due to intermolecular van der Waal forces, physical absorption occurs |
Due to the formation of chemical bonds, chemical absorption occurs |
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Low heat of adsorption |
The heat of adsorption is very large |
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Decreases with increasing temperature |
Increases with increasing temperature |
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Increased pressure increases adsorption |
Pressure drop does not lead to desorption |
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It is easily adsorbed if the gases are easily liquefiable, it depends on the nature of the gas. |
Significantly specific and depends on the nature of the adsorbent and the adsorbate |
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Multimolecular layers form on the surface of the adsorbent. |
Unimolecular layers form on the surface of the adsorbent. |