Physical adsorption, also known as physisorption, is a reversible phenomenon involving weak Van der Waals forces between adsorbate and adsorbent, whereas chemisorption is an irreversible phenomenon involving strong chemical interaction between adsorbate and adsorbent.
|1.||It is a reversible phenomenon.||It is an irreversible phenomenon.|
|2.||Physisorption is caused by Van der Waals forces.||It is caused by chemical bond formation.|
|3.||It is not specific in nature.||It is highly specific in nature.|
|4.||Low temperature favors the physisorption process. It decreases as the temperature rises.||High temperature is favorable for adsorption. It increases as the temperature rises.|
|5.||Easily liquefiable gases are readily adsorbed.||Gases that can react|
with the adsorbent show
|6.||Enthalpy of adsorption is low (20–|
40 kJ mol-1).
|The enthalpy of chemisorption is high (80-240 kJ mol-1).|
|7.||Physical adsorption has a lower activation energy.||Chemical adsorption has a higher activation energy.|
|8.||Physisorption is a weak phenomenon.||It is a strong process.|
|9.||It is a multi-layered process.||This type of adsorption is almost entirely a single-layered phenomenon.|
|10.||For example: Adsorption of oxygen or hydrogen on the surface of charcoal||For example: Adsorption of oxygen on metal surfaces.|
- Hiemenz P. C. & Rajagopalan R. (1997). Principles of colloid and surface chemistry (3rd ed. rev. and expanded Paul C. Hiemenz Raj Rajagopalan). Marcel Dekker.