Difference between Adsorption and Absorption
|It is a surface phenomenon.||It concerns with the whole mass of the absorbent.|
|In it, the substance is only retained on the surface and does not go into the bulk or interior of the solid or liquid.||It implies that a substance is uniformly distributed, through the body of the solid or liquid.|
|In it the concentration of the adsorbed molecules is always greater at the free phase.||
In it the concentration is low.
|It is rapid in the beginning and slows down near the equilibrium.||It occurs at the uniform rate.|
Examples : (i) Water vapours adsorbed by silica gel.
(ii) NH3 is adsorbed by charcoal.
Examples : (i) Water vapours absorbed by anhydrous CaCl2
(ii) NH3 is absorbed in water forming NH4OH