Basis of differentiation

Adsorption

Absorption

definition

Accumulation of substance at the surface; this process creates a film on the surface

Assimilation of substance throughout the solid or liquid; a fluid becomes dissolved by a liquid or a solid

Rate of reaction

It increases steadily until it reaches equilibrium

Remains at the same rate

Temperature

Efficient at low temperatures

Not affected by temperature

Heat exchange

Exothermic process

Endothermic process

Concentration

The amount of substance at the surface of the adsorbent material is not the same as its concentration within the bulk 

Remains the same throughout the substance