Adsorption

The surface of a solid attracts and retains molecules of a gas or a dissolved substance which comes in its contact. These molecules remain only at the surface and do not go deeper into the bulk.

The phenomenon of attracting and retaining the molecules of a gas or a dissolved substance by the surface of a solid, resulting in their higher concentration on the surface is called adsorption.

The substance which gets adsorbed is called the adsorbate and the solid substance which adsorbs is called the adsorbent.

Adsorption and Absorption

The phenomenon of adsorption is different from that of absorption. The latter term implies that a substance is uniformly distributed throughout the body of a solid.