Adsorbents are the materials or the substance on which any other substance adsorbed (adsorbate).
The activation of adsorbent is the process in which the adsorption power of the adsorbent is increased.
It can be increased by increasing the surface area of the adsorbent.
As the surface area of the adsorbent increases there will be more and more molecules adsorbed thereby increasing the adsorption. Therefore, by activation of the adsorbent adsorption increases.