Activation and regeneration of adsorbent:

The term activation refers to those processes which are used to enhance the effectiveness of an adsorbent by improving the pore structure and increasing the surface area. In common, along with carbon, high temperature activation produces organophilic adsorbent or low temperature activation, a hydrophilic adsorbent. During adsorption, a pore of the adsorbent becomes filled along with adsorptive molecules. The word regeneration refers to the removal of the adsorbed molecules and the return of the adsorbent to its original state. The regeneration of the adsorbent can be carried out by gentle heating if the adsorbed molecules are volatile. They might sometimes be removed by elution or desorption with volatile solvent if they are non-volatile, which in turn, may be removed by gentle heating. With a few adsorbents overheating will destroy the pore structure e.g. silica gel, should not be heated above 200^oC. On the other hand, the rugged adsorbents, fuller's earth and bauxite, may be heated in an oxidizing atmosphere to temperatures sufficient to burn off the adsorbed material near 540^oC.