Mechanism of Adsorption
The process of adsorption arises due to the fact that the forces acting on the surface particles of a substance are not same as that acting on the bulk of the material. Unlike the particles inside the bulk on the exposed surface, the particles are not surrounded by atoms on all sides. Consequently, the forces on the inside balance each other, whereas those on the surface are unbalanced. The unbalanced residual forces on the surface have the tendency to attract the adsorbate particles. This leads to the process of adsorption. It is to be noted here that at a given temperature and pressure, the greater the surface area of adsorbent, higher is the extent of adsorption. Adsorption is an exothermic process and enthaply change is always negative. When adsorbate