Adsorption is the capacity of a solid substance to attract to its surface molecules of a gas or solution with which it is in contact. Solid substances are called adsorbent and attracted surface molecules of a gas or solution are called adsorbate. Likewise surface tension, adsorption is an effect of surface energy. Absorption can be explained through isotherms, that is to say, functions relating the amount of adsorbate on the adsorbent, with its pressure (gas) or concentration (liquid). The first isotherm was designed by Freundlich and Küster (1894) for gaseous adsorbates:
x / m = kP1/n
where, x defines the adsorbed quantity, m defines the mass of the adsorbent, P defines the pressure of the adsorbate and k and n are the constant value for each adsorbent-adsorbate pair at a given temperature.
Adsorption can be divided into two sub-types, namely, (1) physical adsorption and (2) chemical adsorption. Physical adsorption is dependent on Van der Waals forces of attraction between molecules and it resembles with the condensation of liquids. Chemical adsorption, also known as chemisorption, requires activation energy as well as chemical forces for the specification of the chemicals involved.
x / m = kP1/n
where, x defines the adsorbed quantity, m defines the mass of the adsorbent, P defines the pressure of the adsorbate and k and n are the constant value for each adsorbent-adsorbate pair at a given temperature.
Adsorption can be divided into two sub-types, namely, (1) physical adsorption and (2) chemical adsorption. Physical adsorption is dependent on Van der Waals forces of attraction between molecules and it resembles with the condensation of liquids. Chemical adsorption, also known as chemisorption, requires activation energy as well as chemical forces for the specification of the chemicals involved.