ABSTRACT

The concept adsorption was introduced by Kayser in 1881 to outline the augment in the number of gas molecules over solid surfaces, a phenomenon formerly observed by Fontana and Scheele in 1777. In a thermodynamic sense, during physical adsorption of gases, the adsorbed phase is in equilibrium with the gas phase. Gas adsorption is normally considered as a physical adsorption process as the molecular forces implicated are van der Waals type interactions. The procedure to gather an adsorption isotherm using a volumetric facility is as follows: at first, gas from the container is introduced into the dose volume V1 of the previously evacuated vacuum equipment. The adsorptive or adsorbate is the gas or molecule dissolved in a liquid, which is adsorbed by the solid surface, that is to say, the adsorbent, whenever the gas or liquid is brought in contact with it.