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Wednesday, December 24, 2014

What is desorption?

When a material is placed in Vacuum, the gas which was previously adsorbed begins to desorb i.e. to leave the material.

The desorption is influenced by

1.       Pressure
2.       Temperature
3.       Shape of material
4.       Kind of its surface

The pressure has a basic influence on the desorption phenomenon since according to its tendency of increasing over or decreasing below the equilibrium , the phenomenon of sorption or that of desorption appears.

The temperature has a clear influence on desorption phenomena. Desorption is endothermic, thus it is accelerated by increase of temperature.

The shape of the material influences desorption either if the gas is adsorbed or absorbed.

If the gas is adsorbed, then only the amount of surface is the influencing factor, but if the gas has to diffuse from the interior of the material to the surface, then the third dimension “thickness” is also influencing the rate of desorption.