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.
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