Page 3 3. Molecules are attracted to the surface of the adsorbent by van der Waals forces. Because the adsorbancy of a bed is finite, the adsorption-desorption cycle is necessarily a batch process.
Adsorption is exothermic and increases at lower temperatures.
In an environment such as the atmosphere of Mars, it can be assumed that all of the adsorbate is removed from the flow. This means that the rate of loading of the adsorbent bed is the same as the adsorbate mass flow. This relation holds until the bed approaches saturation. At saturation, the flow reaches a breakthrough point, where the adsorption rate quickly diminishes to zero. Pressure swing regeneration involves reducing the total pressure to drive off the adsorbate.