The Langmuir Treatment of Adsorption

Heat of adsorption Lov((KAi/ ,) High, order of heat of reaction 

Rate (activation energy) Very rapid, low E Nonactivated, low activated, high E 

The derivations may be carried out by using as a measure of the amount adsorbed either the fraction of the surface covered or the concentration of the gas adsorbed on the surfac Both procedures will be illustrated, although the second is the more useful for kinetic developments ((Chap. 9). The important assumptions are as follows  

All the surface of the catalyst has the same activity for adsorption i.e., it is energetically uniform. The concept of nonuniform surface with active centers can be employed if it is assumed that all the active centers have the same activity for adsorption and that the rest of the surface has none, or that an average activity can be used. 

There is no interaction between adsorbed molecules. This means that the amount adsorbed has no effect on the rate of adsorption per site. 

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