Specific surface excess amount, definition

The definition of the electrosorption valence involves the total surface excess, not only the amount that is specifically adsorbed. It is common to correct the surface excess F, for any amount that may be in the diffuse double layer in order to obtain the amount that is specifically adsorbed. This can be done by calculating the excess in the... 

It is important to note that in order to calculate the amount adsorbed n, the amount of liquid in the adsorbed phase, (n ), must be known. Since this quantity is not subject to a direct measurement it should be recognized that the amount adsorbed is not a unique variable and that it always should be related to a specific definition of the adsorbed phase or to a specific experimental technique used for separating the solid and the adsorbed phase from the bulk liquid phase. This point is quite obvious from Figure 1 as a shift in the dividing line between adsorbed and bulk phases would not change the value of the surface excess, but the amount adsorbed would be changed. 

In this chapter, the fundamental concepts of colloid science have been introduced. The definition of colloidal particles, those with sizes (in all directions) ranging from 1 nm to 10 pm, has been presented, and their relevance in soil science is stated. The importance of surface properties was remarked, introducing several definitions. The specific surface area is the area per unit mass the surface tension (or surface free energy) is defined as the Gibbs free energy per unit area. The surface excess of a given species is the amount (in moles per unit area) which is accumulated... 

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