The following thesis is to be regarded as a
resume and brief extension of some of the Author's
work contained in the five accompanying papers.
These will be referred to as Paper I, II, -- V
as follows:-
• Paper I. On Adsorption from Solutions.
• II. On "Negative" Adsorption.
• III. The Adsorption of Vapours.
• IV. The Adsorption of Sulphur Dioxide
by Charcoal at - 10° C.
• V. Thermodynamics of Adsorption.PAPERS I AND II:
At the surface of separation of two phases
there is assumed to exist a transition layer where
the concentration of the constituents of the phases is
in general different from their concentrations in
bulk. We may, following Gibbs, consider this layer
as that included between two imaginary surfaces
selected one in each phase so that just outside the
properties found are those of the phase in bulk while .
inside the properties vary from those outside.If we sufficiently increase the interface and thus
the extent of the transition layer we may expect to
find a difference in the bulk concentration. This
is shown by selecting a substance which has already
a large specific surface and introducing it into a
gas or a solution. Thus, if charcoal is shaken up
with a solution of A in a solvent B a change in the
concentration of the solution is usually observed.
When the concentration of A decreases A is said to
be positively adsorbed by the charcoal, while if A's
concentration increases A is said to be negatively
adsorbed. A is positively adsorbed when the concentration
in the surface layer (relative to B) is
greater than its concentration in the solution.
Positive adsorption of A is negative adsorption of B
and vice versa
