Page 74 - Gas Adsorption Equilibria

60 Chapter 1

an unknown system parameter which is to be determined by a least square
optimization procedure of measured adsorption data; i. e. we propose

To realize this idea, one again has to introduce an analytic adsorption
isotherm, Eq. (1.30). Restricting to volumetric/manometric and gravimetric
measurements, i. e. observing that only reduced masses (1-31) can be
measured by these methods, the respective optimization function is

Here are measured data and are
optimization parameters. The number (N) of experimental data sets available
should exceed the square of the number of parameters to be determined, i. e.
Once the volume has been determined from
(1.38), the masses and can be calculated from Eq. (1.31) as

It also should be noted that within procedure (P3), (1.37) the density of the
sorbate phase

can be calculated from (1.32) with and (1.39) as

This quantity can provide information on phase changes within the sorbate
layer, for example the transition from a lattice gas type structure, cp. Fig. 1.2,
to a patch-liquid, or a dense mono-layer structure [1.3].

Another proposition for the volume of the combined sorbent/sorbate
phases is, to consider explicitly the mass dependent volume of the