Adsorption of argon on non-porous silica
Argon adsorption data at 87K on the reference silica (Lichrospher Si-1000)
reported in 10
were used for analysis of the 
Equation
9.
Figure 1 illustrates the behavior of the equation proposed
for various values of n. In the relative pressure range 0.005 - 0.6 the
best fit was obtained for n = 8. The surface area of silica calculated
for this relative pressure range from 42 experimental points was 18.2 m2/g.
It is in good agreement with value obtained in the previous work, 10
19.3 m2/g in the relative pressure interval 0.04 - 0.2 from
13 experimental points. It can be assumed that the equation proposed is
a useful tool for estimation the surface area of adsorbents. It is recommended
that about 20 data points should be taken for careful surface area work.
| Figure 1 |
Behaviour of the Proposed Isotherm Equation |
Figure 2 shows the comparison of above data fitting using Equation
9 and the other adsorption models (Hüttig, BET, and
Toth). It was found that the modified Langmuir isotherm in the pressure
range under investigation is sufficiently flexible to give a good representation
of data.
| Figure 2 |
Comparison of the Behaviour of the Various
Isotherm Equations |
