Final form of modified Langmuir adsorption isotherm     IV. Verification of modified Langmuir isotherm for experimental data

III. Discussion of modified Langmuir isotherm

The final form of the modified Langmuir adsorption isotherm ( Equation 9 ) under certain circumstances takes the same form as several well-known isotherms. Analysis of these circumstances as the relation between adjustable parameters is given below as Case 1 - Case 7.
 
Case 1
n=1 Langmuir isotherm
a1=aL=a (Ea=EL)

 
Case 2
n®¥ Henry isotherm
a1=aL=a (Ea=EL)

 
Case 3
n®¥ Hüttig isotherm
a1<aL (Ea>EL)

 
Case 4
n®¥ III type according IUPAC
a1>aL (Ea<EL)
Asymptote:

 
Case 5
n - finite value BET type of isotherm for 2 layers
a1<aL (Ea>EL)
Asymptote: p ®¥    V ® 2Vm

 
Case 6
n - finite value "sigmoid" isotherm

 
 

a1>aL (Ea<EL)

 For instance: n=4


 
Case 7
n - finite value
a1=aL= a (Ea=EL)
Final form of modified Langmuir adsorption isotherm     IV. Verification of modified Langmuir isotherm for experimental data