ASAP 2460 Operator’s Manual Appendix C
246-42800-01 - Aug 2013 C-11
Temkin Isotherm
The Temkin isotherm has the form
where
A =a
0
exp , where
0
and a
0
are adjustable constants
P = equilibrium pressure measured by gauge at temp T
amb
q
0
= the differential heat of adsorption at zero surface coverage
Q = quantity of gas adsorbed
Q
m
= quantity of gas in a monolayer
R = molar gas constant
T = bath temperature
In terms of quantity adsorbed
Thus, the plot of the natural log of absolute pressure vs. quantity adsorbed yields a straight line with
slope and intercept .
Q
Q
m
--------
RT
q
0
---------
A
0
Pln=
8.31441 10
3–
kJ
molK
--------------
Q
RTQ
S
q
0
--------------
A
0
P
P
0
------
ln+ln=
A
RTQ
m
q
0
a
---------------
ln