Micromeritics ASAP 2460 - Freundlich Isotherm

Appendix C ASAP 2460 Operator’s Manual
C-10 246-42800-01 - Aug 2013
Quantity of the Monolayer (cm
3
/g STP):
Langmuir b Value:
Error of the Langmuir Surface Area (m
2
/g):
Freundlich Isotherm
The Freundlich isotherm has the form
where
C = temperature-dependent constant
m = temperature-dependent constant
P = equilibrated collected pressure measured by gauge at temp T
amb
Q = quantity of gas adsorbed
Q
m
= quantity of gas in a monolayer
The pressure is absolute; typically, m > 1. In terms of quantity adsorbed,
Taking the log of both sides yields
Q
m
1
S
---
=
bY
int
V
m
=
LAN
err
SA
Lan
S
err
S
-----------------------
=
Q
Q
m
--------
CP
1
m
----
=
QQ
m
CP
1
m
----
=
Qlog Q
m
C
1
m
----
Plog+log=