Page 177 - Adsorbents fundamentals and applications

162 ZEOLITES AND MOLECULAR SIEVES

(C F ) N
4 9 3
10

9

(C H ) N
8 4 9 3
(C F ) NC F
2 5 2
3 7
7

Mordenite-LP 6 Neopentane
CCl
4
SF
6
5 Isobutane
CF 4
CF Cl 2 Propane
2
Cyclopropane
4 Xe
CO,CH 4
N , SO 2
2
O 2 Kr
Ar
Cl 2
3 H 2
H O
2
NH 3
Chabazite Erionite K Erionite Mordenite-SP 2
NaX CaX CaA NaA KA LiA

Zeolite pore size (A) s(A)
Figure 7.3. Correlation for molecular sieving of molecules (with kinetic diameter σ)invarious
zeolites with different effective pore sizes at temperatures of 77 K (solid lines) and 420 K (dotted
lines) (from Breck, 1974, with permission).

between effective pore sizes of selected zeolites and the kinetic diameters of
various molecules.
Separation and purification can also be accomplished by using differences in
diffusivities, that is, kinetic separation (discussed in Chapter 3). 4A zeolite has
been used in PSA separation for producing nitrogen for inert purge applications