# Adsorption Isotherms of Ethylene in NaX (Zeolite Structure FAU)

Adsorption Isotherms of Ethylene in NaX (Zeolite Structure FAU)

This Demonstration plots adsorbtion versus pressure, , at various temperatures for ethylene () in NaX, known as faujasite zeolite structure (FAU). The amount adsorbed, (expressed in mol/kg), increases at low temperatures and high pressures. The adsorption isotherm, shown in red, is given by the following relation:

P

C

2

H

4

n

P(n)=(m-n)expn++exp-

nm

K

0

C

1

C

2

2

n

C

3

3

n

(+n)

D

0

D

1

R

1

T

1

T

0

where is Henry's constant at , expressed in mol/(kg kPa), is the saturation capacity, equal to 2.9997 mol/kg, and , for =1 to 3, are the virial coefficients. If these coefficients are set equal to zero, one recovers the well-known Langmuir equation (the blue curve). The term is the differential enthalpy of adsorption.

K

0

T=

T

0

m

C

i

i

(+n)

D

0

D

1