Module 8 : Surface Chemistry
Lecture 36 : Adsorption
36.2

Adsorption Isotherms

36.2.6

BET Isotherm (contd..)

 

From equation (36.2.30) and 36.2.31), we have

  (36.2.32)
 
 
 

(36.2.33)
 
 

p* = equilibrium pressure, (ads) vapour putting

 

(36.2.34)
   
 
 
 
 

( 36.2.35)
 

can therefore be obtained from the slope of a plot of against z, and cVmono can be found from the intercept at z = 0, the result combined to give c and Vmono from the corresponding value of
Vmono at 273 K and 1 atm, number of molecules present in Vmono could be calculated. By knowing the contact area of a molecule, surface area of the adsorbent per unit mass could be determined.