Hiroshi Utsugi

A three-parameter adsorption equation for extended type I isotherms

A three-parameter adsorption equation nθ=NB=c1x(1+c2x)+c2x1+c1x n n nwas derived on the basis where the monolayer is a localized adsorption and the molecules in an adphase over the monolayer behave like a compressed gas in a different potential from that of the gas phase. This equation tends to the Huttig-type adsorption equation when c2 = 1.0. This equation shows a good fit for the experimental isotherms classified as extended type I over nearly the whole range of relative pressures.

Reconsideration on the Hüttig adsorption equation including statistical-thermodynamical derivation

The Huttig-type adsorption equation has been derived statistical-thermodynamically on the basis of a different interpretation for higher layers over the monolayer in Huttigs original model. The differences of an adphase structure for higher layers between BET and the Huttig or Huttig-type equations and their adaptability to experimental isotherms are described.