PHYSICAL CHEMISTRY IN BRIEF

CHAP. 13: PHYSICAL CHEMISTRY OF SURFACES [CONTENTS] 447

Obr.13.4:Adsorption isotherms

For an ideal mixtureci

(

∂lnγi[c]

∂ci

)

T

→0 we have

Γi, 1 =−

ci

RT

(

∂γ

∂ci

)

T

. (13.29)

This equation allows for determining the relative adsorption of a dissolved component in the
surface layer provided that we knowγ=γ(ci).

Example

Given that Szyszkowski’s equation (13.25) applies, derive relations forΓ 2 , 1 at low, medium and

high concentrations. Assume ideal behaviour of the solution.