surface excess isotherm

https://doi.org/10.1351/goldbook.S06178
The function relating, at constant temperature and pressure, Γi(n), Γi(l) or Γi(v), or the respective specific quantities nl Δxilm, As Γi(l)m or Vl Δcilm to the
mole fraction
(or concentration) of component i in the equilibrium liquid phase. With solutions of more than two components such isotherms are unequivocal functions only when the ratios of the
mole
fractions (or concentrations) of all other components except i are kept constant. (As is the
area of interface
, Γi(n), Γi(l), Γi(v) are relative adsorptions, Δxil is the change in
mole fraction
of i resulting from bringing a specified mass m of solid into contact with a specified amount of solution nl, Δcil is the change in concentration resulting from bringing a specified mass of solid into contact with a specified amount of solution of volume Vl.)
Source:
PAC, 1972, 31, 577. (Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry) on page 593 [Terms] [Paper]