A distribution isotherm which is not linear.
Note:
A non-linear isotherm can have several shapes, as classified by Brunauer et al. In @C01075@ convex or concave shapes are common, as well as combinations.
Source:
PAC, 1996, 68, 1591. 'Nomenclature for non-linear chromatography (IUPAC Recommendations 1996)' on page 1593 (https://doi.org/10.1351/pac199668081591)