Adsorption isotherms for m-cresol, quinoline, and 1-naphthol onto silica gel in n-hexane at 30℃ were measured in the concentration range of 1-30 mole/m³. The experimental results for m-cresol and quinoline were well represented by the generalized Toth isotherm, and for 1-naphthol by the superimposed two sites Langmuir model. At low concentrations the adsorbed amounts onto silica gel were decreased in sequence of quinoline, 1-naphthol, and m-cresol. However as the concentration increased, the sequence was reversed.
For binary systems, the competitive adsorption was quantitatively studied by introducing the competitive adsorption coefficient. The relative affinity of quinoline with respect to silica surface was larger than those of the other two components.