Fig. 5. The single-ligand adsorption of 2-ketogluconate (kG) and the competitive binary-ligand (L) adsorption of kG and (a) PO₄, (b) AsO₄, (c) and SO₄ at equal total concentrations of 0.1 mmol L^–1 and 10 g kaolinite L^–1 as a function of pH and ionic strength. The solid lines represent the 1-pK basic Stern optimized fit to the experimental data. The dashed lines represent the model-predicted adsorption of kG in the binary systems using the surface complexation model developed for adsorption in the single-ligand gibbsite system.