Fig. 3. The adsorption of (a) PO₄, (b) AsO₄, and (c) SO₄ by gibbsite (G) and kaolinite (K) as a function of pH and ionic strength. The solid lines represent the 1-pK basic Stern optimized fit to the experimental data using the chemical models described in Tables 2, 3, and 4. The dashed lines represent the model-predicted ligand adsorption by kaolinite using the surface complexation model developed for gibbsite.