Fig. 6. (A) Charge Distribution Multisite Surface Complexation (CD MUSIC) model predictions for oxyanion adsorption for the competitive adsorption of Si and As(III) on goethite. (B) CD MUSIC model predictions for zeta potential for the competitive adsorption of Si and As(III) on goethite. Model predictions are based on the equilibrium constants calculated from single ion adsorption of As(III) and Si. Symbols represent experimental data, lines represent CD-MUSIC model predictions. Suspension density = 1 g L^–1, background electrolyte 0.01 M NaNO₃.