Fig. 6. Kinetics of sorption of As(V), at pH 6.0 and 100% surface coverage, on gibbsite, noncrystalline Al hydroxide [Al(OH)_x], goethite, and ferrihydrite, using the Elovich model. The amount of As(V) added was 200 mmol kg^–1 for gibbsite, 300 mmol kg^–1 for Al(OH)_x, 200 mmol kg^–1 for goethite, and 600 mmol kg^–1 for ferrihydrite.