Fig. 6. Concentration of PO4 adsorbed on ferrihydrite (as calculated from XANES fitting analysis) plotted as a function of total adsorbed PO4 concentration in ferrihydrite-boehmite mixtures. (A) Linear regression fits for June 2002 and October 2002 data; (B) Comparison of June 2002 data with a no-preference line based on distribution of adsorbed PO4 between the minerals in direct proportion to their relative contributions to the maximum adsorption capacity of the mixed systems.