Fig. 3. Adsorption isotherm on Na- and Ca-montmorillonite of: (a) desferrioxamine B (DFOB); (b) the ferric complex of DFOB (FOB). Symbols represent measured values, lines represent calculated values. Experimental conditions: two replicates; 5 g L^–1 clay minerals; pH 7.5; I = 0.01 M (KClO₄).