Fig. 2. Variable Surface charge of three mineral soils from Sudbury (SUD 1), Rouyn-Noranda (RN 1), and Valleyfield (VAL 1) (: measured by the back-titration; solid line: predicted by the non-ideal competitive adsorption [NICA]–Donnan model).
: measured by the back-titration; solid line: predicted by the non-ideal competitive adsorption [NICA]–Donnan model).