Potentiometric titration of poly(acrylic acid) in mixed counterion systems: Chemical binding of Cd ions Original Research Article

Potentiometric titration curves of various Cd/poly(acrylic acid) systems have been obtained in order to study the cadmium poly(acrylic acid) interaction. The experimental data, in terms of pKa versus α, is well described by taking into account chemical binding of the cadmium ions with the polymer and electrostatically bound potassium counterions as calculated by the counterion condensation approach. In this way, the speciation of both divalent and monovalent counterions in solution is readily calculated.