Ion Exchange of H , Na , Mg2 , Ca2 , Mn2 , and Ba2 on Wood Pulp

Ion exchange selectivity coefficients were measured for the partition of metals between solution and pulp fibers. The method accurately models the ion exchange isotherms for all cation pairs evaluated and is accurate up to approximately 0.05 molar concentrations. Selectivity coefficients were determined for calcium and magnesium with each other and with hydrogen, sodium, manganese, and barium. Measurements made at 25°, 50°, and 65°C were used to determine the enthalpy and entropy of the reactions. The data follow the expected linear free-energy relationship. These results can be used to estimate the ion exchange selectivity coefficients for any temperature within the experimental range.