Multicomponent Ion Exchange Equilibria II. Ca2+-Mg2+-H+ on Amberlite IR 120

Department of Pure Chemistry, University Colleges of Science, Calcutta-700 009 Binary and ternary ion exchange equilibria involving Ca2+, Mg2+ and H+ ions have been studied by the batch technique, using the strong acid cation exchanger Amberlite IR 120. The ideal solid solution model of Argersinger et al has been used in the calculations of the thermodynamic equilibrium constants of the binary exchange equilibria ; the specific ionic interactions in the solution phase insofar as these affect the corresponding ionic activities have been taken into account in the calculations. The mutual agreement of the ∆G° values of the three exchange reactions which together constitute a "triangle" has been discussed. For the ternary exchange system the possibility of predicting ternary data by using the pair of binary exchange results containing the most preferred ion was examined. The graphical procedure suggested by Streat has been used, and the correlation between the experimental and the theoretically predicted results has been found to be good