Abstract
The cation exchange equilibrium of the A[+]/B[2+] system (where A[+]= Na[+], H[+] and B[2+] = Mg[2+], Ca[2+], Sn[2+], Ba[2+]) has been studied. Attempts have been made to fit the experimental results with the statistical thermodynamic treatment to the uni-bivalent exchange system, but due to inevitable experimental errors and resin degradation this was unsuccessful. This theoretical approach, which has been developed in these laboratories, predicts that linear plots of Ln [mathematical equation] against [mathematical equation] should be obtained. After thorough analysis of the above treatment, some criticism of the theory has been made.