Kinetic parameters of isotopic exchange reaction in finite bath

A mathematical model has been proposed for an isotopic exchange reaction between the solid particles and ions in a solution of finite volume. A theoretical equation has been derived to predict the exchange fraction as a function of the dimensionless time T with the kinetic parameters ξ, ξ 1 and final fractional uptake U as parameters for the exchange rate controlled by combined film diffusion, surface chemical reaction and intraparticle diffusion. The exchange fraction increases as the values of T, U, ξ and ξ, increase. Experimental results of the isotopic exchange systems CaCO 3 (s)Ca 2+ (aq), CaC 2 O 4 (s)/ Ca 2+ (aq) and Ca‐form Dowex 50W‐X8/Ca 2+ (aq) agree well with the theoretical equation proposed in this study.