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C. Wolfrum, K. Bunzl, Gerhard Dickel, Gerhard Ertl
Kinetics of Isotopic- and Ion Exchange in Ternary Mixtures of Cation Exchangers
Keywords: Ion exchange, Isotopic exchange, Kinetics
The kinetics of isotopic exchange Cs+ - Cs+ and ion exchange Cs+ - H+ in a mixture of three cation exchangers was investigated experimentally and theoretically in a concentration range, where film diffusion is the rate determining step. Simulating this ternary mixture by using three single ion exchanger beads stirred in 1 ml solution and labelling with Cs-134, made it possible to measure the kinetics of the ion exchange processes of each bead as well as in the solution phase independently.
Theoretical calculations showed that these rates can be described by a system of three differential equations, which are solved numerically with a computer. Depending on the initial conditions of the mixture the Cs-concentration in either one or two of the exchangers or in the solution can overshoot its eventual equilibrium value. If the rate coefficients ofindividual ion exchanger particles are measured in separate experiments, the kinetics of isotopic and ion exchange reactions in the mixture can be calculated without adjusting any parameter. The rates of all ion exchange reactions can be described by using the same rate coefficients, independent of the initial condition of the system (forward and reverse ion exchange processes).
Zeitschrift für Physikalische Chemie, Oldenbourg Wissenschaftsverlag
Print ISSN: 0942-9352
Volume: 135, 02/1983
Pages: 185 - 199