Development of a true multicomponent film diffusion controlled mixed-bed ion-exchange model and expanded to include radioactive isotopes.

摘要

Scope and method of study. The purpose of this study was to develop a generalized multicomponent mixed-bed ion exchange model that can handle an arbitrary number of species with any valence, especially multivalent dissociative species. Emphasis has been placed on a feasible and stable algorithm for solving the model. To achieve this goal, mass transfer equations and weak electrolytes dissociation equations in ion exchange column have been studied as well as column material balance equations; and based on which, two solving strategies are developed and compared. Finally, generalized solving strategy and algorithm for multicomponent MBIE model including several types of weak electrolyte constituents were implemented, and the effluent concentrations were determined by solving column material balance equations along with the flux expressions simultaneously. In addition, several radioactive isotopes species have been added to the model.; Findings and conclusions. A generalized multi-component MBIE model has been developed capable of handling an arbitrary number of species with any valence, especially multivalent dissociative species. New solving strategy is developed and been successfully programmed into a computer program; solving the flux expressions simultaneously leads to a more stable and less time-consuming result. The model satisfies the criteria established for validating proper model. Nuclear power plant water chemistry data indicate that the model is valid for UPW applications.