Predicting Carbonate Ion Transport in Alkaline Anion Exchange Materials

Abstract

Abstract : A detailed knowledge of how the ions transport through the membrane is needed in order to understand how it affects the ionic conductivity and stability of anion exchange membranes. Predictive tools have been created for hydroxide ions transporting through the membrane, however models are needed for predicting carbonate ion transport. Building on this knowledge from hydroxide ion transport, models will be developed to predict carbonate ion transport by using theory as well as experiments. A theoretical approach based on the dusty fluid model (DFM) will be developed to describe the carbonate ion transport. The DFM has been successfully used to predict transport in anion exchange membranes where it can describe hydroxide ion transport. Using this theory, the effects of carbonate ions in the AEM can be studied based on how ions transport through the membrane. Theoretical results were validated using experimental facilities constructed at the University of Connecticut (Storrs, CT) and the Army Research Laboratory (Adelphi, MD) to measure ionic conductivity and carbonate ion flux of the membrane. By exposing one side of a membrane to carbon dioxide, the carbonate flux was measured as well as the ionic conductivity of the membrane. The results were compared with the theoretical solutions for validation.