Ion Activity Coefficients in Ion Exchange Polymers: Applicability of Manning鈥檚 Counterion Condensation Theory

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• 作者：Jovan Kamcev ; Donald R. Paul ; Benny D. Freeman
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：November 10, 2015
• 年：2015
• 卷：48
• 期：21
• 页码：8011-8024
• 全文大小：670K
• ISSN：1520-5835

文摘

Manning鈥檚 counterion condensation theory, originally developed for polyelectrolyte solutions, was used to predict ion activity coefficients in charged (i.e., ion exchange) membranes with no adjustable parameters. Equilibrium sodium and chloride ion concentrations in negatively and positively charged membranes were determined experimentally as a function of external NaCl concentration, and ion activity coefficients in the membranes were obtained via a thermodynamic treatment. Theoretical values for membrane ion activity coefficients obtained via Manning鈥檚 model were compared with those obtained experimentally. Good agreement was observed between the experimental and theoretical values for membrane ion activity coefficients, especially at higher external NaCl concentrations. However, some deviation between experimental and theoretical values was observed in the dilute regime. Manning鈥檚 model was also used to obtain activity coefficients for various electrolytes in ion exchange resins using ion sorption data from the literature, and these values were compared to those obtained experimentally.