Influence of divalent cations adsorption on the performance of electromembrane process

Abstract

In this study, the adsorption equilibrium and kinetics of divalent cations were studied to describe transport phenomena occurring in an electromembrane process. The adsorption isotherms of divalent cations over cation-exchange resins were fitted to the Langmuir and Freundlich isotherms. Adsorption equilibrium experiments of divalent cations showed the preferential adsorption between adsorbent and adsorbate and Ca²⁺ showed about five times higher adsorption capacity than Mg²⁺. Adsorption kinetics was studied using the reversible first-order model and the forward and reverse reaction rate constants were estimated for divalent cations adsorption. The forward reaction rate constants for the removal of divalent cations were much higher than the reverse reaction rate constants, indicating that the rate of adsorption was dominant in ion-exchange process. In this study, the higher removal efficiency of Ca²⁺ than Mg²⁺ in an electromembrane process could be understood by the adsorption equilibrium and kinetic study.

Keywords:

• Adsorption
• Divalent cations
• Electromembrane process
• Ion exchange

Notes

Presented at 2013 International Environmental Engineering Conference and Annual Meeting of the Korean Society of Environmental Engineers (IEEC 2013) Seoul, Korea, June 11–13, 2013