Capacitive deionization employing pore-filled cation-exchange membranes for energy-efficient removal of multivalent cations

Abstract

Abstract In this work, novel pore-filled cation-exchange membranes (PFCEMs) have been successfully prepared and characterized for the application to a cost-effective and energy-efficient membrane capacitive deionization (MCDI) process. The PFCEMs are designed and fabricated to contain both sulfonic acid groups and weak acid chelating groups for the applications in a wide pH range as well as efficient removal of multivalent cations. The PFCEMs exhibit high selectivity coefficients for multivalent cations and excellent electrochemical properties superior to those of a commercial membrane. The MCDI processes employing the PFCEMs show excellent desalination performances, especially with high removal efficiency for multivalent cations and high energy recovery efficiency, superior to that of the cell utilizing a commercial membrane owing to the low mass transport resistance and high selectivity for multivalent cations.