The influences of separators on capacitive deionization systems in the cycle of adsorption and desorption

Abstract

This research focused on the influence of different separator compartments on the performance of capacitive deionization (CDI) cells in terms of brackish water treatment. For comparison, different separators including filter paper(FP), carbon nanotube (CNT), and stainless steel fiber (SSF) on deionization and desorption rate of salt were examined. The best performance was obtained when the CNT separator was packed, followed by SSF and FP. Reducing the cell voltage from 1.2 to 0.4 V decreased the salt removal and electrode regeneration rate of SSF-CDI. Electrochemical impedance spectrometry (EIS) analysis revealed that the resistance and specific capacitance of separator materials are essential to the desalination and desorption performance of CDI. The electric double layers (EDLs) accelerated the ion transfer in the flow chamber due to storing excess ions, therefore increasing the desalination and electrode regeneration rate.