Influence of carbon electrode thickness and spacing on capacitive deionization performance

Abstract

Capacitive deionization (CDI) is a promising desalination technology capable of desalinating various water sources. It has attracted wide attention in the past few decades. In this study, effects of carbon electrode and spacer thicknesses on textural, electrochemical, and electrosorption characteristics of CDI were systematically evaluated. Specifically, CDI performance in terms of salt removal efficiency (R), salt adsorption capacity (SAC), and salt adsorption rate (ASAR) was discussed. The results showed that thick carbon layer electrode significantly improved the salt removal efficiency due to the high active sites for adsorption. In terms of ion removal per mass of the electrode, a reduction in salt adsorption capacity was investigated. In contrast, the thin electrode offered a fast electrosorption rate. A narrow spacing distance between a pair of electrodes exhibited a good electrosorption performance owing to relatively short ion diffusion distance and strong electric field strength. The present study demonstrates that a proper selection of the carbon electrode thicknesses and spacing for CDI cell assembly is critical to achieve a great electrosorption performance.