Environmental science. Nano | 2021
3D-ordered honeycomb-like nitrogen-doped micro–mesoporous carbon for brackish water desalination using capacitive deionization
Abstract
Capacitive deionization (CDI) was currently one of the most popular methods in the field of desalination, which performance highly depended on the electrode materials. It was vital significance to design the structure of the electrode material reasonably to obtain high CDI salt adsorption capacity. In this work, an ordered porous structure was constructed in ZIF-8 by a novel method of sacrifice template to obtain the 3D ordered honeycomb-like nitrogen-doped micro-mesoporous carbon materials (3D HPC). The unique structure of double continuous wall and hole facilitated the penetration and transported of ions. It also improved the specific surface area utilization to provide active sites. Moreover, in-situ nitrogen-doped 3D HPC improved the electrosorption to salt ions through increased conductivity of 3D HPC. The electrochemical behavior of 3D HPC electrodes was analyzed through a series of electrochemical tests such as CV, GCD and EIS. The results showed that 3D HPC has the advantages of low internal resistance, high reversibility and good stability. Through batch electrosorption experiments, the desalination ability of 3D HPC in NaCl aqueous solution was evaluated. The 3D HPC-based CDI electrodes displayed the maximum salt adsorption capacity of 21.45 mg·g-1 in 500 mg·L-1 NaCl solution at 1.2 V. Outstanding desalination performance and cycle stability proved its bright prospects in the application of CDI.