Removal of ions from saline water using N, P co-doped 3D hierarchical carbon architectures via capacitive deionization

Abstract

In recent years, increasing attention has been paid to capacitive deionization (CDI) and significant developments have been made as a result of the high efficiency and relatively low cost of this technique. While carbon materials have been regarded as promising CDI electrodes, their high hydrophobicity and low accessible surface area hinder further enhancement of salt adsorption capacity. To overcome this issue, we prepared herein highly hydrophilic N, P co-doped 3D hierarchical carbon architectures derived from graphene oxide, gallic acid, phytic acid (P source), and chitosan (N source) by an ingenious technique. Highly efficient removal of ions from saline water using N, P co-doped 3D hierarchical carbon architectures via capacitive deionization has been demonstrated for the first time. The N, P co-doped 3D hierarchical carbon architectures delivered very high specific adsorption capacities (up to 26.8 mg g⁻¹ at 1.2 V). The electrochemical performance remained nearly unchanged after 10 000 consecutive galvanostatic charge–discharge cycles, revealing good deionization stability and reusability. We believe that this work is of great significance to expand the access to freshwater resources in water-scarce regions.