Capacitive deionization (CDI) represents a novel technology for the desalination and purification of seawater. Selecting the appropriate electrode material is crucial, with carbon electrodes frequently employed owing to their high specific surface area, extensive porous structure, and environmentally sustainable nature. This study presents a nitrogen-doped porous carbon, derived from household waste, which demonstrates outstanding electrochemical and desalination performance. The purified chitosan was mixed with a specific ratio of CaCO3 and carbonized at 800 °C to produce chitosan porous carbon (CPC-T). To verify the role of the templating agent, its performance was compared with chitosan porous carbon (CPC) prepared by direct carbonization. CPC-T possesses more mesoporous structures (31.25%), shortening ion transport pathways and significantly enhancing charge transfer rates. The nitrogen-rich doping (8.65 at%) provides numerous active sites and excellent conductivity, making it highly appropriate for capacitive deionization applications. Compared to CPC prepared without a templating agent, CPC-T has a higher specific capacitance (101.5 F g−1 at a scan rate of 2 mV s−1) and good cycling stability. The CDI cell made from it exhibits a salt adsorption capacity (SAC) of 25.8 mg g−1 for 500 mg L−1 NaCl solution at an applied voltage of 1.4 V, retaining 88% capacity after 50 adsorption–desorption cycles, demonstrating excellent desalination regeneration performance. Additionally, among different concentrations of salt solutions, the CPC-T material shows the best desalination performance for the test solution at a concentration of 500 mg L−1. For different solute ions, the CDI cell with this material as the electrode exhibits excellent desalination performance for Ca2+, with a SAC value of up to 34.02 mg g−1. This is a self-doped porous carbon material that significantly outperforms traditional carbon-based materials. Graphical abstract Schematic representation of the transformation of diverse biomass resources into heteroatom-doped graphene derivatives through pyrolysis, hydrothermal carbonization, and chemical/physical activation processes. These advanced carbon materials exhibit enhanced properties for applications in electrochemical energy storage systems, including batteries, supercapacitors, and fuel cells.

Nitrogen-rich self-doping modified porous carbon material as a CDI electrode for brine desalination

期刊论文
发表日期：

2025年3月21日

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Bin Hui,
Houqi Zhou,
An Liu,
Chi Fei,
Ting Xu,
Chunyu Chen,
Dianchun Ju,
Han Ma,
Zuoqiao Zhu,
Rui Mao

摘要

Capacitive deionization (CDI) represents a novel technology for the desalination and purification of seawater. Selecting the appropriate electrode material is crucial, with carbon electrodes frequently employed owing to their high specific surface area, extensive porous structure, and environmentally sustainable nature. This study presents a nitrogen-doped porous carbon, derived from household waste, which demonstrates outstanding electrochemical and desalination performance. The purified chitosan was mixed with a specific ratio of CaCO₃ and carbonized at 800 °C to produce chitosan porous carbon (CPC-T). To verify the role of the templating agent, its performance was compared with chitosan porous carbon (CPC) prepared by direct carbonization. CPC-T possesses more mesoporous structures (31.25%), shortening ion transport pathways and significantly enhancing charge transfer rates. The nitrogen-rich doping (8.65 at%) provides numerous active sites and excellent conductivity, making it highly appropriate for capacitive deionization applications. Compared to CPC prepared without a templating agent, CPC-T has a higher specific capacitance (101.5 F g⁻¹ at a scan rate of 2 mV s⁻¹) and good cycling stability. The CDI cell made from it exhibits a salt adsorption capacity (SAC) of 25.8 mg g⁻¹ for 500 mg L⁻¹ NaCl solution at an applied voltage of 1.4 V, retaining 88% capacity after 50 adsorption–desorption cycles, demonstrating excellent desalination regeneration performance. Additionally, among different concentrations of salt solutions, the CPC-T material shows the best desalination performance for the test solution at a concentration of 500 mg L⁻¹. For different solute ions, the CDI cell with this material as the electrode exhibits excellent desalination performance for Ca²⁺, with a SAC value of up to 34.02 mg g⁻¹. This is a self-doped porous carbon material that significantly outperforms traditional carbon-based materials.

Graphical abstract

Schematic representation of the transformation of diverse biomass resources into heteroatom-doped graphene derivatives through pyrolysis, hydrothermal carbonization, and chemical/physical activation processes. These advanced carbon materials exhibit enhanced properties for applications in electrochemical energy storage systems, including batteries, supercapacitors, and fuel cells.