Surface Engineered 2D-β-ketoenamine Covalent Organic Framework for Superior Dechlorination via Hybrid Capacitive...

Area of Science:

• Materials Science
• Electrochemistry
• Environmental Science

Background:

• Global water scarcity necessitates innovative desalination technologies.
• Hybrid capacitive deionization (HCDI) offers energy-efficient water desalination.
• Effective electrode materials are critical for HCDI performance, particularly for chloride ion removal.

Purpose of the Study:

• To develop a novel anode material for HCDI to enhance chloride ion removal.
• To investigate the performance and selectivity of a covalent organic framework (COF)-based anode in HCDI.
• To address the limitations in electrochemical desalination by focusing on anode material development.

Main Methods:

• Synthesis of a covalent organic framework (COF)-based redox-active anode material.
• Fabrication and testing of a hybrid capacitive deionization (HCDI) cell utilizing the COF anode.
• Evaluation of chloride ion removal capacity (Cl-RC), removal capacity rate (Cl-RCR), and selectivity using saline and real seawater samples.

Main Results:

• The COF anode achieved a chloride ion removal capacity of 71.5 mg g⁻¹ in 1300 ppm saline solution.
• A high chloride ion removal capacity rate of 1.85 mg g⁻¹ min⁻¹ was observed.
• The material demonstrated excellent stability (98.7% capacity retention over 30 cycles) and high selectivity for chloride ions in real seawater, with a Cl-RC of 89 mg g⁻¹.

Conclusions:

• The developed COF-based anode material shows significant promise for efficient and selective chloride ion removal in HCDI.
• This study represents the first use of a purposefully functionalized COF as an anode in HCDI.
• COFs hold potential for advancing capacitive deionization technologies to address global water desalination challenges.