Surface Engineered 2D‐β‐ketoenamine Covalent Organic Framework for Superior Dechlorination via Hybrid Capacitive Deionization
Najat Maher Aldaqqa, Sushil Kumar, José I. Martínez, Nada Elmerhi, Emad Alhseinat, Dinesh Shetty
Abstract
Abstract To prevent a global water shortage crisis, we must innovate to desalinate seawater. Hybrid capacitive deionization (HCDI), an energy‐efficient desalination method, depends on electrode materials. Removing chloride ions (Cl − ), a key salinity factor, is vital for balanced electrode capacity. Yet, efforts focus mainly on cathode materials for Na + capture, limiting the progress of electrochemical desalination. Herein, we have developed a covalent organic framework (COF)‐based redox‐active anode material with excellent chemical stability and unique pseudocapacitive behavior. In the HCDI cell, the rationally designed material showed a remarkable chloride ion removal capacity (Cl‐RC) of 71.5 mg g −1 in 1300 ppm saline solution with a noteworthy removal capacity rate (Cl − RCR) of 1.85 mg g −1 min −1 , while maintaining 98.7% capacity retention over 30 cycles. Under optimized conditions, the COF electrode displayed a high selectivity toward Cl − over other anions present in real‐seawater samples with Cl‐RC of 89 mg g −1 , implying its practical applicability. To the best of our knowledge, this work represents the first example of a purposefully functionalized COF serving as an anode in HCDI, highlighting the promising role of COFs in advancing capacitive deionization technologies.