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Updated: Aug 9, 2026
07:55
Ion-Exchange Membranes for the Fabrication of Reverse Electrodialysis Device
Published on: July 20, 2021
Scalable hybrid electrode-based capacitive deionization modules for practical water softening
Sang Baek Kim1, Gun Jang2, Wonji Jung3
1Department of Future Energy Engineering, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 16419, Republic of Korea.
Water Research
|August 7, 2026
Summary
New vanadium-oxide hybrid electrodes enable scalable capacitive deionization (CDI) for efficient water softening. This sustainable technology significantly removes hardness ions from tap water with high stability and performance.
Area of Science:
- Materials Science
- Electrochemistry
- Environmental Engineering
Background:
- Conventional water softening methods are energy-intensive and chemically reliant.
- Existing capacitive deionization (CDI) technologies face challenges in effectively removing hardness ions from domestic water.
Purpose of the Study:
- To develop scalable vanadium-oxide-based hybrid (VH) electrodes for practical water softening using CDI.
- To construct and optimize bipolar multistack CDI modules for efficient hardness ion removal.
Main Methods:
- Roll-to-roll fabrication of VH electrodes combining faradaic and capacitive mechanisms.
- COMSOL simulations for optimizing bipolar multistack CDI module design.
- Testing module performance with hard-water feed at various flow rates and cycling.
Main Results:
- VH electrodes demonstrated high divalent ion capacity, rate capability, and 300-cycle stability (93.2% retention).
- Optimized multistack CDI modules (105 stacks) achieved ion removal efficiencies of 89.9% at 0.5 L/min and 83.7% at 2.5 L/min.
- Demonstrated scalability and real-world applicability for sustainable hardness removal.
Conclusions:
- Redox-active hybrid materials show strong potential for practical CDI applications.
- The developed VH electrodes and CDI modules offer a viable strategy for sustainable water softening.
- This approach addresses limitations of conventional softening and existing CDI technologies.
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