Capacitive deionization technology for ultrapure water production using porous carbon fiber electrodes
Capacitive deionization (CDI) system using porous carbon fiber electrodes to produce ultrapure water without membranes. Uses electric potential control for ion removal, avoiding membrane fouling challenges common in reverse osmosis. Bench-scale validation shows NaCl reduction from 1000 mg/L to ~200 mg/L and from 500 mg/L to below 10 mg/L, with higher ion transfer coefficient than regular carbon fiber or activated carbon electrodes. Targeted for small-scale ultrapure water applications.
Overview
Capacitive deionization (CDI) is an electrochemical water treatment technology that separates ions from water through electro-adsorption. This approach offers a promising alternative to reverse osmosis (RO) for small-scale ultrapure water production. By using electric potential rather than high pressure to drive ion removal, CDI is easier to manage and operate. Because no membrane is required, the technology avoids membrane fouling, a persistent challenge in conventional desalination systems.
The solution centers on porous carbon fiber electrodes developed in collaboration with Dr. Greg Liu at Virginia Tech. The combined expertise in advanced material synthesis and water treatment engineering supports practical deployment in ultrapure water generation.
Technical specifications
Core technology:
- Capacitive deionization using porous carbon fiber electrodes
- Electro-adsorption mechanism removes ions without membrane barriers
- Electric potential control replaces high-pressure operation
Validated performance:
- Mini CDI device reduces NaCl concentrations from 1000 mg/L to approximately 200 mg/L
- Reduces NaCl from 500 mg/L to below 10 mg/L
- Higher ion transfer coefficient compared to regular carbon fiber or activated carbon electrodes
Development pathway:
- Mass production methods for porous carbon fibers
- Scaled-up CDI system design meeting industrial ultrapure water requirements
- One-year validation timeline with Virginia Tech handling fiber synthesis and Washington University handling electrode conversion and system testing
Technology readiness level
The technology has completed preliminary validation with results submitted for publication in Science Advances and is currently in final acceptance stage. Performance has been demonstrated in a bench-scale mini CDI device. The next phase focuses on scaling from bench to practical system, including electrode manufacturing scale-up and pilot system design. Funding is sought for key personnel, materials, and testing to advance toward commercial readiness.
About Washington University in St. Louis
Washington University in St. Louis is a private research university with a large graduate and professional footprint and a major clinical enterprise. Its medical campus is integrated with a leading hospital system, enabling joint clinical research, secure data access, and large-scale trial recruitment. An adjacent innovation district and partner incubators provide flexible lab space, prototyping resources, and corporate co-location, while shared core facilities welcome external users under service agreements. Research is supported by NIH, NSF, DOE, and other competitive federal funding alongside industry sponsorship. A dedicated technology transfer office manages IP, licensing, startup formation, and streamlined sponsored research and clinical trial agreements.
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