Uranium is central to nuclear energy production, but terrestrial reserves are limited compared with the approximately 4.5 billion tons dissolved in the oceans. Uranium-bearing nuclear wastewater also requires effective treatment to prevent resource loss and environmental contamination. Capacitive deionization offers a promising solution because a low voltage drives charged ions toward porous electrodes, where they can be concentrated and later released. However, conventional carbon-based electrodes often require complicated high-temperature preparation and lack uranium-specific binding sites. Conductive-polymer electrodes are easier to prepare, but their relatively simple structures, restricted surface areas, and insufficient selectivity have limited their uranium-removal performance.
A study (DOI: 10.48130/scm-0026-0011) published in Sustainable Carbon Materials on 11 March 2026 by Jiaxing Li's team, University of Science and Technology of China, reports that combining electrical double-layer attraction with functional-group coordination enables rapid, high-capacity, and selective uranium recovery.
The researchers first synthesized phytic acid-doped polyaniline through heterogeneous solution polymerization and then immobilized chitosan on its spherical framework. Polyaniline provided a conductive backbone, while phosphate, hydroxyl, and amino groups supplied uranium-binding sites. Microscopy and spectroscopic analyses confirmed the material’s spherical, porous structure and successful incorporation of phytic acid and chitosan. The electrode contained both micropores and mesopores, had an average pore diameter of 45.2 nm, and absorbed a water droplet completely within approximately 1.15 seconds, demonstrating excellent wettability for rapid ion transport. Electrochemical testing measured an ionic conductivity of 189.04 S cm⁻¹. The team spray-coated the composite onto titanium sheets and tested it as the cathode in a flow-through capacitive deionization system. They varied phytic acid content, chitosan loading, solution pH, applied voltage, contact time, and initial uranium concentration. Performance peaked at approximately 29% chitosan loading and pH 5. Increasing the voltage from 0 to 1.2 V raised uranium uptake from 599.4 to 942.4 mg g⁻¹, with electrosorption reaching equilibrium within about 12 hours. Langmuir modelling predicted a maximum capacity of 973.1 mg g⁻¹, close to the experimental value of 954.1 mg g⁻¹ at high uranium concentration. Selectivity tests showed that the electrode preferentially captured uranium over competing ions in simulated seawater. In natural seawater, it removed 85% of the uranium within 10 days, lowering its concentration from 2.4 to 0.4 μg L⁻¹. It also captured substantially more uranium than nickel, cobalt, gadolinium, praseodymium, cerium, or lanthanum in simulated nuclear wastewater. After five regeneration cycles, removal efficiency remained 78%. X-ray photoelectron spectroscopy and density functional theory calculations indicated that uranium uptake resulted from the combined action of electrical double-layer storage and coordination with phosphate, hydroxyl, and amino groups; the calculated adsorption energy was −22.40 eV.
Overall, the study demonstrates that integrating a conductive polymer with naturally derived chitosan and phytic acid can overcome several limitations of existing uranium-capture electrodes. Its high uptake, low energy consumption, resistance to competing ions, and partial reusability make CS/PA-PANI a promising candidate for extracting uranium from seawater and recovering it from nuclear wastewater. Further work should focus on improving long-term cycling stability, preventing the loss of functional components during regeneration, and validating performance in larger continuous-treatment systems.
###
References
DOI
10.48130/scm-0026-0011
Original Source URL
https://doi.org/10.48130/scm-0026-0011
Funding information
This paper was sponsored by the National Natural Science Foundation of China (22276195).
About Sustainable Carbon Materials
Sustainable Carbon Materials (e-ISSN 3070-3557) is a multidisciplinary platform for communicating advances in fundamental and applied research on carbon-based materials. It is dedicated to serving as an innovative, efficient and professional platform for researchers in the field of carbon materials around the world to deliver findings from this rapidly expanding field of science. It is a peer-reviewed, open-access journal that publishes review, original research, invited review, rapid report, perspective, commentary and correspondence papers.