As countries expand long term clean energy plans, nuclear power remains a key source of stable, low carbon electricity. But there is a growing resource challenge. Easily mined uranium reserves are tightening, and exploration costs keep rising. That pressure has renewed interest in extracting uranium directly from seawater. Earth’s oceans hold nearly 4.5 billion tons of it, but at extremely low concentrations that have made efficient extraction almost impossible.
A new study may finally change that. Researchers Dr. Xishi Tai of Weifang University and Dr. Zhenli Sun of North China Electric Power University have developed a new class of sulfonic covalent organic frameworks, or S COFs, that dramatically outperform previous approaches, as reported by EurekaAlert.
The breakthrough came from a design concept they call stacking mode engineering. Instead of focusing only on chemical properties, the team looked at the geometry of how the internal layers sit relative to one another. They created an AB stacking arrangement that forms a confined pocket perfectly shaped for uranium ions. This allows four point coordination that locks the ions in place far more effectively than the traditional AA stacking mode.
The performance jump is striking. The AB stacked material showed a binding affinity about 1,000 times higher than the AA version. When the team tested the material in natural seawater, it extracted 31.5 milligrams of uranium per gram of sorbent in just 24 hours. No previous system has reached that level. The material also showed strong selectivity, ignoring ions like vanadium that normally interfere with uranium capture.
Researchers say this precision may help guide new ways of isolating valuable ions in complex environments. But real world deployment still faces challenges. Any extraction material must withstand rough ocean conditions, resist biological growth, and be regenerated repeatedly without degrading. It also has to scale up at a cost that can compete with mining.
Still, the team believes they have taken a meaningful step toward practical seawater uranium extraction. They expect continued improvements as smart materials and structural engineering techniques evolve.
The study appears in the journal Sustainable Carbon Materials.