China’s new hydrogel extracts seawater uranium

September 07, 2026

Chinese researchers have developed an advanced hydrogel capable of capturing uranium from highly concentrated seawater, potentially opening a new route to securing fuel for the growing global nuclear energy industry.

The material addresses one of the biggest obstacles facing uranium recovery from the ocean: extracting extremely small quantities of uranium while dealing with the enormous concentration of other dissolved salts.

Developed by researchers led by scientists at Hainan University, the new composite hydrogel performs particularly well in concentrated seawater and brine produced by processes such as desalination and salt production.

A vast uranium resource hidden in the ocean

Uranium is essential to most commercial nuclear power plants, but conventional supplies depend largely on mining terrestrial deposits.

The oceans represent an alternative resource. However, recovering uranium directly from seawater is technically difficult because uranium exists at extremely low concentrations and must be separated from many competing ions.

Concentrated seawater offers an interesting alternative.

Brine generated by desalination facilities and solar saltworks can contain substantially more uranium than ordinary seawater. According to the researchers, uranium concentrations in these environments can reach roughly two to 10 times those found in natural seawater.

Higher concentrations could make uranium recovery more practical, but concentrated brine creates another problem: extreme salinity can reduce the effectiveness of conventional uranium-absorbing materials.

New hydrogel behaves differently in salty water

The researchers tackled the problem by developing a composite material combining polyvinylphosphonic acid (PVPA) with polyamidoxime (PAO).

PAO-based materials are promising candidates for extracting uranium because their chemical groups can bind to uranyl ions. Unfortunately, conventional PAO hydrogels can shrink when exposed to highly saline environments.

That shrinkage makes some of their uranium-binding sites less accessible, reducing extraction performance.

The new PVPA–PAO hydrogel is designed to respond differently.

Instead of simply collapsing in concentrated salt solutions, interactions between ions in the surrounding water and charged groups within the material weaken some of the electrostatic attraction between its polymer chains.

This phenomenon, known as the anti-polyelectrolyte effect, allows the hydrogel structure to expand under high-salinity conditions.

The expanded network exposes more uranium-binding sites to the surrounding water, improving the material's ability to capture uranyl ions.

Hydrogel captures 43.89 mg of uranium per gram

Testing with concentrated natural seawater produced particularly promising results.

After being immersed for 24 days in concentrated seawater obtained from solar saltworks, the PVPA–PAO hydrogel achieved a uranium adsorption capacity of 43.89 milligrams per gram.

That corresponds to an average uranium uptake rate of approximately 1.83 mg per gram per day.

The researchers reported that previously studied PAO hydrogels achieved capacities of around 10 mg per gram under comparable concentrated-seawater conditions, highlighting the potential performance advantage of the new approach.

Material also resists biofouling

Efficiency is only one challenge facing materials deployed in real seawater.

Microorganisms can colonize surfaces over time, creating biofilms that interfere with adsorption and reduce long-term performance. Any practical uranium extraction technology therefore needs to withstand biological as well as chemical conditions.

The PVPA–PAO hydrogel demonstrated strong antibacterial properties, with the researchers reporting an antibacterial rate of 99.94%.

Its uranium adsorption performance in open concentrated seawater was also only 6.29% lower than in filtered seawater.

These findings suggest the material could remain functional even when exposed to microorganisms and other components found in real marine environments.

Hydrogel remains stable under extreme salinity

Mechanical durability presents another obstacle.

An adsorbent intended for practical uranium recovery must survive prolonged exposure to corrosive, highly saline water without losing its structure.

The researchers found that their hydrogel maintained its structural and mechanical integrity even under conditions reaching sodium chloride concentrations of up to 5 mol/L.

The material also demonstrated strong selectivity for uranium despite the presence of competing ions.

Together, these characteristics could make the hydrogel particularly interesting for industrial brines, where salinity levels may be considerably higher than those of ordinary seawater.

Desalination brine could become a valuable resource

The research has implications beyond uranium extraction alone.

Desalination plants generate concentrated brine as they produce freshwater. Salt-production facilities similarly create increasingly concentrated seawater during evaporation.

Instead of viewing these streams exclusively as waste or secondary products, they could potentially become sources of valuable materials.

A future integrated facility could theoretically produce freshwater or salt while simultaneously recovering uranium and possibly other useful elements from concentrated seawater.

Such an approach could improve resource efficiency while creating additional value from existing marine-processing infrastructure.

Could seawater become a new source of nuclear fuel?

Extracting uranium from the ocean has attracted scientific interest for decades, but laboratory performance does not automatically translate into commercially viable production.

Large-scale deployment would still require researchers and engineers to address manufacturing costs, regeneration and reuse of adsorbents, extraction infrastructure, long-term durability, environmental impacts and the economics of recovering uranium at industrial scale.

Nevertheless, the new hydrogel demonstrates an important material-design strategy.

Rather than treating extreme salinity solely as an obstacle, researchers have engineered a material whose structure becomes more favorable for uranium adsorption in a high-salt environment.

As nuclear power capacity expands and countries look for more diversified sources of nuclear fuel, technologies capable of recovering uranium from seawater and industrial brines could become increasingly important.

For now, the PVPA–PAO hydrogel remains a research-stage technology. But its combination of high uranium uptake, ion selectivity, mechanical strength and resistance to biofouling provides another step toward making the enormous quantities of uranium dissolved in the world's marine resources more accessible.