Highly efficient extraction of uranium from seawater by natural marine crab carapace

The sustainable access to uranium resource is critical for the sustainable development of nuclear energy industry. The global seawater contains thousands of times more uranium reserves than that on the land and can be a promising supply of uranium. Nevertheless, extraction of uranium from seawater is challenging due to the complex seawater environment and it’s urgent to develop adsorbents that suitable for being used in seawater environment. Herein, inspired by the high uranium concentrations in natural marine animal carapaces, the grinded marine crab carapace is used for uranium extraction. The crystalline calcium carbonate in crab carapace is identified as functional components for uranium adsorption for the first time. The grinded crab carapace achieves a high uranium extraction capacity of 1.38 mg g−1 in natural seawater. The EXAFS analysis and DFT calculations reveal that uranyl ion from seawater is bound by forming coordination bonds between uranium atom and oxygen atoms from the carbonate group and between axial oxygen atom from uranyl ion with calcium atom. Considering the promising uranium binding ability in natural seawater, the marine crab carapaces are highly potential for being used in uranium extraction from seawater.