Researchers from the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS) have developed an innovative method for the pre-enrichment of uranium in seawater by membrane filtration.
Uranium is the vital source for the production of nuclear energy. There are about 4.5 billion tons of uranium in seawater, 1,000 times more than land reserves. However, the extremely low concentration of uranium and the huge amounts of coexisting ions, especially K+N / A+California2+ and Mg2+, makes the extraction of uranium from seawater very difficult. Thus, it is of great importance to enrich uranium and reduce the difference in concentration between uranium and the main coexisting ions.
In a study published in chemical engineering journalIMP researchers report the development of an efficient method to pre-enrich uranium in seawater by membrane filtration, based on the large differences in diameter of hydrated ions between UO22+ and the main coexisting ions.
Researchers fabricated a new type of composite glycine cross-linked graphene oxide (GO-Gly) membrane with good ion sieving properties, which can meet the requirements of uranium pre-enrichment in water from mer. The cross-linking of GO by glycine not only overcomes the swelling defect of the GO membrane in solution, but also meets the size requirement of the separation channel of uranium from coexisting major ions. In addition, the membrane structure can remain stable when immersed in aqueous solution for a long time.
Researchers investigated the ion rejection and enrichment properties of uranium and major coexisting ions in single ion solutions and simulated seawater, respectively. They found that almost 100% of the uranium was rejected by the GO-Gly membrane. Moreover, only uranium was obviously enriched while the concentrations of the main coexisting ions remained almost constant by continuously filtering the simulated seawater with the membrane.
The results confirm that the GO-Gly membrane is a good candidate for the pre-enrichment of uranium in seawater. This new method combined with traditional methods is expected to significantly improve the efficiency of uranium recovery and promote the actual application of uranium resources in seawater.
This work was financially supported by the National Natural Science Foundation of China and the West Light Foundation of CAS.
Resources
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Jian Chu, Qinggang Huang, Yuhua Dong, Zeen Yao, Jieru Wang, Zhi Qin, Zhigang Ning, Jianjun Xie, Wei Tian, Huijun Yao, Jing Bai (2022) “Enrichment of uranium in seawater by the glycine-crosslinked graphene oxide membrane,”
chemical engineering journalVolume 444, doi: 10.1016/j.cej.2022.136602
