Highly selective removal of U(VI) from aqueous solutions by porous nanomaterials

With the fast development of nuclear energy peaceful utilization, large amounts of U(VI) are not only required to be extracted from solutions for sustainable nuclear fuel supply but also inevitably released into the environment to result in pollution, which is hazardous to human health. Thereby, the selective extraction of U(VI) from aqueous solutions is crucial to U(VI) pollution treatment and also to nuclear industry sustainable development. In this minireview, we summarized the selective extraction of U(VI) from solutions by porous nanomaterials (i.e., porous carbon nanomaterials, covalent organic frameworks, metal organic frameworks, and other nanomaterials) using different techniques, that is, sorption, electrocatalysis, photocatalysis, and other strategies. The efficient high extraction ability is dependent on the properties of porous nanomaterials and the used techniques. The high surface areas, abundant active sites, and functional groups are efficient for the high sorption of U(VI), but the special functional groups such as amidoxime groups are more critical for high selective extraction. The electrocatalytic extraction is related to the active sites, especially the single atom sites, of the porous nanomaterials as electrode. The special functional groups, bandgap, electron transfer pathway and electron donor–acceptor structures of photocatalysts contribute the high photocatalytic extraction of U(VI). The interaction mechanisms are discussed from spectroscopic analysis and computational simulation at molecular level. In the end, the challenges and prospectives for the efficient extraction of U(VI) are described.