DNA nano-pocket for ultra-selective uranyl extraction from seawater.

Extraction of uranium from seawater is critical for the sustainable development of nuclear energy. However, the currently available uranium adsorbents are hampered by co-existing metal ion interference. DNAzymes exhibit high selectivity to specific metal ions, yet there is no DNA-based adsorbent for extraction of soluble minerals from seawater. Herein, the uranyl-binding DNA strand from the DNAzyme is polymerized into DNA-based uranium extraction hydrogel (DNA-UEH) that exhibits a high uranium adsorption capacity of 6.06 mg g-1 with 18.95 times high selectivity for uranium against vanadium in natural seawater. The uranium is found to be bound by oxygen atoms from the phosphate groups and the carbonyl groups, which formed the specific nano-pocket that empowers DNA-UEH with high selectivity and high binding affinity. This study both provides an adsorbent for uranium extraction from seawater and broadens the application of DNA for being used in recovery of high-value soluble minerals from seawater.

Photoinduced Multiple Effects to Enhance Uranium Extraction from Natural Seawater by Black Phosphorus Nanosheets.

Based on the photoinduced photothermal, photoelectric, and photocatalytic effects of black phosphorus (BP) nanosheets, a BP-PAO fiber with enhanced uranium extraction capacity and high antibiofouling activity is fabricated by compositing BP nanosheets into polyacrylamidoxime (PAO). The photothermal effect increases the coordination interaction between UO2 2+ and the functional amidoxime group, and the photoelectric effect produces the surface positive electric field that exhibits electrostatic attraction to the negative [UO2 (CO3 )3 ]4- , which all increase the capacity for uranium adsorption. The photocatalytic effect endows the adsorbent with high antibiofouling activity by producing biotoxic reactive oxygen species. Owing to these three photoinduced effects, the photoinduced BP-PAO fiber shows a high uranium adsorption capacity of 11.76 mg g-1 , which is 1.50 times of the PAO fiber, in bacteria-containing natural seawater.

A Dual-Surface Amidoximated Halloysite Nanotube for High-Efficiency Economical Uranium Extraction from Seawater.

By chemical cross-linking the amidoxime group onto dual-surfaces of natural ore materials, namely halloysite nanotubes (HNTs), an efficient adsorbent, AO-HNTs, is developed. AO-HNTs show high uranium adsorption capacity of 456.24 mg g-1 in 32 ppm uranium-spiked simulated seawater. In natural seawater, AO-HNTs reach the high uranium extraction capacity of 9.01 mg g-1 after 30 days' field test. The dual-surface amidoximated hollow nanotubular AO-HNTs exhibit more coordination active sites for uranium adsorption, which is attributed to the high and fast uranium adsorption capacity. Because of the stable natural ore structure, AO-HNTs also show long service life. Benefiting from the low cost of HNTs, the cost for uranium extraction from seawater is close to the uranium price in the spot uranium market, suggesting that AO-HNTs could be used for economical extraction of uranium from the oceans.