Materials for the Recovery of Uranium from Seawater

Abstract

More than 1000× uranium exists in the oceans than exists in terrestrial ores. With nuclear power generation expected to increase over the coming decades, access to this unconventional reserve is a matter of energy security. With origins in the mid-1950s, materials have been developed for the selective recovery of seawater uranium for more than six decades, with a renewed interest in particular since 2010. This review comprehensively surveys materials developed from 2000-2016 for recovery of seawater uranium, in particular including recent developments in inorganic materials; polymer adsorbents and related research pertaining to amidoxime; and nanostructured materials such as metal-organic frameworks, porous-organic polymers, and mesoporous carbons. Challenges of performing reliable and reproducible uranium adsorption studies are also discussed, as well as the standardization of parameters necessary to ensure valid comparisons between different adsorbents.

Significantly Enhanced Uranium Extraction from Seawater with Mass Produced Fully Amidoximated Nanofiber Adsorbent

“…[3,[26][27][28][29][30] Radiation-induced graft polymerization (RIGP) and atom-transfer radical polymerization (ATRP) strategies were commonly used to graft acrylonitrile monomer to some robust backbone polymer fibers, typically polyethylene (PE) fibers, to form polyacrylonitrile (PAN) grafted fabric, followed with the postamidoximation to convert nitrile groups to amidoxime groups. [3,[26][27][28][29][30] Radiation-induced graft polymerization (RIGP) and atom-transfer radical polymerization (ATRP) strategies were commonly used to graft acrylonitrile monomer to some robust backbone polymer fibers, typically polyethylene (PE) fibers, to form polyacrylonitrile (PAN) grafted fabric, followed with the postamidoximation to convert nitrile groups to amidoxime groups.…”

“…[3,[26][27][28][29][30] Radiation-induced graft polymerization (RIGP) and atom-transfer radical polymerization (ATRP) strategies were commonly used to graft acrylonitrile monomer to some robust backbone polymer fibers, typically polyethylene (PE) fibers, to form polyacrylonitrile (PAN) grafted fabric, followed with the postamidoximation to convert nitrile groups to amidoxime groups. [3,23,32] However, all of the fiber adsorbents obtained from these two methods require to process a postamidoximation treatment. [3,23,32] However, all of the fiber adsorbents obtained from these two methods require to process a postamidoximation treatment.…”

“…[3,32] Furthermore, up to 98.5% of the adsorbed uranium could be released from uranium-loaded PIDO NF adsorbents after elution, and the PIDO NFs could be regenerated and reused for more than eight cycles of uranium adsorption-elution. Third, and most importantly, after mild alkaline conditioning treatment, the PIDO NFs show excellent performance for uranium extraction even from a natural seawater environment with an adsorption capacity of 951 mg-U per g-Ads in 8 ppm uranium spiked seawater, and 8.7 mg-U per g-Ads after 56 d of exposure in nonspiked natural seawater.…”

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electricity on a large scale with ultralow greenhouse gases emission. [3] The oceans hold ≈4.5 billion tons of uranium, [4] making them a potential huge resource to support nuclear power production for hundreds of years. In order for nuclear power to be a sustainable energy generation in the future, economically viable sources of uranium beyond terrestrial ores must be developed.

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“…[5] All that is required is the ability to capture this element from seawater in cost-and energy-efficient ways. [3,17] In the 1990s, Japan Atomic Energy Agency (JAEA) research teams had successfully captured over 1083 g of uranium directly from ocean by using nonwoven fabric adsorbent, firmly establishing the practicality of uranium recovery from the oceans in appreciable quantities. [10][11][12][13][14][15][16] Among these technologies, the adsorption approach, particularly by using fiber-based adsorbents, is recognized as the most feasible process in terms of practicality, processability, cost, and environmental concerns.…”