Uranium from Seawater is Getting Cheaper than Mined Uranium | NextBigFuture.com

Researcher Jiang Biao of the Green Chemical Engineering Technology Research and Development Center of the Shanghai Advanced Institute of the Chinese Academy of Sciences and his team developed a nanofiber functional membrane, which successfully extracted kilogram-level uranium from seawater and reduced the cost from US$560 per kilogram It reaches US$150 per kilogram, which is very close to the land mining cost of US$130 per kilogram.

Jiang Biao’s team is working with the National Nuclear Corporation to improve the technology. Sea trials will be carried out in the later stage to extract tons of uranium, which is expected to control the cost of extracting uranium from the sea to about 100 US dollars per kilogram.

There is 4.5 billion tons of uranium in the oceans.

At a meeting of the China Seawater Uranium Extraction Technology Innovation Alliance Council, China’s planners proposed a three-step strategy for seawater uranium extraction in the next 30 years:

2026-2035 is the second stage. During this period, a ton-level demonstration project for extracting uranium from seawater should be built.

2036-2050 is the third stage. The continuous production of uranium products extracted from seawater.

Energy efficient extraction would require putting materials into the great ocean currents. The currents move the water through the materials where uranium would be extracted. Getting a thousand tons or so per year would require collection over about 1000 square kilometers.

In 2023,CNNC noted that only a few institutes in China have carried out on-site tests of seawater uranium extraction. It said its new marine test platform has the ability to carry out material verification and amplification experiments in real ocean conditions.

There are various published studies by China to extract urarium from seawater. Researchers used seawater from the Bohai Sea, off the east coast of China, to test their new cloth. The specially coated electrodes were able to extract 12.6 milligrams of uranium per gram of water over a 24-day period—a greater amount than was retrieved with other uranium-extracting methods examined in the study.

Furthermore, the new uranium ion extraction method produced results that were three times faster than natural accumulation of ions on the cloth.

Chemical Engineering Journal – SA-DNA hydrogel microspheres for Ultra-Selective uranyl (VI) extraction from seawater
Highlights

• An adsorbent with ultra-high selective adsorption for UO22+ was obtained by a facile and scalable method.
• Materials are readily accessible and cost-effective.
• Detailed analysis of the mechanism of selective UO22+ adsorption on adsorbents.
• The adsorbent exhibits favorable recyclability and recycling.
• Expanding the applicability of DNA and development of novel resource ion adsorbents.

Abstract
Extraction of uranium from seawater is vital for the advancement of nuclear energy. However, the synthesis of selective adsorbents remains challenging. In this study, affordable sodium alginate (SA) and functional DNA strands were selected to fabricate SA-DNA hydrogel microspheres for the selective adsorption of uranyl ions (UO22+) in an economically viable manner. The microspheres were approximately 2 mm in size and contained numerous micrometer-sized pores to enhance mass transfer and fully expose the active sites. With DNA functioning as selective adsorption sites, the microspheres showed a significantly high affinity for UO22+ with a selectivity of 43.6 times that of vanadium ions, achieving unprecedented selective adsorption of UO22+. From the results, the synthesized adsorbent has exceptional uranium adsorption capability and excellent resistance against co-existing ions in seawater, and it is easily accessible and cost-effective. Analysis of interactions between the functional groups and ions revealed the coordination environment of UO22+. Density functional theory (DFT) calculations suggested that DNA provides favorable energetics for UO22+ binding and illustrated the U with P-O coordination effect. The results of this study are crucial for advancing the selective extraction of uranium from seawater. Moreover, such adsorbents with ultrahigh selectivity may be applied to extract other resource ions from seawater.

Chemical Synthesis – Porous frameworks for uranium extraction from seawater

Chemical Engineering Journal – Bio-inspired functionalization of electrospun nanofibers with anti-biofouling property for efficient uranium extraction from seawater.

Highlights

• Hyperbranched phosphate groups were grafted onto electrospun nanofibers.
• The proton transfer process could lead to the zwitterionic structures.
• The fiber adsorbents exhibited excellent adsorption performance towards UO22+.
• The nanofibers also showed anti-bacterial adhesion and anti-protein adhesion.
• The fiber adsorbents had good potential for the uranium extraction from seawater..

To tackle the challenges of traditional fiber adsorbents for uranium extraction, such as weak binding ability, low functional group density, and inefficient antifouling property, in this contribution we were inspired by the structures of a phospholipid and we grafted hyperbranched phosphate based zwitterionic groups onto the electrospun nanofibers with the following features: efficient uranium coordination sites, high content of accessible functional groups, and zwitterionic structures responsible for the antifouling property. We hypothesized that such nanofiber adsorbents could efficiently bind uranyl ions from complex seawater through our combination of electrospinning, bio-inspired grafting and hyperbranched functionalization. The material preparation, uranium adsorption performance, and anti-biofouling property were well investigated to understand the regulation strategy, structure–activity relationship, and adsorption mechanism of our nanofiber adsorbents. These results indicated that we put forward an applicable electrospun nanofiber adsorbent for practical uranium extraction from seawater.

Conclusions
In summary, the bio-inspired zwitterionic phosphate groups grafted electrospun nanofibers with hyperbranched structures were fabricated. On account of their specific binding groups and abundant accessible adsorption sites, the obtained ZP-PAN fibers could realize ultra-high uranium adsorption capacity (1294 mg g−1), large distribution coefficient kd (7.38 × 106 mL/g) and good uranium selectivity (13.3 times UO22+ uptake capacity than VO2+). The nanofiber adsorbents could be easily recovered

Abstract
The development of efficient adsorbents with anti-biofouling properties for uranium extraction from seawater is highly attractive to meet the growing demands for energy. However, traditional fiber adsorbents still suffer from the challenge of weak binding energy, low functional group density, and inefficient antifouling ability. Herein, inspired by the structures of phospholipid, the bio-inspired zwitterionic phosphate groups were created onto the electrospun nanofibers to manipulate the affinity with uranium and the anti-biofouling property. Additionally, hyperbranched grafting reaction together with thin diameters of the fibers were applied to significantly improve the available density of functional groups. The constructed hyperbranched zwitterionic phosphate groups functionalized nanofiber adsorbents (ZP-PAN fibers) exhibited high distribution coefficient kd (7.38 × 106 mL/g) and large adsorption capacity (1294.0 mg g−1) in the uranium-spiked seawater, surpassing most of reported polymeric adsorbents. ZP-PAN fibers also showed good selectivity against competitive cations and stable reusability. Owing to their zwitterionic structures, ZP-PAN fibers had satisfactory anti-adhesive ability toward bacteria and protein. Consequently, the uranium could be effectively extracted by ZP-PAN fibers from natural seawater with the extraction capacity of 8.1 mg g−1 after contacting with seawater for 15 days. This work demonstrates a new functionalization selection for nanofiber materials and provides a promising adsorbent in the practical uranium extraction from seawater.

Despite the long and effective development of seawater uranium extraction, there are still many noteworthy problems that hinder the development of seawater uranium extraction technology to a certain extent, especially its progress in industrialization. First, the stability of the uranium adsorbent in practical application limits its efficient and effective application. The factors destroying the cyclic stability of adsorbents are mainly the structural changes in the elution process and the destruction of adsorbent structure by the complex environment in seawater. When general porous adsorbents, especially COF and MOF, are used as uranium adsorbents, the pore structure and ligand sites tend to lose part of their activity after repeated strong acid and alkali treatments, resulting in a decrease in the adsorption capacity and an impact on the performance of the adsorbents. In addition, the high concentration of metal ions in seawater and the widespread presence of various microorganisms may also reduce the adsorption capacity by hindering the contact of uranyl ions with the adsorption sites. To address these issues, adsorption sites with stronger binding affinity and stable structures should be rendered, and the materials should be loaded onto highly stable substrates to minimize the effects on the structure and stability of the adsorbents during uranium extraction and material treatment. In addition, in order to cope with the interference of microorganisms in the ocean on uranium extraction, adsorbents with adsorbent sites doped or hybridized with antimicrobial components can be tailored, and biologically active sites can be introduced into the adsorbent to realize the antimicrobial function and adsorbent function at the same time. Second, the complex and variable marine environment and its large gap with the laboratory environment limit the commercialization of seawater uranium extraction. Since large-scale marine experiments require large doses of the adsorbent, the latter may itself become a marine pollution factor if not handled properly. Therefore, when considering the enhancement of adsorbent stability, not only should a single environment be taken into account, but the adsorbent should be stabilized within a specific range of environmental conditions. At the same time, the large number of other metal ions in seawater and the low concentration of uranium itself greatly reduce the selectivity and rate of adsorption. In order to increase the rate of uranium adsorption, methods by applying additional light or electric fields are becoming well known. For example, the use of marine photovoltaic power generation and offshore wind power generation at sea as part of a seawater uranium extraction project may be effective in improving both the efficiency of seawater uranium extraction and the efficiency of electricity utilization, and in reducing the energy loss due to long-distance transmission.