Extraction Of Uranium Research Articles

Toward a Low-Cost Uranium-Absorbing Material based on Nonwoven Fabrics and Photografting Technology

Amidoxime-functionalized polymeric adsorbents have attracted great interest for uranium extraction from seawater. However, the current graft polymerization method is time-consuming (2~6 h), wasteful in reagent, and hence not economical. Here,...

Opportunities and Challenges of Capacitive Deionization for Uranium Extraction from Seawater

Opportunities and Challenges of Capacitive Deionization for Uranium Extraction from Seawater

Advances in Adsorption Materials and Coordination Mechanism of Functional Groups for Uranium Extraction from Seawater

Advances in Adsorption Materials and Coordination Mechanism of Functional Groups for Uranium Extraction from Seawater

Solving the biofouling problem of uranium extraction from seawater by plasma technology

Plasma treatment can effectively kill microorganisms in seawater and solve the marine biofouling problem of U(vi) extraction.

Hydrazide and amidoxime dual functional membranes for uranium extraction from seawater

Amidoxime (AO)-based adsorbents are currently regarded as the most promising materials for extracting uranium (U) from seawater, but have limited adsorption capacities.

The preparation of spherical Dopamine/Carbon for the efficient removal of uranium

As Japan releases nuclear wastewater into the ocean, radioactive contamination has caused global concern. Among those radioactive contaminants, uranium(U) is one of the worst pollutants. This study prepares the spherical dopamine/carbon(DA/C) through a simple hydrothermal process to remove U(VI) from water. In adsorption, uranium ions are adsorbed on the material surface and gradually enter the material through the pores. U(VI) adsorption is a single molecule adsorption process, and the adsorption capacity of the DA/C is 30.4 mg/g at pH = 7.0 and 288 K. U(VI) adsorption depends on electrostatic attraction and complexation. The hydroxyl groups and amino groups of the DA/C can form complexes with U(VI) ions. The DA/C possesses excellent desorption and regeneration ability, which can be used for U(VI) removal and extract uranium from seawater. This study provides a new idea for enriching U(VI), which helps control radioactive pollution.

Distribution and migration of uranium, chromium, and accompanying metal(loid)s in soil-plants system around a uranium hydrometallurgical area

The extraction and utilization of uranium (U) ores have led to the release of significant amounts of potentially toxic metal(loid)s (PTMs) into the environment, constituting a grave threat to the ecosystem. However, research on the distribution and migration mechanism of U, chromium (Cr), and their accompanying PTMs in soil-plant system around U hydrometallurgical area remains insufficient and poorly understood. Herein, the distribution, migration, and risk level of PTMs were evaluated in soil and plant samples around U hydrometallurgical area, Northern Guangdong, China. The results demonstrated that the maximum content of U and Cr found in the analyzed soils were up to 84.2 and 238.9 mg/kg, respectively. These values far exceed the soil background values in China and other countries. The highest content of U (53.6 mg/kg) was detected in Colocasia antiquorum Schott, and the highest content of Cr (349.5 mg/kg) was observed in Pteridium aquilinum, both of which were enriched in their roots. The risk assessment of PTMs demonstrated that the study area suffered from severe pollution (PN > 3), especially from U, Cr, Th, and As, suggesting the non-negligible anthropogenic impacts. Hence, in light of the significant ecological hazard posed by the U hydrometallurgical area, it is imperative to implement appropriate restoration measures to ensure the human health and maintain the stability of the ecosystem.

Capacitive deionization of uranium mediated by dioxygen functionalities in the C = O = C = O segment of polyacrylic acid-functionalized graphene aerogel

The extraction of uranium is crucial for sustaining a consistent nuclear fuel cycle, yet the task of isolating uranyl ions from aqueous solutions presents formidable challenges. Herein, a PAA/GO aerogel was developed using polyacrylic acid-functionalized graphene, wherein the C = O = C = O segment's dual oxygen served both as electrodes for capacitive deionization and as sites for charge transfer and uranyl capture, effectively purifying uranium mine wastewater. Furthermore, under the stringent experimental conditions set at 298 K and a pH of 5.5, the PAA/GO composite demonstrated an impressive adsorption capacity of 898.7 mg g−1. When this composite was further amalgamated into the CDI architecture, it exhibited an impressive 92 % uranium extraction from genuine mine effluent at an unwavering potential of 0.9 V. Through density functional theory (DFT) analyses, the adsorption energies of [UO2(H2O)5]2+ with the PAA/GO composite involving C = O = C = O ligands displayed the highest value compared with PAA and PAA/GO composite (involving monodentate and bidentate ligands). The Bader charge analysis further indicating the greatest charge loss in the uranium ion. In conclusion, the novel PAA/GO aerogel 3D framework with its specific C = O = C = O regional chain sets a pioneering standard in uranium extraction techniques, showcasing unprecedented efficiency in UO22+ removal from aqueous solutions.

Fabrication of Carboxylate-Functionalized 2D MOF Nanosheet with Caged Cavity for Efficient and Selective Extraction of Uranium from Aqueous Solution.

The efficient removal of radioactive uranium from aqueous solution is of great significance for the safe and sustainable development of nuclear power. An ultrathin 2D metal-organic framework (MOF) nanosheet with cavity structures was elaborately fabricated based on a calix[4]arene ligand. Incorporating the permanent cavity structures on MOF nanosheet can fully utilize its structural characteristics of largely exposed surface area and accessible adsorption sites in pollutant removal, achieving ultrafast adsorption kinetics, and the functionalized cavity structure would endow the MOF nanosheets with the ability to achieve preconcentration and extraction of uranium from aqueous solution, affording ultrahigh removal efficiency even in ultra-low concentrations. Thus, more than 97% uranium can be removed from the concentration range of 50-500µgL-1 within 5min. Moreover, the 2D nano-material exhibits ultra-high anti-interference ability, which can efficiently remove uranium from groundwater and seawater. The adsorption mechanism was investigated by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) analysis, and density functional theory (DFT) calculations, which revealed that the cavity structure plays an important role in uranium capture. This study not only realizes highly efficient uranium removal from aqueous solution but also opens the door to achieving ultrathin MOF nanosheets with cavity structures, which will greatly expand the applications of MOF nanosheets.

Solar-powered simultaneous highly efficient seawater desalination and highly specific target extraction with smart DNA hydrogels.

Obtaining freshwater and important minerals from seawater with solar power facilitates the sustainable development of human society. Hydrogels have demonstrated great solar-powered water evaporation potential, but highly efficient and specific target extraction remains to be expanded. Here, we report the simultaneous highly efficient seawater desalination and specific extraction of uranium with smart DNA hydrogels. The DNA hydrogel greatly promoted the evaporation of water, with the water evaporation rate reached a high level of 3.54 kilograms per square meter per hour (1 kilowatt per square meter). Simultaneously, uranyl-specific DNA hydrogel exhibited a high capture capacity of 5.7 milligrams per gram for uranium from natural seawater due to the rapid ion transport driven by the solar powered interfacial evaporation and the high selectivity (10.4 times over vanadium). With programmable functions and easy-to-use devices, the system is expected to play a role in future seawater treatment.

The photocatalytic extraction of U(VI) by CdS/g-C3N4 cellulose film

Photocatalysis is considered as a promising way for separating and extracting uranium. However, powder catalysts used in most studies are hard to be recovered and reused in practical application. Herein, a CdS/g-C3N4 cellulose membrane (CCM) was successfully fabricated for the photocatalytic extraction of uranium. It was revealed that the incorporation of catalyst in membrane remarkably enhanced the separation and transfer of charge carriers. CCM showed outstanding performance of uranium extraction under air conditions without sacrificial reagent. Under light irradiation, ∼95 % of 15 mL 0.1 mM uranyl could be removed within 140 min and a high extraction capacity of 1599.72 mg/g could be achieved. After four cycles, CCM still remained high reactivity and could remove ∼ 85 % uranyl from aqueous solution. During the photocatalytic reactions, U(VI) was mainly reduced by •O2– radicals, and •OH also contributed to the removal of uranium. Owing to the generation of reactive oxygen species, CCM exhibited excellent antifouling property. The results suggest CCM can be a good candidate for separating and extracting uranium from solutions.

Phytate-modified MOFs grown on carbon nanotubes for efficient adsorption of uranium(Ⅵ) from seawater

The selective separation of uranium through adsorption remains a formidable challenge. Therefore, a one-step hydrothermal method was initially employed to anchor the metal-organic framework onto carbon nanotube oxides (NH2-MIL-101@MWCNT, the BET surface area of 1017.63 m2·g−1). Subsequently, a surface-functionalized composite nanoparticle (named PA-MIL-101@MWCNT, the BET surface area of up to 368.14 m2·g−1) was synthesized through phosphorylation via the Mannich reaction for uranium adsorption. Batch adsorption experiments unequivocally demonstrated that the modification with phytic acid led to a significant improvement in the uranium adsorption capacity of the composite material, achieving a maximum adsorption capacity of 599.77 mg·g−1. The initial adsorption rate of PA-MIL-101@MWCNT was exceptionally rapid, achieving 73.84 % of the maximum adsorption capacity within 10 min. Adsorption kinetics and thermodynamics indicated that uranium adsorption follows a single-molecule chemisorption mechanism. PA-MIL-101@MWCNT exhibits exceptional resistance to ionic interference within natural seawater, demonstrating excellent stability and recyclability. XPS and DFT calculations strongly supported the notion that the uranium adsorption mechanism was associated with the oxygen atoms in the PO and P-O functional groups. These findings suggest that PA-MIL-101@MWCNT can be considered an excellent material for uranium extraction from seawater, which is significant to the sustainable utilization of nuclear energy materials.

Recovery of uranium from conversion production sludge by leaching with nitric acid and subsequent ion-exchange concentration

Physicochemical studies of the sludge of uranium conversion production were carried out to determine the possibility of its processing and return of uranium to the nuclear fuel cycle. It has been established that the sludge was mainly represented by calcium compounds: CaSO4·2H2O (60.1 wt%), CaCO3 (25.1 wt%), CaF2 (13.7 wt%), and silicon dioxide (1.2 wt%). The content of uranium in the sludge was 0.15 wt%. It was shown that it was possible to achieve high degrees of uranium extraction from the sludge using nitric acid as a leaching agent. The use of phosphorus-containing ion-exchanger Tulsion CH93 ensured the effective concentration of uranium from highly acidic pregnant leach solutions. The full dynamic exchange capacity achieved 15.7 kg m−3. The degree of uranium desorption by ACBM (ammonium carbonate/bicarbonate mixture) solutions was 83%. The final product was ammonium uranyl phosphate hydrate NH4UO2PO4∙3H2O with a uranium content of 52.5 wt%.

Efficient and sustainable extraction of uranium from aquatic solution using biowaste-derived active carbon.

Efficient and cost-effective biosorbents derived from biowaste are highly demanding to handle various environmental challenges, and demonstrate the remarkable synergy between sustainability and innovation. In this study, the extraction of uranium U(VI) was investigated on biowaste activated carbon (BAC) obtained by chemical activation (phosphoric acid) using Albizia Lebbeck pods as biowaste. The biowaste powder (BP), biowaste charcoal (BC) and BAC were evaluated by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) with nitrogen adsorption for thermal properties, chemical structures, porosity and surface area, respectively. The pHPZC for acidic or basic nature of the surface and X-ray diffraction (XRD) analysis were performed for BAC. The morphological and elemental analysis were performed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The extraction of uranium U(VI) ions from aqueous solutions using BAC as sorbent was investigated by using different variables such as pH, contact time, initial uranium U(VI) concentration and BAC dose. The highest adsorption (90.60% was achieved at 0.5g BAC dose, 2h contact time, pH 6, 10ppm initial U(VI) concentration and with 200rpm shaking speeds. The production of this efficient adsorbent from biowaste could be a potential step forward in adsorption of uranium to meet the high demand of uranium for nuclear energy applications.

Facilitating charge separation and migration of conjugated microporous polymers via skeleton isomerism engineering for photocatalytic reduction of uranium (VI)

Photoreduction of highly toxic and high-mobility UVI into insoluble UIV via conjugated microporous polymers (CMPs) is an effective way to extract uranium from highly acidic wastewater. Nevertheless, undesirable charge separation and migration, as well as rapid reverse charge recombination resulted in unsatisfactory photocatalytic activity of most CMPs. Herein, a pair of D-A CMPs for uranium photocatalytic reduction was developed by modulating skeleton isomerism through isomeric building blocks, named PQ-TPM (with phenanthrenequinone skeleton) and AQ-TPM (with anthraquinone skeleton). Interestingly, compared with anthraquinone skeleton CMP, phenanthrenequinone skeleton CMP can inhibit reverse charge recombination while promoting charge separation and migration due to its stronger built-in electric field and larger dipole moment. Therefore, PQ-TPM achieves an ultra-high photocatalytic UVI removal efficiency of 80.0 % within 180 min visible-light irradiation even under strongly acidic conditions (pH = 2), which was superior to AQ-TPM (30.0 %) and most reported CMPs. This study provides an unconventional concept and an emerging strategy for exploring outstanding CMPs photocatalysts for efficient processing of radionuclides.

Phosphate and amphiphilic-functionalized luffa with anti-biofouling property for efficient uranium extraction from seawater

The attachment of marine organisms is the main problem of extracting uranium from seawater. In this article, phosphate groups were grafted to the surface of luffa (LUP), and an antifouling material for uranium extraction from seawater (LUPPC) was prepared by ionic initiated free radical polymerization with amphiphilic polymers. The LUPPC expressed great uranium adsorption and antifouling property. After soaking in small crescent diamond algae for 10 days, the LUPPC surface had almost no seaweed attachment compared with luffa and LUP. According to the DFT theory, the P-U bond length is 2.44 Å and the adsorption energy with uranium is −219.63 kcal mol−1. The short bond length and high binding energy indicate the excellent adsorption properties of the LUPPC.

Enhanced and selective uranium extraction onto electrospun nanofibers by regulating the functional groups and photothermal conversion performance

Uranium extraction from natural seawater is critical to addressing the shortage of uranium resources, but it is a giant challenge. The amidoxime-based adsorbent is regarded as one of the most promising materials for uranium capture, whereas still suffers from low adsorption site utilization and poor selectivity toward U(VI) against V(V). Herein, hyperbranched amidoxime group grafted photothermal electrospun fibers (AOPEI-C-PAN fibers) were reported for highly efficient uranium extraction from seawater. Carbon nanotubes (CNTs) were blended into the electrospun fibers to introduce the photothermal character. Hyperbranched grafting could improve the content of the amidoxime group and bring an assistant group (the amine group). Owing to the large content of functional groups, synergetic coordination interaction and photothermal conversion ability, the novel fiber adsorbents realized a fast adsorption rate (shortening the equilibrium time to 36 h from 60 h compared with the dark condition), high uranium uptake (1738.5 mg g−1 from the Langmuir model) from the uranium spiked seawater and excellent selectivity in U/V binary system (selectivity coefficient = 85.8). Furthermore, Ag nanoparticles could also be loaded onto the CNTs to endow the fibers with antibacterial activity, thereby preventing biofouling. As a result, the uranium extraction capacity of the fiber adsorbent reached 9.54 mg g−1 after 28 days’ simulated sunlight irradiation of contact with circular seawater, which is 62.0 % higher than that under dark condition. This study reveals that AOPEI-C-PAN fiber adsorbent holds great potential in practical uranium extraction applications.

Intensified extraction and stripping of uranium using membrane dispersion microextractor

The extraction and stripping of uranium(VI) using membrane dispersion microextractor were investigated in high phase ratio. The effects of residence time, aqueous phase flowrates and organic phase flowrates, as well as nitric acid and the extractant concentration on the stage efficiency were evaluated. With the increase of aqueous phase flowrate and organic phase, the efficiency firstly decreased and then increased. Both the extraction efficiency and stripping efficiency can reach >90 % at high phase ratio within 10 s. The efficiency decreased with the increase of nitric acid in aqueous phase, whereas the efficiency increased with the increase of tributyl phosphate (TBP) concentration. Finally, mass transfer characteristic in extraction process in membrane dispersion microextractor was discussed. The overall mass transfer coefficient in membrane dispersion microextractor could reach 0.13 s−1 at A:O = 5:1 and 0.058 s−1at high A:O ratio of 40:1.

Costly effective bioleaching of valuable metals from low grade ore using Aspergillus nidulans

This research investigated the feasibility of employing organic acids, like citric acid, produced by Aspergillus nidulans MT355567 in a bioleaching process to recover uranium (U) from a low-grade rock sample. The optimal conditions for fungal growth and maximum citric acid (CA) synthesis across three distinct media were determined. The maximum citric acid concentration was produced on medium made from wheat bran (83%) and tea waste (77%). An investigation was carried out to see how citric acid and, by consequence, uranium bioleaching affinity, were affected by varying carbon sources, nitrogen sources, pH, temperature, incubation period, ore particle size, and the solid–liquid ratio. At 25 °C and a pH of 5.0, media containing 100 g/L of sucrose as a carbon source and peptone as a nitrogen source made the highest yield of citric acid and U bioleaching. Higher U bioleaching was achieved with ore particles 0.075 mm at a ratio of 2 g/L after only 30 min of contact with the fungal filtrate. Iron interference has a negative impact on uranium extraction. Interestingly, none of the conditions applied to enhance CA synthesis and U-bioleaching caused iron (Fe) dissolution. Based on these findings, it appears that bioleaching using A. nidulans MT355567 metabolic products is a promising economic and ecofriendly technology for extracting uranium from low-grade ore that might be adopted on a pilot scale.Graphical abstractsummarizing the experimental workflow for bioleaching of uranium from low-grade ore using citric acid produced by Aspergillus nidulans. The process involved optimizing A. nidulans growth and citric acid biosynthesis, evaluating factors influencing bioleaching activity of the acid metabolite solutions, and finally applying the optimized conditions to bioleach uranium from the ore sample. The schematic illustrates the key steps and the optimal condition for Aspergillus nidulans growth medium preparation using agricultural wastes, downstream application of metabolite synthesized for uranium bioleaching

Preparation of novel polyvinyl alcohol–carbon nanotubes containing imidazolyl ionic liquid/chitosan hydrogel for highly efficient uranium extraction from seawater

A novel polyvinyl alcohol–carbon nanotube containing an imidazolyl ionic liquid/chitosan composite hydrogel (termed CBCS) was prepared for highly selective uranium adsorption from seawater. The results show that CBCS has good adsorption properties for uranium within the pH range of 5.0–8.0. Kinetics and thermodynamics experiments show that the theoretical maximum adsorption capacity of CBCS to U(VI) is 496.049 mg/g (288 K, pH = 6.0), indicating a spontaneous exothermic reaction. Mechanism analysis shows that the hydroxyl group, amino group, and CN bond on the surface of CBCS directly participate in uranium adsorption and that the dense pores on the surface of CBCS play an important role in uranium adsorption. The competitive adsorption experiment shows that CBCS has excellent uranium adsorption selectivity. In addition, CBCS exhibits good reusability. After five adsorption–desorption cycles, the uranium adsorption rate of CBCS can still reach >98 %. Hence, CBCS has excellent potential for uranium extraction from seawater.