This is second paper summarizing the study on the hydrous titanium oxide absorbent for extracting uranium fromseawater. The investigation is performed by means of X- ray photoelectronic energy spectroscopy for chemica...This is second paper summarizing the study on the hydrous titanium oxide absorbent for extracting uranium fromseawater. The investigation is performed by means of X- ray photoelectronic energy spectroscopy for chemical analysis ( ESC A ) , determination of surface hydroxy radical, Fourier-transfer infrared spectrophotometry (FT-IR ) , electron paramagnetic resonance (EPR), inductively coupled Plasma torch (ICP), etc. The emphasis is laid upon the exploration of HTO surface and a discussion about the adsorption micromechanism.展开更多
The novel pulsed liquid chromatography radionuclide separation method presented here provides a new and promising strategy for the extraction of uranium from seawater.In this study,a new chromatographic separation met...The novel pulsed liquid chromatography radionuclide separation method presented here provides a new and promising strategy for the extraction of uranium from seawater.In this study,a new chromatographic separation method was proposed,and a pulsed nuclide automated separation device was developed,alongside a new chromatographic column.The length of this chromatographic column was 10 m,with an internal warp of 3 mm and a packing size of 1 mm,while the total separation units of the column reached 12,250.The most favorable conditions for the separation of nuclides were then obtained through optimizing the separation conditions of the device:Sample pH in the column=2,sample injection flow rate=5.698 mL/min,chromatographic column heating temperature=60℃.Separation experiments were also carried out for uranium,europium,and sodium ions in mixed solutions;uranium and sodium ions in water samples from the Ganjiang River;and uranium,sodium,and magnesium ions from seawater samples.The separation factors between the different nuclei were then calculated based on the experimental data,and a formula for the separation level was derived.The experimental results showed that the separation factor in the mixed solution of uranium and europium(1:1)was 1.088,while achieving the initial separation of uranium and europium theoretically required a 47-stage separation.Considering the separation factor of 1.50for the uranium and sodium ions in water samples from the Ganjiang River,achieving the initial separation of uranium and sodium ions would have theoretically required at least a 21-stage separation.Furthermore,for the seawater sample separation experiments,the separation factor of uranium and sodium ions was 1.2885;therefore,more than 28 stages of sample separation would be required to achieve uranium extraction from seawater.The novel pulsed liquid chromatography method proposed in this study was innovative in terms of uranium separation and enrichment,while expanding the possibilities of extracting uranium from seawater through chromatography.展开更多
Direct collection of uranium from low uranium systems via adsorption remains challenging.Fibrous sorbent materials with amidoxime(AO)groups are promising adsorbents for uranium extraction from seawater.However,low AO ...Direct collection of uranium from low uranium systems via adsorption remains challenging.Fibrous sorbent materials with amidoxime(AO)groups are promising adsorbents for uranium extraction from seawater.However,low AO adsorption group utilization remains an issue.We herein fabricated a branched structure containing AO groups on polypropylene/polyethylene spun-laced nonwoven(PP/PE SNW)fibers using grafting polymerization induced by radiation(RIGP)to improve AO utilization.The chemical structures,thermal properties,and surface morphologies of the raw and treated PP/PE SNW fibers were studied.The results show that an adsorptive functional layer with a branching structure was successfully anchored to the fiber surface.The adsorption properties were investigated using batch adsorption experiments in simulated seawater with an initial uranium concentration of 500μg·L^(−1)(pH 4,25℃).The maximum adsorption capacity of the adsorbent material was 137.3 mg·g^(−1)within 24 h;moreover,the uranyl removal reached 96%within 240 min.The adsorbent had an AO utilization rate of 1/3.5 and was stable over a pH range of 4–10,with good selectivity and reusability,demonstrating its potential for seawater uranium extraction.展开更多
The radioactivity of uranium in radioactive coal bottom ash（CBA） may be a potential danger to the ambient environment and human health. Concerning the limited research on the distribution and mode of occurrence of u...The radioactivity of uranium in radioactive coal bottom ash（CBA） may be a potential danger to the ambient environment and human health. Concerning the limited research on the distribution and mode of occurrence of uranium in CBA, we herein report our investigations into this topic using a number of techniques including a five-step Tessier sequential extraction, hydrogen fluoride（HF） leaching, Siroquant（Rietveld） quantification, magnetic separation, and electron probe microanalysis（EPMA）. The Tessier sequential extraction showed that the uranium in the residual and Fe–Mn oxide fractions was dominant（59.1%and 34.9%, respectively）. The former was mainly incorporated into aluminosilicates,retained with glass and cristobalite, whereas the latter was especially enriched in the magnetic fraction, of which about 50% was present with magnetite（Fe_3O_4） and the rest in other iron oxides. In addition, the uranium in the magnetic fraction was 2.6 times that in the non-magnetic fraction. The experimental findings in this work may be important for establishing an effective strategy to reduce radioactivity from CBA for the protection of our local environment.展开更多
Amid the global energy transition and pursuit of ″dual-carbon″ goals, nuclear energy has attracted growing attention as a lowcarbon, high-efficiency power source. However, the limited terrestrial uranium reserves ar...Amid the global energy transition and pursuit of ″dual-carbon″ goals, nuclear energy has attracted growing attention as a lowcarbon, high-efficiency power source. However, the limited terrestrial uranium reserves are only sufficient to sustain demand for a few decades.展开更多
The rapid development of advanced techniques for selective and efficient U(Ⅵ) extraction from aqueous solutions is essential for addressing U(Ⅵ) environmental pollution and energy issues. Here, we share recent progr...The rapid development of advanced techniques for selective and efficient U(Ⅵ) extraction from aqueous solutions is essential for addressing U(Ⅵ) environmental pollution and energy issues. Here, we share recent progress in U(Ⅵ) extraction from aqueous solutions, especially the most frequently applied techniques such as adsorption, catalysis(photocatalysis, piezocatalysis, and electrocatalysis), chemical deposition, and reduction by zero-valent metal particles. We attempt to elucidate the strategies and various mechanisms that contribute to the enhancement of selective U(Ⅵ) extraction. At the end of our review, we highlight the outlook, challenges, and prospects for the development of this field.展开更多
1 Introduction Nuclear energy is crucial not only for the fast development of industry but also for the achievement of CO_(2)emission peaking and carbon neutrality.The rapid increase of nuclear energy utilization in C...1 Introduction Nuclear energy is crucial not only for the fast development of industry but also for the achievement of CO_(2)emission peaking and carbon neutrality.The rapid increase of nuclear energy utilization in China requires a continuously nuclear fuel supply.However,the uranium resources on the land can only maintain about 70-100 years for nuclear power plants.There are~4.5×10^(10) t of uranium in the ocean.However,the uranium concentration in natural seawater is quite low(~3.3 ppb),and other competing cations affect uranium selective sorption obviously.More importantly,the bacteria and microorganisms in marine environments occupy the groups and active sites of materials,thereby decreasing the sorption ability[1].Uranium extraction from seawater is considered one of the“7 chemical separations and challenges to change the world”[2].展开更多
Uranium plays a pivotal role in nuclear energy production, and extracting it from seawater offers a promising solution to alleviate shortages in land-based uranium resources. However, the marine environment with ultra...Uranium plays a pivotal role in nuclear energy production, and extracting it from seawater offers a promising solution to alleviate shortages in land-based uranium resources. However, the marine environment with ultra-low uranium concentrations, high salinity, and microbial activity poses significant extraction challenges, compounded by selectivity and cost limitations in current methods. In the present investigation, an anti-biofouling amino oximefunctionalized collagen/sodium alginate aerogel(CF-AO/SA) was fabricated using leather waste-derived collagen. The dual cross-linked CF-AO/SA network, enhanced by Zn2+incorporation, showed improved structural stability and antibacterial properties, as well as high uranium adsorption capacity, selectivity, and reusability. It achieved 320.7 mg g-1in 14 ppm uranium solution and maintained 78.6% removal efficiency after five cycles. Additionally, the removal rate of uranium was 89% in simulated seawater. Field tests in Zhuhai's Jinwan District(113.35° E, 21.99° N) showed 5.16 mg g-1uranium adsorption and excellent mechanical strength after 30 days in seawater. Furthermore, the production cost of CF-AO/SA was estimated at $3.652 per kilogram, which is lower than other reported adsorbents. The newly developed bio-based aerogel beads have substantial potential for practical applications for uranium capture in seawater and provide a novel high-value utilization way for leather wastes.展开更多
The development of novel metal-organic frameworks(MOFs)as solid adsorbents for rapid and efficient extraction of uranium from natural seawater is a long-term pursuit,yet remains challenging.In this work,we have prepar...The development of novel metal-organic frameworks(MOFs)as solid adsorbents for rapid and efficient extraction of uranium from natural seawater is a long-term pursuit,yet remains challenging.In this work,we have prepared four two-dimensional(2D)vinylene-linked cyclic trinuclear units(CTUs)based MOFs.The metal nodes in the skeleton can be regulated,resulting in two Ag-CTU and two Cu-CTU-based MOFs with similar 2D hexagonal structures.These MOFs exhibit not only good stability in acid/base,γ-ray irradiation and natural seawater but also feature excellent anti-biofouling properties against five marine bacteria with inhibition rates as high as~99%.Interestingly,the alteration of Ag(I)to Cu(I)remarkably enhances the uranium sorption capacity due to the reduction of soluble U(VI)to insoluble U(IV)triggered by the chemical and photo-redox reaction of Cu-CTU.Due to the multiple functions,the Cu-CTU-based MOF delivers the best overall performance for uranium extraction from natural seawater with a high adsorption capacity of 7.96 mg g^(-1)and adsorption rate of~1.00 mg g^(-1)day^(-1),which is much higher than most of reported representative solid adsorbents.Our work paves a new way for rationally designing synergistic MOFs with superior performance for extracting uranium from natural seawater.展开更多
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 ...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,amidoxime-functionalized adsorbents based on low-cost polypropylene melt-blown nonwoven fabric(MBF)are produced by a simple,fast and also low-cost surface photografting technology,by which more than 80%of reagents can be saved and grafting time can be reduced to 3 min.The fabricated adsorbents retain their mechanical properties and exhibit excellent uranium adsorption properties,with a maximum uranium adsorption capacity of 400 mg g-1 when the monomer ratio of AN to AA is 8:2.Moreover,we showed that the adsorbents could be either reused or simply incinerated for uranium recovery.The photografting technology has great potential for low-cost,continuous industrial production of uranium-adsorbing material.展开更多
Seawater contains approximately 4.5 billion tons of dissolved uranium,making it a significant potential source of nuclear fuel.However,the low uranium concentration,interference from competing ions,and the complex mar...Seawater contains approximately 4.5 billion tons of dissolved uranium,making it a significant potential source of nuclear fuel.However,the low uranium concentration,interference from competing ions,and the complex marine environment pose major challenges to the economic feasibility of uranium extraction.Among various extractionmethods,adsorption is considered the most promising due to its low cost,simple operation,and strong adaptability tomarine conditions.Current research primarily focuses on developing high-performance adsorbent materials,including polymers,MXene,framework materials,and bio-based adsorbents.To optimize adsorbent performance,efforts are directed toward enhancing adsorption selectivity,increasing functional group utilization,improving adsorption kinetics,and strengthening environmental adaptability.Researchers have explored various strategies to achieve these goals,such as ion imprinting,functional group engineering,and the application of external energy fields(e.g.,light,electric fields)to enhance adsorption efficiency and uranium recovery.Although significant progress has been made in laboratory settings,real-world marine applications still face critical challenges,including biofouling resistance,large-scale engineering deployment,and efficient recovery.Future research efforts should focus on developing novel adsorbents,advancing external field-assisted extraction technologies,and optimizing large-scale engineering applications to enhance the practicality of seawater uranium extraction,ultimately making it a viable source of nuclear fuel.展开更多
Addressing the challenges of uranium extraction from seawater(UES)requires innovative strategies to overcome ultralow concentration(3.3 ppb)and thermodynamic limits.Herein,we propose a regioisomeric engineering strate...Addressing the challenges of uranium extraction from seawater(UES)requires innovative strategies to overcome ultralow concentration(3.3 ppb)and thermodynamic limits.Herein,we propose a regioisomeric engineering strategy to design vinylene-linked covalent organic frameworks(COFs)for synergistic adsorption-photocatalytic UES.Two isomeric COFs,β-PTTN-AO andα-PNNB-AO,were synthesized by tuning the substitution positions of amidoxime(AO)groups on olefin bonds.Theβ-PTTN-AO isomer achieves a remarkable UES capacity of 12.74±0.21 mg·g^(-1)in nature seawater,surpassing itsα-positioned counterpart(8.9±0.18 mg·g^(-1))and outperforming most reported photocatalysts.Combined experiments and density functional theory(DFT)theoretical studies correlate regioisomeric configurations with electronic structure modulation and photocatalytic activity.Specifically,β-PTTN-AO enhanceπ-electron delocalization and strengthen built-in electric fields,promoting exciton dissociation,charge separation,and uranium reduction.This work establishes a molecular design paradigm for COF photocatalysts,advancing sustainable nuclear energy through structural isomerism.展开更多
An amidoxime-based ultra-high molecular weight polyethylene （UHMWPE） fibrous adsorbent was successfully prepared by T-irradiation-induced graft copolymerization of acrylonitrile （AN） and acrylic acid （AA）, follo...An amidoxime-based ultra-high molecular weight polyethylene （UHMWPE） fibrous adsorbent was successfully prepared by T-irradiation-induced graft copolymerization of acrylonitrile （AN） and acrylic acid （AA）, followed by amidoximation. The grafting of AN and AA on the UHMWPE fiber and the amidoximation of the grafted fiber were confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The mechanical property of the original and modified UHMWPE fibers was compared by single-filament strength test. The adsorption property of the UHMWPE fibrous adsorbent was evaluated by adsorption test in uranyl nitrate solution and seawater. The surface of the modified UHMWPE fibers was covered by the grafting layer and became rough. The tensile strength of the amidoxime-based UHMWPE fibrous adsorbent was influenced by the absorbed dose and hydrochloric acid elution, but was independent of the grafting yield and amidoximation. The uranium adsorption amount of the amidoxime-based UHMWPE fibrous adsorbent after immersing in seawater for 42 days was 2.3 mg-U/g.展开更多
Photocatalytic uranium extraction from radioactive nuclear wastewater and seawater is critical for promoting the sustainable advancement of nuclear industry,but the complexity of real-world environments,particularly t...Photocatalytic uranium extraction from radioactive nuclear wastewater and seawater is critical for promoting the sustainable advancement of nuclear industry,but the complexity of real-world environments,particularly the occurrence of anoxic and oxygen-enriched states,presents significant challenges to effective uranium extraction.Here,a layered hollow core–shell structure of Bi_(2)O_(3)/g-C_(3)N_(4)Z-scheme heterojunction photocatalyst has been designed and successfully applied for photocatalytic uranium extraction in both aerobic and oxygen-free conditions,and the extraction efficiency of uranium can reach 98.4%and 99.0%,respectively.Moreover,the photocatalyst still has ultra-high extraction efficiency under the influence of pH,inorganic ions,and other factors.The exceptional capability for uranium extraction is on the one hand due to the distinctive hollow core–shell architecture,which furnishes an abundant quantity of active sites.On the other hand,benefiting from the suitable band gap structure brought by the construction of Z-scheme heterojunction,Bi_(2)O_(3)/g-C_(3)N_(4)exhibits current densities(1.00μA/cm^(2))that are 5.26 and 3.85 times greater than Bi_(2)O_(3)and g-C_(3)N_(4),respectively,and the directional migration mode of Z-scheme carriers significantly prolongs the lifetime of photogenerated charges(1.53 ns),which separately surpass the pure samples by factors of 5.10 and 3.19.Furthermore,the reaction mechanism and reaction process of photocatalytic uranium extraction are investigated in the presence and absence of oxygen,respectively.展开更多
Porphyrinoid metal-organic frameworks(MOFs)with dual effective uranium uptake sites were synthesized through combined insitu and post-synthetic method.The MOF10@5 demonstrates the uptake amount of uranium reaches 1476...Porphyrinoid metal-organic frameworks(MOFs)with dual effective uranium uptake sites were synthesized through combined insitu and post-synthetic method.The MOF10@5 demonstrates the uptake amount of uranium reaches 1476 mg/g under visiblelight irradiation.The PN-MOF10@5 with dual uranyl uptake sites yields the amount of extracting uranyl of 1590 mg/g under visible-light irradiation.The density functional theory(DFT)calculations reveal strong interaction between uranyl and dual uranyl effective active sites.These MOFs demonstrate a powerful synthesis strategy for uranium extraction materials with dual effective active sites.展开更多
Efficient and selective extraction of uranium(U(VI))from seawater is essential for sustainable nuclear power production.This study reports a novel adsorbent zeolitic imidazolate framework(ZIF)-67@SiO_(2)-A/polyacrylam...Efficient and selective extraction of uranium(U(VI))from seawater is essential for sustainable nuclear power production.This study reports a novel adsorbent zeolitic imidazolate framework(ZIF)-67@SiO_(2)-A/polyacrylamide(PAM)which was synthesized by grafting the core–shell metal–organic frameworks(MOFs)-based nanostructures coated with the 3-aminopropyl triethoxysilane(APTES)functionalized SiO_(2)(SiO_(2)-A)onto PAM hydrogel.The SiO_(2) shell was grown on the surface of MOF,which improved the acid-base resistance of MOF.The introduction of ZIF-67@SiO_(2)-A enhances the specific surface area and adsorption efficiency of the PAM.The ZIF-67@SiO_(2)-A/PAM shows remarkable adsorption capacity,fast adsorption kinetics,and good reusability for uranium.It has excellent adsorption property(6.33 mg·g^(-1),30 d)in natural seawater.The X-ray photoelectron spectroscopy(XPS),Fourier transform infrared(FTIR),energy dispersive spectroscopy(EDS)mappings,and density functional theory reveal that the coordination by N and O in ZIF-67@SiO_(2)-A/PAM with uranium is the main mechanism of uranium adsorption.Thus,ZIF-67@SiO_(2)-A/PAM has great potential to capture uranium from natural seawater.展开更多
The laser-induced optical fiber fluorimetry has been used for the first time to analyse the concentration of uranium(VI) in the kinetic studies on the extraction of uranium(VI) between 0.5 mol/L H_3PO_4 solution and H...The laser-induced optical fiber fluorimetry has been used for the first time to analyse the concentration of uranium(VI) in the kinetic studies on the extraction of uranium(VI) between 0.5 mol/L H_3PO_4 solution and HDEHP-cyclohexane system with Lewis cell. The effects of stirring speed, temper- ature and concentration of uranium(VI) and HDEHP on the rate of extraction were examined. These data show that the extraction rate of uranium(VI) in this system is controlled by the chemical reaction process at the interface. The rate equations and the rate constants of the forward and reverse ex- tractions were obtained. The mechanism of the extraction has been discussed.展开更多
We study here the response of photonic hydrogels(PHs),made of photonic crystals of homogeneous silica particles in polyacrylamide hydrogels(SPHs),to the uranyl ions 22 UO_(2)^(2+) in aqueous solutions.It is found that...We study here the response of photonic hydrogels(PHs),made of photonic crystals of homogeneous silica particles in polyacrylamide hydrogels(SPHs),to the uranyl ions 22 UO_(2)^(2+) in aqueous solutions.It is found that the reflection spectra of the SPH show a peak due to the Bragg diffraction,which exhibits a blue shift in the presence of 22 UO_(2)^(2+).Upon exposure to the SPH,22 UO_(2)^(2+)gets adsorbed on the SPH and forms complex coordinate bonds with multiple ligands on the SPH,which causes shrinking of hydrogel and leads to the blue shift in the diffraction peak.The amount of the blue shift in the diffraction peak increases monotonically up to 22 UO_(2)^(2+)concentrations as high as 2300μM.The equilibration time for the shift in the Bragg peak upon exposure to 22 UO_(2)^(2+)is found to be~30 min.These results are in contrast to the earlier reports on photonic hydrogels of inhomogeneous microgel particles hydrogel(MPH),which shows the threshold 22 UO_(2)^(2+)concentration of~600μM,below which the diffraction peak exhibits a blue shift and a change to a red shift above it.The equilibration time for MPH is~300 min.The observed monotonic blue shift and the faster time response of the SPH to 22 UO_(2)^(2+)as compared to the MPH are explained in terms of homogeneous nature of silica particles in the SPH,against the porous and polymeric nature of microgels in the MPH.We also study the extraction of 22 UO_(2)^(2+)from aqueous solutions using the SPH.The extraction capacity estimated by the arsenazo-III analysis is found to be 112 mM/kg.展开更多
文摘This is second paper summarizing the study on the hydrous titanium oxide absorbent for extracting uranium fromseawater. The investigation is performed by means of X- ray photoelectronic energy spectroscopy for chemical analysis ( ESC A ) , determination of surface hydroxy radical, Fourier-transfer infrared spectrophotometry (FT-IR ) , electron paramagnetic resonance (EPR), inductively coupled Plasma torch (ICP), etc. The emphasis is laid upon the exploration of HTO surface and a discussion about the adsorption micromechanism.
基金the Natural Science Foundation of Jiangxi Province,China(No.20202BABL203004)the Opening Project of the State Key Laboratory of Nuclear Resources and Environment(East China University of Technology)(No.2022NRE23)the Opening Project of Jiangxi Province Key Laboratory of Polymer Micro/Nano Manufacturing and Devices(No.PMND202101).
文摘The novel pulsed liquid chromatography radionuclide separation method presented here provides a new and promising strategy for the extraction of uranium from seawater.In this study,a new chromatographic separation method was proposed,and a pulsed nuclide automated separation device was developed,alongside a new chromatographic column.The length of this chromatographic column was 10 m,with an internal warp of 3 mm and a packing size of 1 mm,while the total separation units of the column reached 12,250.The most favorable conditions for the separation of nuclides were then obtained through optimizing the separation conditions of the device:Sample pH in the column=2,sample injection flow rate=5.698 mL/min,chromatographic column heating temperature=60℃.Separation experiments were also carried out for uranium,europium,and sodium ions in mixed solutions;uranium and sodium ions in water samples from the Ganjiang River;and uranium,sodium,and magnesium ions from seawater samples.The separation factors between the different nuclei were then calculated based on the experimental data,and a formula for the separation level was derived.The experimental results showed that the separation factor in the mixed solution of uranium and europium(1:1)was 1.088,while achieving the initial separation of uranium and europium theoretically required a 47-stage separation.Considering the separation factor of 1.50for the uranium and sodium ions in water samples from the Ganjiang River,achieving the initial separation of uranium and sodium ions would have theoretically required at least a 21-stage separation.Furthermore,for the seawater sample separation experiments,the separation factor of uranium and sodium ions was 1.2885;therefore,more than 28 stages of sample separation would be required to achieve uranium extraction from seawater.The novel pulsed liquid chromatography method proposed in this study was innovative in terms of uranium separation and enrichment,while expanding the possibilities of extracting uranium from seawater through chromatography.
基金supported by the National Natural Science Foundation of China(Nos.11675247,22176194).
文摘Direct collection of uranium from low uranium systems via adsorption remains challenging.Fibrous sorbent materials with amidoxime(AO)groups are promising adsorbents for uranium extraction from seawater.However,low AO adsorption group utilization remains an issue.We herein fabricated a branched structure containing AO groups on polypropylene/polyethylene spun-laced nonwoven(PP/PE SNW)fibers using grafting polymerization induced by radiation(RIGP)to improve AO utilization.The chemical structures,thermal properties,and surface morphologies of the raw and treated PP/PE SNW fibers were studied.The results show that an adsorptive functional layer with a branching structure was successfully anchored to the fiber surface.The adsorption properties were investigated using batch adsorption experiments in simulated seawater with an initial uranium concentration of 500μg·L^(−1)(pH 4,25℃).The maximum adsorption capacity of the adsorbent material was 137.3 mg·g^(−1)within 24 h;moreover,the uranyl removal reached 96%within 240 min.The adsorbent had an AO utilization rate of 1/3.5 and was stable over a pH range of 4–10,with good selectivity and reusability,demonstrating its potential for seawater uranium extraction.
基金financial support from the Talent Support Fund of Tsinghua University (No. 413405001)
文摘The radioactivity of uranium in radioactive coal bottom ash（CBA） may be a potential danger to the ambient environment and human health. Concerning the limited research on the distribution and mode of occurrence of uranium in CBA, we herein report our investigations into this topic using a number of techniques including a five-step Tessier sequential extraction, hydrogen fluoride（HF） leaching, Siroquant（Rietveld） quantification, magnetic separation, and electron probe microanalysis（EPMA）. The Tessier sequential extraction showed that the uranium in the residual and Fe–Mn oxide fractions was dominant（59.1%and 34.9%, respectively）. The former was mainly incorporated into aluminosilicates,retained with glass and cristobalite, whereas the latter was especially enriched in the magnetic fraction, of which about 50% was present with magnetite（Fe_3O_4） and the rest in other iron oxides. In addition, the uranium in the magnetic fraction was 2.6 times that in the non-magnetic fraction. The experimental findings in this work may be important for establishing an effective strategy to reduce radioactivity from CBA for the protection of our local environment.
文摘Amid the global energy transition and pursuit of ″dual-carbon″ goals, nuclear energy has attracted growing attention as a lowcarbon, high-efficiency power source. However, the limited terrestrial uranium reserves are only sufficient to sustain demand for a few decades.
基金supported by the National Key Research and Development Program of China (No. 2018YFC1900105)National Natural Science Foundation of China (Nos. U21A20290, 21876047)
文摘The rapid development of advanced techniques for selective and efficient U(Ⅵ) extraction from aqueous solutions is essential for addressing U(Ⅵ) environmental pollution and energy issues. Here, we share recent progress in U(Ⅵ) extraction from aqueous solutions, especially the most frequently applied techniques such as adsorption, catalysis(photocatalysis, piezocatalysis, and electrocatalysis), chemical deposition, and reduction by zero-valent metal particles. We attempt to elucidate the strategies and various mechanisms that contribute to the enhancement of selective U(Ⅵ) extraction. At the end of our review, we highlight the outlook, challenges, and prospects for the development of this field.
基金supported by the National Natural Science Foundation of China(U24B20195,U23A20105,U2341289,22341602).
文摘1 Introduction Nuclear energy is crucial not only for the fast development of industry but also for the achievement of CO_(2)emission peaking and carbon neutrality.The rapid increase of nuclear energy utilization in China requires a continuously nuclear fuel supply.However,the uranium resources on the land can only maintain about 70-100 years for nuclear power plants.There are~4.5×10^(10) t of uranium in the ocean.However,the uranium concentration in natural seawater is quite low(~3.3 ppb),and other competing cations affect uranium selective sorption obviously.More importantly,the bacteria and microorganisms in marine environments occupy the groups and active sites of materials,thereby decreasing the sorption ability[1].Uranium extraction from seawater is considered one of the“7 chemical separations and challenges to change the world”[2].
基金funded by National Natural Science Foundation of China(52273268)Qin Chuangyuan Team Construction Project of Shaanxi Science and Technology Department(2022KXJ-165)+2 种基金Shaanxi Province Technology Innovation Guidance Project(2023GXLH-079)Open Foundation of Key Laboratory of Auxiliary Chemistry and Technology for Chemical Industry,Ministry of Education,Shaanxi University of Science and Technology(KFKT2022-07)Shaanxi Province Outstanding Youth Science Foundation Project(2025JC-JCQN-053).
文摘Uranium plays a pivotal role in nuclear energy production, and extracting it from seawater offers a promising solution to alleviate shortages in land-based uranium resources. However, the marine environment with ultra-low uranium concentrations, high salinity, and microbial activity poses significant extraction challenges, compounded by selectivity and cost limitations in current methods. In the present investigation, an anti-biofouling amino oximefunctionalized collagen/sodium alginate aerogel(CF-AO/SA) was fabricated using leather waste-derived collagen. The dual cross-linked CF-AO/SA network, enhanced by Zn2+incorporation, showed improved structural stability and antibacterial properties, as well as high uranium adsorption capacity, selectivity, and reusability. It achieved 320.7 mg g-1in 14 ppm uranium solution and maintained 78.6% removal efficiency after five cycles. Additionally, the removal rate of uranium was 89% in simulated seawater. Field tests in Zhuhai's Jinwan District(113.35° E, 21.99° N) showed 5.16 mg g-1uranium adsorption and excellent mechanical strength after 30 days in seawater. Furthermore, the production cost of CF-AO/SA was estimated at $3.652 per kilogram, which is lower than other reported adsorbents. The newly developed bio-based aerogel beads have substantial potential for practical applications for uranium capture in seawater and provide a novel high-value utilization way for leather wastes.
基金supported by the National Natural Science Foundation of China(22371091,21975104,22150004,21731002 and 22101099)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(GZC20240598)+2 种基金the China Postdoctoral Science Foundation(2024M751118)the Guangdong Major Project of Basic and Applied Research(2019B030302009)the support from the Guangdong Basic and Applied Basic Research Foundation(2024A1515010897)。
文摘The development of novel metal-organic frameworks(MOFs)as solid adsorbents for rapid and efficient extraction of uranium from natural seawater is a long-term pursuit,yet remains challenging.In this work,we have prepared four two-dimensional(2D)vinylene-linked cyclic trinuclear units(CTUs)based MOFs.The metal nodes in the skeleton can be regulated,resulting in two Ag-CTU and two Cu-CTU-based MOFs with similar 2D hexagonal structures.These MOFs exhibit not only good stability in acid/base,γ-ray irradiation and natural seawater but also feature excellent anti-biofouling properties against five marine bacteria with inhibition rates as high as~99%.Interestingly,the alteration of Ag(I)to Cu(I)remarkably enhances the uranium sorption capacity due to the reduction of soluble U(VI)to insoluble U(IV)triggered by the chemical and photo-redox reaction of Cu-CTU.Due to the multiple functions,the Cu-CTU-based MOF delivers the best overall performance for uranium extraction from natural seawater with a high adsorption capacity of 7.96 mg g^(-1)and adsorption rate of~1.00 mg g^(-1)day^(-1),which is much higher than most of reported representative solid adsorbents.Our work paves a new way for rationally designing synergistic MOFs with superior performance for extracting uranium from natural seawater.
基金supported by internal funds from Tsinghua University.
文摘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,amidoxime-functionalized adsorbents based on low-cost polypropylene melt-blown nonwoven fabric(MBF)are produced by a simple,fast and also low-cost surface photografting technology,by which more than 80%of reagents can be saved and grafting time can be reduced to 3 min.The fabricated adsorbents retain their mechanical properties and exhibit excellent uranium adsorption properties,with a maximum uranium adsorption capacity of 400 mg g-1 when the monomer ratio of AN to AA is 8:2.Moreover,we showed that the adsorbents could be either reused or simply incinerated for uranium recovery.The photografting technology has great potential for low-cost,continuous industrial production of uranium-adsorbing material.
基金supported by the National Science Foundation of China(No.22422603 and 22266015).
文摘Seawater contains approximately 4.5 billion tons of dissolved uranium,making it a significant potential source of nuclear fuel.However,the low uranium concentration,interference from competing ions,and the complex marine environment pose major challenges to the economic feasibility of uranium extraction.Among various extractionmethods,adsorption is considered the most promising due to its low cost,simple operation,and strong adaptability tomarine conditions.Current research primarily focuses on developing high-performance adsorbent materials,including polymers,MXene,framework materials,and bio-based adsorbents.To optimize adsorbent performance,efforts are directed toward enhancing adsorption selectivity,increasing functional group utilization,improving adsorption kinetics,and strengthening environmental adaptability.Researchers have explored various strategies to achieve these goals,such as ion imprinting,functional group engineering,and the application of external energy fields(e.g.,light,electric fields)to enhance adsorption efficiency and uranium recovery.Although significant progress has been made in laboratory settings,real-world marine applications still face critical challenges,including biofouling resistance,large-scale engineering deployment,and efficient recovery.Future research efforts should focus on developing novel adsorbents,advancing external field-assisted extraction technologies,and optimizing large-scale engineering applications to enhance the practicality of seawater uranium extraction,ultimately making it a viable source of nuclear fuel.
基金National Natural Science Foundation of China(Nos.22465001,22105034,22202039, 22466003)Young Elite Scientists Sponsorship Program by JXAST(No.2024QT11)+2 种基金the Jiangxi Provincial Natural Science Foundation(Nos.20232BAB203042,20242BAB22002,20242BAB23023)the Academic and Technical Leaders of Major Disciplines in Jiangxi Province(No.20232BCJ23017)the Graduate Innovation Fund of East China University of Technology(No.DHYC-202420).
文摘Addressing the challenges of uranium extraction from seawater(UES)requires innovative strategies to overcome ultralow concentration(3.3 ppb)and thermodynamic limits.Herein,we propose a regioisomeric engineering strategy to design vinylene-linked covalent organic frameworks(COFs)for synergistic adsorption-photocatalytic UES.Two isomeric COFs,β-PTTN-AO andα-PNNB-AO,were synthesized by tuning the substitution positions of amidoxime(AO)groups on olefin bonds.Theβ-PTTN-AO isomer achieves a remarkable UES capacity of 12.74±0.21 mg·g^(-1)in nature seawater,surpassing itsα-positioned counterpart(8.9±0.18 mg·g^(-1))and outperforming most reported photocatalysts.Combined experiments and density functional theory(DFT)theoretical studies correlate regioisomeric configurations with electronic structure modulation and photocatalytic activity.Specifically,β-PTTN-AO enhanceπ-electron delocalization and strengthen built-in electric fields,promoting exciton dissociation,charge separation,and uranium reduction.This work establishes a molecular design paradigm for COF photocatalysts,advancing sustainable nuclear energy through structural isomerism.
基金supported by the National Natural Science Foundation of China (11275252)the Key Program of Strategically Advanced Science and Technology Project of the Chinese Academy of Sciences (XDA02040301)the Knowledge Innovation Program of Chinese Academy of Sciences
文摘An amidoxime-based ultra-high molecular weight polyethylene （UHMWPE） fibrous adsorbent was successfully prepared by T-irradiation-induced graft copolymerization of acrylonitrile （AN） and acrylic acid （AA）, followed by amidoximation. The grafting of AN and AA on the UHMWPE fiber and the amidoximation of the grafted fiber were confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The mechanical property of the original and modified UHMWPE fibers was compared by single-filament strength test. The adsorption property of the UHMWPE fibrous adsorbent was evaluated by adsorption test in uranyl nitrate solution and seawater. The surface of the modified UHMWPE fibers was covered by the grafting layer and became rough. The tensile strength of the amidoxime-based UHMWPE fibrous adsorbent was influenced by the absorbed dose and hydrochloric acid elution, but was independent of the grafting yield and amidoximation. The uranium adsorption amount of the amidoxime-based UHMWPE fibrous adsorbent after immersing in seawater for 42 days was 2.3 mg-U/g.
基金supported by the National Natural Science Foundation of China(Nos.12075066 and 21866007)the Innovation Project of Guangxi Graduate Education(No.YCBZ2022017).
文摘Photocatalytic uranium extraction from radioactive nuclear wastewater and seawater is critical for promoting the sustainable advancement of nuclear industry,but the complexity of real-world environments,particularly the occurrence of anoxic and oxygen-enriched states,presents significant challenges to effective uranium extraction.Here,a layered hollow core–shell structure of Bi_(2)O_(3)/g-C_(3)N_(4)Z-scheme heterojunction photocatalyst has been designed and successfully applied for photocatalytic uranium extraction in both aerobic and oxygen-free conditions,and the extraction efficiency of uranium can reach 98.4%and 99.0%,respectively.Moreover,the photocatalyst still has ultra-high extraction efficiency under the influence of pH,inorganic ions,and other factors.The exceptional capability for uranium extraction is on the one hand due to the distinctive hollow core–shell architecture,which furnishes an abundant quantity of active sites.On the other hand,benefiting from the suitable band gap structure brought by the construction of Z-scheme heterojunction,Bi_(2)O_(3)/g-C_(3)N_(4)exhibits current densities(1.00μA/cm^(2))that are 5.26 and 3.85 times greater than Bi_(2)O_(3)and g-C_(3)N_(4),respectively,and the directional migration mode of Z-scheme carriers significantly prolongs the lifetime of photogenerated charges(1.53 ns),which separately surpass the pure samples by factors of 5.10 and 3.19.Furthermore,the reaction mechanism and reaction process of photocatalytic uranium extraction are investigated in the presence and absence of oxygen,respectively.
基金supported by the National Natural Science Foundation of China(No.22301108)the Project Startup Foundation for Distinguished Scholars of Jiangsu University(No.4111310026).
文摘Porphyrinoid metal-organic frameworks(MOFs)with dual effective uranium uptake sites were synthesized through combined insitu and post-synthetic method.The MOF10@5 demonstrates the uptake amount of uranium reaches 1476 mg/g under visiblelight irradiation.The PN-MOF10@5 with dual uranyl uptake sites yields the amount of extracting uranyl of 1590 mg/g under visible-light irradiation.The density functional theory(DFT)calculations reveal strong interaction between uranyl and dual uranyl effective active sites.These MOFs demonstrate a powerful synthesis strategy for uranium extraction materials with dual effective active sites.
基金supported by the National Key R&D Program of China(No.2019YFA0706802)the National Natural Science Foundation of China(No.52002356 and U20A20141)+1 种基金China Postdoctoral Science Foundation(No.2023M731020)Project for Young Scientists in Basic Research(No.YSBR-039).
文摘Efficient and selective extraction of uranium(U(VI))from seawater is essential for sustainable nuclear power production.This study reports a novel adsorbent zeolitic imidazolate framework(ZIF)-67@SiO_(2)-A/polyacrylamide(PAM)which was synthesized by grafting the core–shell metal–organic frameworks(MOFs)-based nanostructures coated with the 3-aminopropyl triethoxysilane(APTES)functionalized SiO_(2)(SiO_(2)-A)onto PAM hydrogel.The SiO_(2) shell was grown on the surface of MOF,which improved the acid-base resistance of MOF.The introduction of ZIF-67@SiO_(2)-A enhances the specific surface area and adsorption efficiency of the PAM.The ZIF-67@SiO_(2)-A/PAM shows remarkable adsorption capacity,fast adsorption kinetics,and good reusability for uranium.It has excellent adsorption property(6.33 mg·g^(-1),30 d)in natural seawater.The X-ray photoelectron spectroscopy(XPS),Fourier transform infrared(FTIR),energy dispersive spectroscopy(EDS)mappings,and density functional theory reveal that the coordination by N and O in ZIF-67@SiO_(2)-A/PAM with uranium is the main mechanism of uranium adsorption.Thus,ZIF-67@SiO_(2)-A/PAM has great potential to capture uranium from natural seawater.
文摘The laser-induced optical fiber fluorimetry has been used for the first time to analyse the concentration of uranium(VI) in the kinetic studies on the extraction of uranium(VI) between 0.5 mol/L H_3PO_4 solution and HDEHP-cyclohexane system with Lewis cell. The effects of stirring speed, temper- ature and concentration of uranium(VI) and HDEHP on the rate of extraction were examined. These data show that the extraction rate of uranium(VI) in this system is controlled by the chemical reaction process at the interface. The rate equations and the rate constants of the forward and reverse ex- tractions were obtained. The mechanism of the extraction has been discussed.
文摘We study here the response of photonic hydrogels(PHs),made of photonic crystals of homogeneous silica particles in polyacrylamide hydrogels(SPHs),to the uranyl ions 22 UO_(2)^(2+) in aqueous solutions.It is found that the reflection spectra of the SPH show a peak due to the Bragg diffraction,which exhibits a blue shift in the presence of 22 UO_(2)^(2+).Upon exposure to the SPH,22 UO_(2)^(2+)gets adsorbed on the SPH and forms complex coordinate bonds with multiple ligands on the SPH,which causes shrinking of hydrogel and leads to the blue shift in the diffraction peak.The amount of the blue shift in the diffraction peak increases monotonically up to 22 UO_(2)^(2+)concentrations as high as 2300μM.The equilibration time for the shift in the Bragg peak upon exposure to 22 UO_(2)^(2+)is found to be~30 min.These results are in contrast to the earlier reports on photonic hydrogels of inhomogeneous microgel particles hydrogel(MPH),which shows the threshold 22 UO_(2)^(2+)concentration of~600μM,below which the diffraction peak exhibits a blue shift and a change to a red shift above it.The equilibration time for MPH is~300 min.The observed monotonic blue shift and the faster time response of the SPH to 22 UO_(2)^(2+)as compared to the MPH are explained in terms of homogeneous nature of silica particles in the SPH,against the porous and polymeric nature of microgels in the MPH.We also study the extraction of 22 UO_(2)^(2+)from aqueous solutions using the SPH.The extraction capacity estimated by the arsenazo-III analysis is found to be 112 mM/kg.
