Novel biocompatible N-rich AIE fluorescent probe for live cell imaging and visual onsite detection of uranium.

A sensitive and biocompatible N-rich probe for rapid visual uranium detection was constructed by grafting two trianiline groups to 2,6-bis(aminomethyl)pyridine. Possessing excellent aggregation-induced emission (AIE) property and the advantages to form multidentate chelate with U selectively, the probe has been applied successfully to visualize uranium in complex environmental water samples and living cells, demonstrating outstanding anti-interference ability against large equivalent of different ions over a wide effective pH range. A large linear range (1.0 × 10-7-9.0 × 10-7 mol/L) and low detection limit (72.6 nmol/L, 17.28 ppb) were achieved for the visual determination of uranium. The recognition mechanism, photophysical properties, analytical performance and cytotoxicity were systematically investigated, demonstrating high potential for fast risk assessment of uranium pollution in field and in vivo.

Modeling subsurface contaminant transport from a former open-pit uranium mine in fractured granites (La Ribière, France): Reducing uncertainties with geophysics.

The long-term management of tailings from former uranium (U) mines requires an in-depth understanding of the hydrogeological processes and water flow paths. In France, most of the legacy U mines are located in fractured crystalline (plutonic) rocks, where the intrinsic subsurface heterogeneity adds to the uncertainties about the former extraction and milling activities and the state of the mine when production was ceased. U ores were mainly processed by sulfuric acid leaching, leading to high-sulfate-content mill tailings now contained in several tailing storage facilities (TSFs). The La Ribière site, located in western central France, is a former open-pit and underground U mine, closed in 1992 and used to store mill tailings. This site is being used as a test case to establish a workflow in order to explain and predict water flow and subsurface contaminant transport. A conceptual model of water flow and sulfate transport, at the scale of the La Ribière watershed, is first developed based on available information and hydrogeochemical monitoring. Recent geophysical investigations allows refining this model. Electrical Resistivity Tomography (ERT) proves to be efficient at localizing the extent of the highly conductive sulfate plume inherited from the U-mill tailings, but also at imaging the weathering profile. Magnetic Resonance Sounding (MRS), despite the limited signal intensity due to the low porosity in crystalline rocks, gives some insight into the porosity values, the depth of the fractured layer and the location of the low-porosity ore-processing muds. Based on this conceptual model, a 3D flow and non-reactive transport model with the METIS code is developed and calibrated. This model allows predicting the evolution of the sulfate plume, but will also be used in future investigations, to build reactive transport models with simplified hydrogeology for U and other reactive contaminants.

Cinnamic Acid: A Low-Toxicity Natural Bidentate Ligand for Uranium Decorporation.

Uranium accumulation in the kidneys and bones following internal contamination results in severe damage, emphasizing the pressing need for the discovery of actinide decorporation agents with efficient removal of uranium and low toxicity. In this work, cinnamic acid (3-phenyl-2-propenoic acid, CD), a natural aromatic carboxylic acid, is investigated as a potential uranium decorporation ligand. CD demonstrates markedly lower cytotoxicity than that of diethylenetriaminepentaacetic acid (DTPA), an actinide decorporation agent approved by the FDA, and effectively removes approximately 44.5% of uranyl from NRK-52E cells. More importantly, the results of the prompt administration of the CD solution remove 48.2 and 27.3% of uranyl from the kidneys and femurs of mice, respectively. Assessments of serum renal function reveal the potential of CD to ameliorate uranyl-induced renal injury. Furthermore, the single crystal of CD and uranyl compound (C9H7O2)2·UO2 (denoted as UO2-CD) reveals the formation of uranyl dimers as secondary building units. Thermodynamic analysis of the solution shows that CD coordinates with uranyl to form a 2:1 molar ratio complex at a physiological pH of 7.4. Density functional theory (DFT) calculations further show that CD exhibits a significant 7-fold heightened affinity for uranyl binding in comparison to DTPA.

Enhancing radioprotection: A chitosan-based chelating polymer is a versatile radioprotective agent for prophylactic and therapeutic interventions against radionuclide contamination.

To mitigate the risk of radioactive isotope dissemination, the development of preventative and curative measures is of particular interest. For mass treatment, the developed solution must be easily administered, preferably orally, with effective, nontoxic decorporating properties against a wide range of radioactive isotopes. Currently, most orally administered chelation therapy products are quickly absorbed into the blood circulation, where chelation of the radioactive isotope is a race against time due to the short circulation half-life of the therapeutic. This report presents an alternative therapeutic approach by using a functionalized chitosan (chitosan@DOTAGA) with chelating properties that remains within the gastrointestinal tract and is eliminated in feces, that can protect against ingested radioactive isotopes. The polymer shows important in vitro chelation properties towards different metallic cations of importance, including (Cs(I), Ir(III), Th(IV), Tl(I), Sr(II), U(VI) and Co(II)), at different pH (from 1 to 7) representing the different environments in the gastrointestinal tract. An in vivo proof of concept is presented on a rodent model of uranium contamination following an oral administration of Chitosan@DOTAGA. The polymer partially prevents the accumulation of uranium within the kidneys (providing a protective effect) and completely prevents its uptake by the spleen.

Constructing amidoxime adsorption sites on the core-shell structured natural silk protein for uranium capture.

Amidoxime-based fiber adsorbents hold significant promise for uranium extraction. However, a notable issue is that these adsorbents primarily originate from synthetic polymer materials, which, aside from providing good mechanical support, have no other functions. In recent study, we shifted our focus to silk fiber (SF), a natural protein fiber known for its unique core-shell structure and rich amino acids. The shell layer, due to its abundant functional groups, makes it easily modifiable, while the core layer provides excellent mechanical strength. Leveraging these inherent properties, an amidoxime-based fiber adsorbent was developed. This adsorbent utilizes amino and carboxyl groups for enhanced performance synergistically. This method involves establishing uranium affinity sites on the outer sericin layer of SF via chemical initiation of graft polymerization (CIGP) and amidoximation (SF-g-PAO). The water absorption ratio of SF-g-PAO is as high as 601.16 % (DG = 97.17 %). Besides, SF-g-PAO demonstrates an exceptional adsorption capacity of 15.69 mg/g in simulated seawater, achieving a remarkable removal rate of uranyl ions at 95.06 %. It can withstand a minimum of five adsorption-elution cycles. Over a 4-week period in natural seawater, SF-g-PAO displayed an adsorption capacity of 4.95 mg/g. Furthermore, SF-g-PAO also exhibits impressive uranium removal efficiency in real nuclear wastewater, with a removal rate of 63 % in just 15 min and a final removal rate of 90 %. It is hoped that this SF-g-PAO, prepared through this straightforward method and characterized by the synergistic action of amino and carboxyl groups, can offer innovative insights into the development of uranium extraction adsorbents.

Fabrication of cellulose-collagen based biosorbent as eco-friendly scavengers for uranyl ions.

The aim of the present research is to fabricate a biosorbent using agricultural waste for removal of uranium from contaminated water i.e. "waste to wealth" approach. Cellulose extracted from wheat straw was mercerized and a novel semi-interpenetrating polymer network (semi-IPN) was fabricated through graft copolymerization of polyvinyl alcohol onto hybrid mercerized cellulose + collagen backbone. Response surface methodology was used for optimization of different reaction parameters as a function of % grafting (195.1 %) was carried out. Semi-IPN was found to possess higher thermal stability. Adsorption results revealed that the optimum parameters for the elimination of uranium using semi-IPN were: adsorbent dose = 0.15 g, pH = 6.0, contact time = 120 min and initial U (VI) concentration = 100 µg/L. The pseudo-second-order kinetic model gave the best description of the adsorption equilibrium data as the calculated qe value is nearest to the experimental qe for the different initial U(VI) concentrations. Adsorption experiments followed Langmuir isotherm with R2 = 0.999. Furthermore, recyclability and reusability studies showed that the adsorption efficiency of semi-IPN was 82 % after 5 cycles indicating the superior recycling execution of fabricated biosorbent. Thus, the fabricated ecofriendly device can be used effectively for the removal of uranium from contaminated wastewater sources.

Ion-imprinted macroporous polyethyleneimine incorporated chitosan/layered hydrotalcite foams for the selective biosorption of U(VI) ions.

In order to prevent uranium pollution and recovery uranium resources, it was necessary to find a highly efficient adsorbent for radioactive wastewater treatment. Herein, U(VI) imprinted polyethyleneimine (PEI) incorporated chitosan/layered hydrotalcite composite foam (IPCL) was synthesized by combining ion-imprinting and freeze-drying techniques. IPCL has a high amino/imino content and an ultralight macroporous structure, making it capable of efficiently adsorbing U(VI) and easy to separate; Especially after ion-imprinting, vacancies matching the size of uranyl ions were formed, significantly improving U(VI) selectivity. The adsorption isotherms and adsorption kinetics were in accordance with the Freundlich model and PSO model respectively, indicating that heterogeneous adsorption of U(VI) by the adsorbents. The adsorption capacity of IPCL-2 for U(VI) reached 278.8. mg/g (under the conditions of optimal pH 5.0, temperature of 298 K, contact time of 2 h, and adsorbent dosage of 0.2 g/L), which is almost double of that for the non-imprinted foam (PCL-2, 138.2 mg/g), indicating that IPCL-2 can intelligently recognize U(VI). The heterogeneous adsorption mechanism of U(VI) by IPCL-2 involves complexation, ion-exchange and isomorphic substitution. The adsorption of U(VI) by IPCL-2 is spontaneous and endothermic. IPCL-2 has excellent adsorption performance for U(VI), and is a promising adsorbent for radioactive pollution control.

Carboxymethyl cellulose and metal-organic frameworks immobilized into polyacrylamide hydrogel for ultrahigh efficient and selective adsorption U(VI) from seawater.

Metal-organic frameworks (MOF)-polymer hybrid hydrogel solves the processable forming of MOF powder and energy consumption of uranium extraction. However, the hybrid hydrogel by conventional synthesis methods inevitably lead to MOF agglomeration, poor filler-polymer interfacial compatibility and slowly adsorption. Herein, we designed that ZIF-67 was implanted into the carboxymethyl cellulose/polyacrylamide (CMC/PAM) by network-repairing strategy. The carboxyl and amino groups on the surface of CMC/PAM drive the uniform growth of ZIF-67 inside the CMC/PAM, which form an array of oriented and penetrating microchannels through coordination bonds. Our strategy eliminate the ZIF-67 agglomeration, increase the interfacial compatibility between MOF and polymer. The method also improve the free and fast diffusion of uranium in CMC/PAM/ZIF-67 hydrogel. According to the experimental, these enhancements synergistically enabled the CMC/PAM/ZIF-67 have a maximum adsorption capacity of 952 mg g-1. The adsorption process of CMC/PAM/ZIF-67 fits well with pseudo-second-order model and Langmuir isotherm. Meanwhile, the CMC/PAM/ZIF-67 maintain a high removal rate (87.3 %) and chemical stability even during ten adsorption-desorption cycles. It is worth noting that the adsorption amount of CMC/PAM/ZIF-67 in real seawater is 9.95 mg g-1 after 20 days, which is an ideal candidate adsorbent for uranium extraction from seawater.

A sodium alginate gel bead adsorbent doping with amidoxime-modified hydroxyapatite for the efficient adsorption of uranium.

In this work, the modified­sodium alginate gel beads were prepared by sol-gel method. Due to the presence of water channels in the sodium alginate gel bead, amidoxime groups and PO43- were exposed to the surface of the adsorbent to the maximum extent, resulting in the excellent adsorption capacity of modified­sodium alginate gel beads. The introduction of amidoxime-modified hydroxyapatite significantly improved the adsorption capacity and the adsorption rate of the gel beads. The adsorption capacity increased from 308.7 to 466.0 mg/g and the adsorption equilibrium time was shortened from 300 min to 120 min. The modified­sodium alginate gel bead possessed the advantages of short adsorption time, high adsorption efficiency and large adsorption capacity, which could be regarded as a potential adsorbent for uranium. Moreover, the uranium removal ability on the modified gel beads was mainly attributed to the Coulomb force between PO43- and uranium and the complexation between uranium and amidoxime groups. In summary, this work would provide a new idea for the modification and application of sodium alginate-based materials.

Effects of Fe(II) and humic acid on U(VI) mobilization onto oxidized carbon nanofibers derived from the pyrolysis of bacterial cellulose.

The effects of Fe(II) and humic acid on U(VI) immobilization onto oxidized carbon nanofibers (Ox-CNFs, pyrolysis of bacterial cellulose) were investigated by batch, spectroscopic and modeling techniques, with results suggesting that, Ox-CNFs exhibited fast adsorption rate (adsorption equilibrium within 3 h), high adsorption performance (maximum adsorption capacity of 208.4 mg/g), good recyclability (no notable change after five regenerations) in the presence of Fe(II) towards U(VI) from aqueous solutions (e.g., 40 % reduction and 10 % adsorption at pH 8.0), which was attributed to the various oxygen-containing functional groups, excellent chemical stability, large specific surface area and high redox effect. U(VI) adsorption increased with increasing pH from 2.0 to 5.0, then high-level plateau and remarkable decrease were observed at 5.0-6.0 and at pH > 6.0, respectively. According to FT-IR and XPS analysis, a negative correlation between U(VI) reduction and organic in the presence of Fe(II) implied that U(VI) reduction was driven by Fe(II) while inhibited by humic acid. The interaction mechanism of U(VI) on Ox-CNFs was demonstrated to be adsorption and ion exchange at low pH and reduction at high pH according to XPS and surface complexation modeling. These findings filled the knowledge gaps pertaining to the effect of Fe(II) on the transformation and fate of U(VI) in the actual environment. This carbon material with distinctive performance and unique topology offers a potential platform for actual application in environmental remediation.

Efficient removal of U(VI) from aqueous solution by CNN/UiO-66 under simulated sunlight irradiation: the synergy of adsorption and photocatalysis.

The reduction of soluble U(VI) to insoluble and less toxic U(IV) by photocatalysis is an effective method to control uranium contamination. The graphitic carbon nitride nanosheet (CNN)/UiO-66 composites (CNNU) were prepared by thermal polymerization and solvothermal methods for the removal of U(VI). The morphology, crystal structure and optical properties of composites were analyzed by SEM, XRD, BET, UV-DRS, PL and EIS. The results showed the introduction of UiO-66 increased the specific surface of CNN from 9.07 m2/g to 46.24 m2/g, and effectively suppressed the recombination of photogenerated electrons and holes and improved the photocatalytic activity. The U(VI) removal capacity by adsorption and photocatalysis of CNNU was reached 779.47 mg/g, which significantly higher than that of adsorption (478.38 mg/g). The adsorption process was found to conform to the pseudo-second-order kinetic model and the Langmuir isothermal model. Meanwhile, U(VI) adsorbed on the CNNU was reduced to U(IV) via e- and ·O2- generated in the photocatalytic process. Therefore, this outstanding performance of CNNU in U(VI) removal is attributed to the synergistic effect of adsorption and photocatalytic reduction.

Tungsten oxide encapsulated phosphate-rich porous alginate composites for efficient U(VI) capture: Insights into synthesis, adsorption kinetics and thermodynamics.

In this work, novel monoclinic tungsten oxide (WO3)-encapsulated phosphate-rich porous sodium alginate (PASA) microspherical hydrogel beads were prepared for efficient U(VI) capture. These macroporous and hollow beads were systematically characterized through XRD, FTIR, EDX-mapping, and SEM-EDS techniques. The O and P atoms in the PO and monoclinic WO3 offered inner-spherical complexation with U(VI). The in situ growth of WO3 played a significant role inside the phosphate-rich biopolymeric network to improve its chemical stability, specific surface area, adsorption capacity, and sorption rate. The phytic acid (PA) served for heteroatom doping and crosslinking. The encapsulated WO3 mass ratio was optimized in different composites, and WO3/PASA3 (the microspherical beads with a mass ratio of 30.0 % w/w) exhibited remarkable maximum sorption capacity qm (336.42 mg/g) computed through the best-fit Langmuir model (R2 ≈ 0.99) and rapid sorption equilibrium, teq (150 min). The isothermal sorption studies were conducted at different temperatures (298, 303, and 308 K) and thermodynamic parameters concluded that the process of U(VI) sorption using WO3/PASA3 is endothermic and feasible having ΔHo (8.19 kJ/mol), ΔGo (-20.75, -21.38, and - 21.86 kJ/mol) and proceeds with a minute increase in randomness ΔSo (0.09 kJ/mol.K). Tungsten oxide (WO3)-encapsulated phosphate-rich porous microspherical beads could be promising material for uranium removal.

Chelating Effect of Siderophore Desferrioxamine-B on Uranyl Biomineralization Mediated by Shewanella putrefaciens.

In contaminated water and soil, little is known about the role and mechanism of the biometabolic molecule siderophore desferrioxamine-B (DFO) in the biogeochemical cycle of uranium due to complicated coordination and reaction networks. Here, a joint experimental and quantum chemical investigation is carried out to probe the biomineralization of uranyl (UO22+, referred to as U(VI) hereafter) induced by Shewanella putrefaciens (abbreviated as S. putrefaciens) in the presence of DFO and Fe3+ ion. The results show that the production of mineralized solids {hydrogen-uranium mica [H2(UO2)2(PO4)2·8H2O]} via S. putrefaciens binding with UO22+ is inhibited by DFO, which can both chelate preferentially UO22+ to form a U(VI)-DFO complex in solution and seize it from U(VI)-biominerals upon solvation. However, with Fe3+ ion introduced, the strong specificity of DFO binding with Fe3+ causes re-emergence of biomineralization of UO22+ {bassetite [Fe(UO2)2(PO4)2·8(H2O)]} by S. putrefaciens, owing to competitive complexation between Fe3+ and UO22+ for DFO. As DFO possesses three hydroxamic functional groups, it forms hexadentate coordination with Fe3+ and UO22+ ions via these functional groups. The stability of the Fe3+-DFO complex is much higher than that of U(VI)-DFO, resulting in some DFO-released UO22+ to be remobilized by S. putrefaciens. Our finding not only adds to the understanding of the fate of toxic U(VI)-containing substances in the environment and biogeochemical cycles in the future but also suggests the promising potential of utilizing functionalized DFO ligands for uranium processing.

Experimental and computational evidence of U(VI)-OH-Si(OH)4 complexes under alkaline conditions: Implications for cement systems.

The complexation of uranyl hydroxides with orthosilicic acid was investigated by experimental and theoretical methods. Spectroluminescence titration was performed in a glovebox under argon atmosphere at pH 9.2, 10.5 and 11.5, with [U(VI)] = 10-6 and 5 × 10-6 mol kgw-1. The polymerization effects of silicic acid were minimized by ruling out samples with less than 90 % monomeric silicic acid present, identified via UV-Vis spectrometry using the molybdate blue method. Linear regression analysis based on time-resolved laser-induced fluorescence spectroscopy (TRLFS) results yielded the conditional stepwise formation constants of U(VI)-OH-Si(OH)4 complexes at 0.05 mol kgw-1 NaNO3. The main spectroscopic features - characteristic peak positions and decay-time - are reported for the first time for the UO2(OH)2SiO(OH)3- species observed at pH 9.2 and 10.5 and UO2(OH)2SiO2(OH)22- predominant at pH 11.5. Quantum chemical calculations successfully computed the theoretical luminescence spectrum of the complex UO2(OH)2SiO(OH)3- species, thus underpinning the proposed chemical model for weakly alkaline systems. The conditional stability constants were extrapolated to infinite dilution using the Davies equation, resulting in log10ß°(UO2(OH)2SiO(OH)3-) and log10ß°(UO2(OH)2SiO2(OH)22-). Implications for U(VI) speciation in the presence and absence of competing carbonate are discussed for silicate-rich environments expected in certain repository concepts for nuclear waste disposal.

Predominance of the alkaline earth(II) triscarbonatoactinyl(VI) complexes in different geochemical contexts: Review of existing data and estimation of potentially unidentified species.

From the available thermodynamic data in the literature, a review of the impact of the formation of complexes between triscarbonatoactinyl(VI) and alkaline earth(II) (Ae) is estimated under varying conditions. First, after analyzing the literature data and using the ascertained thermodynamic data available from the commissioned reviews from the Nuclear Energy Agency (Organization for the Economic Cooperation and Development) Thermochemical DataBank Project on actinides (An) U, Np, and Pu, and from recently determined AenUO2(CO3)3(4-2n)- thermodynamic functions, the formation of AenAnO2(CO3)3(4-2n)- complexes for Pu(VI) and Np(VI) are estimated using linear free energy relationships (LFERs). The data are in good agreement with the sole determination of AePuO2(CO3)32- from Jo et al. (Dalton Trans. 49, 11605), which gives a relative confidence in the LFERs, and allows the application to actual situations. From existing uranium data, first, the impact of the origin of the data on the calculated predominance is addressed under 0.1 M NaCl and atmospheric CO2(g); second, the influence of ionic strength and salinity on predominance is estimated; and finally, the influence of temperature up to 50 °C on the solubility of uraninite in a deep geological radioactive waste storage or disposal site is calculated. For neptunium and plutonium, the impact of the potential log10ß°(AenAnO2(CO3)3(4-2n)-) on Pourbaix diagrams of Pu and Np in Mg-Ca-CO3 media are estimated from Jo et al. (Dalton Trans. 49, 11605) and LFERs. Finally, the application to the speciation of Pu and Np in seawater is proposed.

One-step synthesis of phospho-rich, silica-enhanced chitosan aerogel for the efficient adsorption of uranium(VI).

In this study, an amorphous silica reinforced, phosphoric-crosslinked chitosan foam (P-CTS@SixOy) was prepared. The introduction of amorphous silica not only increased the affinity of the adsorbent for uranium, but also improved the stability of the material. The number of active sites of P-CTS@SixOy was increased by the introduction of phosphate groups. The material exhibited excellent uranium adsorption performance with the removal capacity and efficiency of 850.5 mg g-1 and 98.1 %, respectively. After regenerations, the morphology of P-CTS@SixOy still maintained, and the uranium adsorption efficiency remained above 90 %, manifesting the excellent cycle performance of P-CTS@SixOy. In the dynamic adsorption experiment, P-CTS@SixOy successfully concentrated the volume of uranium-containing solution, and exhibited excellent uranium adsorption performance. The analysis of kinetics, isotherms, and thermodynamics manifested that the uranium adsorption behavior of P-CTS@SixOy was a spontaneous, endothermic, monolayer chemical adsorption process. X-ray photoelectron spectroscopy, Scanning Electron Microscope, and Fourier Transform Infrared Spectrometer were used to characterized the P-CTS@SixOy before and after adsorption, which demonstrated that the main interaction mechanism between uranium and P-CTS@SixOy was the complexation. These studies indicated the huge application prospect of P-CTS@SixOy in the treatment of large-scale uranium-containing wastewater.

Microbial removal of uranyl from aqueous solution by Leifsonia sp. in the presence of different forms of iron oxides.

Immobilization of uranyl by indigenous microorganisms has been proposed as an economic and clean in-situ approach for removal of uranium, but the potential mechanisms of the process and the stability of precipitated uranium in the presence of widespread Fe(III) (hydr)oxides remain elusive. The potential of iron to serve as a reductant and/or an oxidant of uranium indicates that bioemediation strategies which mainly rely on the reduction of highly soluble U(VI) to poorly soluble U(IV) minerals to retard uranium transport in groundwater may be enhanced or hindered under different environmental conditions. This study purposes to determine the effect of ubiquitous Fe(III) (hydr)oxides (two-line ferrihydrite, hematite and goethite) on the removal of U(VI) by Leifsonia sp. isolated from an acidic tailings pond in China. The removal mechanism was elucidated via SEM-EDS, XPS and Mössbauer. The results show that the removal of U(VI) was retarded by Fe(III) (hydr)oxides when the initial concentration of U(VI) was 10 mg/L, pH was 6, temperature was 25 °C. Particularly, the retardatory effect of hematite on U(VI) removal was blindingly obvious. Also, it is worth noting that the U(VI) in the precipitate slow-released in the Fe(III) (hydrodr) oxide treatment groups, accompanied by an increase in Fe(II) concentration. SEM-EDS results demonstrated that the ferrihydrite converted to goethite may be the reason for U(VI) release in the process of 15 days culture. Mössbauer spectra fitting results further imply that the metastable iron oxides were transformed into stable Fe3O4 state. XPS measurements results showed that uranium product is most likely a mixture of Iron-U(IV) and Iron-U(VI), which indicated that the hexavalent uranium was converted into tetravalent uranium. These observations imply that the stability of the uranium in groundwater may be impacted on the prevailing environmental conditions, especially the solid-phase Fe(III) (hydr)oxide in groundwater or sediment.

Elimination of uranium pollution from coastal nuclear power plant by marine microorganisms: Capability and mechanism.

Uranium is one of the sensitive radionuclides in the wastewater of nuclear powers. Due to the fact that nuclear powers are mainly located in coastal areas, the elimination of uranium (U(VI)) pollution from coastal nuclear power is ultimately rely on marine microorganisms. The fixing of U(VI) on V. alginolyticus surface or converting it into sediments is an effective elimination strategy for U(VI) pollution. In this work, typical marine microorganism V. alginolyticus was used to evaluate the elimination of U(VI) pollution by marine microorganisms. Effects of solution conditions (such as pH, temperature, and bacterium concentrations) on the physicochemical properties and elimination capabilities of V. alginolyticus were studied in detail. FT-IR, XPS and XRD results reveal that COOH, NH2, OH and PO4 on V. alginolyticus were main functional groups for U(VI) elimination and formed (UO2)3(PO4)2·H2O. The elimination of U(VI) by V. alginolyticus includes two stages of adsorption and biomineralization. The theoretical maximum adsorption capacity (Cs,max) of V. alginolyticus for U(VI) can reach up to 133 mg/g at pH 5 and 298 K, and the process reached equilibrium in 3 h. Results show that V. alginolyticus play important role in the elimination of U(VI) pollution in seawater.

High mechanical property and hydrophilic electrospun poly amidoxime/poly acrylonitrile composite nanofibrous mats for extraction uranium from seawater.

Seawater reserves about 4.5 billion tons of uranium, if properly extracted, could be a sustainable green energy resource for hundreds of years, alternating its limited terrestrial ore and reducing the CO2 emitted from fossil fuels. The current seawater uranium adsorbents suffer neither economically viable nor adsorption efficiency, requiring more development to harvest satisfactorily uranium from seawater. Amidoxime-based fibrous adsorbents are the most promising adsorbents of seawater uranium due to abundant chelating sites. However, they suffer from severe shrinkage and stiffness once they dry, losing porous architecture and mechanical properties. Herein, an economical and scalable two-nozzle electrospinning technology was applied to produce poly amidoxime nanofibers (PAO NFs) supported by Poly acrylonitrile nanofibers (PAN NFs) as composite PAO/PAN nanofibrous mats with high structure stability. These PAO/PAN mats, with rapid wettability and excellent mechanical strength, show promising uranium adsorption capacities of 369.8 mg/g at seawater pH level, much higher than PAO and PAN NFs. The uranium adsorption capacity of the PAO/PAN mat reached 5.16 mg/g after 7 days of circulating (10 ppm uranium) spiked natural seawater. Importantly, the composite mat maintained its fibrous structure after five adsorption-desorption cycles with more than 80 % of its adsorption capacity, confirming its recyclability and stability. Therefore, the composite PAO/PAN mat fulfills the basic requirements for effectively and economically trapping uranium from seawater, which could be a matrix for further development.

Plant polyphenol surfactant construction with strong surface activity and chelation properties as efficient decontamination of UO22+ on cotton fabric.

Chemically synthesized surfactants have promising applications in the treatment of uranium, however, their hazardous environmental effects, non-biodegradability, and numerous drawbacks prevent them from being widely used in practice. Herein, we successfully synthesized a green chelating and foaming integrated surfactant (BTBS) by Mannich reaction and acylation of bayberry tannin for the effective removal of UO22+ from aqueous environments or solid surfaces. The as-prepared surfactant was systematically characterized by FT-IR, showing that the hydrophobic groups were successfully grafted onto tannin. The modified material showed better foaming and emulsifying properties, which proved this method could improve the amphiphilicity of tannin. Moreover, for the first time, a foam fractionation method in conjunction with a tannin-based surfactant was applied for UO22+ removal from water. This surfactant was used as a co-surfactant and could readily remove 90 % of UO22+ (20 mg L-1) from water. The removal of UO22+ could be completed in a short time (30 min), and the maximum adsorption capacity was determined as 175.9 mg g-1. This surfactant can also be used for efficient decontamination of uranium-contaminated cotton cloth with a high removal rate of 94.55 %. In addition, the mechanism studies show that the adsorption of BTBS for UO22+ can be mainly attributed to a chelating mechanism between UO22+ and the adjacent phenolic hydroxyls. The novel biomass-derived BTBS with advantages such as high capture capacity, environmental friendliness, and cost-effectiveness suggests that it plays an important role in the remediation of radionuclide pollution.