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γ-raysand pulse radiolysis of aqueous solutions of Ni2+ionsin the presence of polyacrylate (PA–) and 2-propanolleads to the formation of metastable species absorbingat 540 nm that are ascribed to “pink” oligomeric clustersof a few nickel atoms only. The molar absorption coefficient is evaluatedas ε540 nm= 3300 ± 300 L mol–1cm–1per Ni0atom. The successive stepsfrom the reduction of Ni2+into Ni+ions tothe formation of the pink clusters at 540 nm under conditions of complexationby PA–are investigated by pulse radiolysis. Theyield of the formation of pink clusters increases markedly with theirradiation dose rate, demonstrating the occurrence of the disproportionationof the [Ni+, PA–] complex after a singleelectron pulse. The reduction and nucleation mechanisms, includingrate constants, in competition with the back oxidation by protons,particularly at low dose rate, are discussed. [ABSTRACT FROM AUTHOR]

The oxidation processes of the radiation-generated, three-electron-bonded intermediates AcMet 2 [S∴S] + and AcMet [S∴Br] were investigated by pulse radiolysis via their reactions with tryptophan (TrpH). These intermediates were derived from N-acetyl-methionine amide ( N-AcMetNH 2) and N-acetyl-methionine methyl ester ( N-AcMetOMe). The bimolecular rate constant k of the reaction between each intermediate and l-tryptophan (TrpH) was measured. For N-AcMetNH 2, k for the reaction of AcMet 2 [S∴S] + with TrpH were 3.4 × 10 8 and 2.2 × 10 8 dm 3 mol −1 s −1 at pH = 1 and 4.5, respectively. For N-AcMetOMe, k for the reaction of AcMet 2 [S∴S] + with TrpH were 4.0 × 10 8 and 2.8 × 10 8 dm 3 mol −1 s −1 at pH 1 and 4.5, respectively. The rate constants for the intermolecular transformation of Met [S∴Br] into TrpH + or Trp were also estimated. For N-AcMetNH 2, k for the reaction of AcMet 2 [S∴Br] with TrpH were 2.6 × 10 8 and 3.3 × 10 8 dm 3 mol −1 s −1 at pH 1 and 4.5, respectively. Related mechanisms were discussed. [ABSTRACT FROM AUTHOR]

The flavonolignans (silybin and analogues) are important natural compounds with multiple biological activities operating at various cell levels. Many of these effects are connected with their radical scavenging activities. In the present study, free-radical scavenging and antioxidant activities of four natural flavonoids, namely silybin, naringenin, naringin, and hesperetin, have been studied using nanosecond pulse radiolysis techniques. The kinetics and mechanisms of the reactions of silybin and analogues with various oxidizing radicals (such as •OH,N3•, CCl3OO•, SO4•−) have been investigated. Furthermore, the transient species has been assigned and radical scavenging rate constants have also been measured. Moreover, the structure-activity relationships between chemical structures of the flavonoids and their radical scavenging activities are further analayzed by theoretical calculation. Combined our previous observation of the fast reparation of DNA damage and efficient DNA protection against radiation damage in vitro, it can be confirmed that test flavonoids are promising molecules to be used for their potential antioxidant properties. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 590-597, 2011 [ABSTRACT FROM AUTHOR]

The absorption spectra of Br2•̵ and Br3̵ in aqueous solutions are investigated by pulse radiolysis techniques from room temperature to 380 and 350 °C, respectively. Br2•̵ can be observed even in supercritical conditions, showing that this species could be used as a probe in pulse radiolysis at high temperature and even under supercritical conditions. The weak temperature effect on the absorption spectra of Br2•̵ and Br3̵ is because, in these two systems, the transition occurs between two valence states; for example, for Br2̵ we have 2Σu→2Σg transition. These valence transitions involve no difiuse final state. However, the absorption band of Br̵ undergoes an important red shift to longer wavelengths. We performed classical dynamics of hydrated Br̵ system at 20 and 300 °C under pressure of 25 MPa. The radial distribution functions (rdfs) show that the strong temperature increase (from 20 to 300 °C) does not change the radius of the solvent first shell. On the other hand, it shifts dramatically (by 1 Å) the second maximum of the Br-- O rdf and introduces much disorder. This shows that the first water shell is strongly bound to the anion whatever the temperature. The first two water shells form a cavity of a roughly spherical shape around the anion. By TDDFT method, we calculated the absorption spectra of hydrated Br̵ at two temperatures and we compared the results with the experimental data. [ABSTRACT FROM AUTHOR]

Abstract: The absorption spectra of solvated electrons in pentanol, hexanol and octanol are measured from 22 to 200, 22 to 175 and 50 to150°C, respectively, at a fixed pressure of 15MPa, using nanosecond pulse radiolysis technique. The results show that the peak positions of the absorption spectra have a red-shift (shift to longer wavelengths) as temperature increases, similar to water and other alcohols. Including the above mentioned data, a compilation of currently available experimental data on the energy of absorption maximum (E max) of solvated electrons changed with temperature in monohydric alcohols, diols and triol is presented. E max of solvated electron is larger in those alcohols that have more OH groups at all the temperatures. The molecular structure effect, including OH numbers, OH position and carbon chain length, is investigated. For the primary alcohols with same OH group number and position, the temperature coefficient increases with increase in chain length. For the alcohols with same chain length and OH numbers, temperature coefficient is larger for the symmetric alcohols than the asymmetric ones. [ABSTRACT FROM AUTHOR]

Silybin (extracted from Silybum marianum) is the major active constituent of silymarin which possesses a wide range of medicinal properties. These properties may be, in part, due to the potent scavenging capacity of oxidizing free radicals. In this context, scavenging radicals (hydroxyl, azide, dibromide anion radicals, nitrite, carbonate, etc.) of silybin have been studied to understand the mechanistic aspects of its action against free radicals. The transients produced in these reactions have been assigned and the rate constants have been measured by pulse radiolysis techniques. Reduction potential determined both by cyclic voltammetry gave a value 0.62±0.02 V vs NHE at pH 9. Quantum chemical calculations have been performed to further confirm the different activities of individual hydroxyl groups with the difference of heat of formation. Moreover, silybin also protected plasmid pUC18 DNA from soft X-ray radiation which induced strand breaks. These results are expected to be helpful for a better understanding of the anti-oxidative properties of silybin. [ABSTRACT FROM AUTHOR]

Abstract: The absorption spectra of the hydrated electron in concentrated LiCl, LiClO4, Li2SO4, MgCl2 and Mg(ClO4)2 deuterated water solutions were measured by pulse radiolysis techniques from room temperature to 300°C at a constant pressure of 25MPa. With increasing temperature, the absorption band of the solvated electron for all solutions shifts to larger wavelengths. Whatever the temperature, shifts to shorter wavelengths of the absorption spectrum were observed as salt effects. The results on the shape and broadening of the absorption spectrum are discussed. [Copyright &y& Elsevier]

Abstract: In order to study radiation-induced fast phenomena, a new pulse radiolysis system with higher time resolution based on pulse-and-probe method was developed and utilized for practical work. A few picosecond electron beam generated from a linear accelerator, in which a laser photocathode RF-gun is introduced, was synchronized with a femtosecond laser pulse which is employed as the analyzing light. The synchronization precision between them was suppressed within 1.6ps (rms). Converting the fundamental laser into white light continuum or optical parametric amplification allows to measure in the wide wavelength from visible to infrared region. [Copyright &y& Elsevier]

Abstract: The reactions between edaravone and various one-electron oxidants such as OH, , , and , have been studied by pulse radiolysis techniques. The transient species produced by the reaction of edaravone with OH radical shows an absorption band with λ max =320nm, while the oxidation by , , and CCl3OO results in an absorption band with λ max =345nm. Different from the previous reports, the main transient species by the reaction of edaravone with OH radical in the absence of O2 is attributed to OH-adducts. At neutral condition (pH 7), the rate constants of edaravone reacting with OH, , , CCl3OO , and are estimated to be 8.5×109, 5.8×109, 6×108, 5.0×108 and 2.4×109 dm3 mol−1 s−1, respectively. From the pH dependence on the formation of electron adducts and on the rate constant of edaravone with hydrated electron, the pK a of edaravone is estimated to be 6.9±0.1. [Copyright &y& Elsevier]

Abstract: The yield of the hydrated electron in the picosecond time range has been re-evaluated with an ultrafast pulse radiolysis system using a laser photocathode RF-gun in combination with a conventional one, and a value of 4.1±0.2 per 100eV of absorbed energy at 20ps was derived. This is consistent with recent experimental results using a time correlation method [Bartels et al., J. Phys. Chem. A 104, 1686-1691 (2000)] and with Monte-Carlo calculations [Muroya et al., Can. J. Chem. 80 1367-1374 (2002)]. [Copyright &y& Elsevier]

[Display omitted] • A novel GCM aerogel was prepared by directional freeze casting assisted self-assembly. • Similar to a turbine with multiple 'blades.' • A lamellar structure arranged vertically and radially. • Excellent photothermal conversion performance, high selectivity and uranium adsorption capacity. • Efficiently separate and extract uranium from wastewater by the one-piece chromatographic column. Developing efficient uranium adsorbent remains a considerable challenge owing to the complexity of seawater and wastewater systems. Herein, a novel graphene oxide (GO)/chitosan (CS)/2-methacryloyloxyethyl phosphorylcholine (MPC) (GCM) aerogel, similar to a turbine with multiple 'blades' in appearance, was prepared for separating and extracting uranium. The highly vertically aligned lamellar structure with microchannels provides sufficient movement space for uranium, and the introduction of GO and MPC endows GCM aerogel with excellent photothermal conversion performance, strong uranium adsorption selectivity and biofouling resistance activity. GCM aerogel possessed an adhesion resistance rate of up to 99 % against marine bacteria, and its saturation adsorption capacity of uranium reached 1912 mg/g. It also exhibited good uranium selective adsorption capacity in natural seawater owing to its high adsorption capacity, remarkable selectivity, and outstanding biofouling resistance activity. Additionally, the one-piece GCM aerogel column served as an effective column separation material to maximize the photothermal conversion characteristics. The adsorption capacity and adsorption rate of GCM aerogel column for uranium were significantly enhanced and the recovery rate of uranium from simulated uranium-containing wastewater reached 95.3 % under simulated sunlight irradiation. This study offers a novel strategy for separating and extracting uranium from seawater and wastewater. [ABSTRACT FROM AUTHOR]

Highlights Fluorine rubber (FKM) stands as a pivotal sealing material extensively employed in aerospace and nuclear industries. However, its efficacy will be seriously affected by ionizing radiation. Enhancing its radiation resistance becomes imperative to uphold the stability and safety of associated equipment. This study introduced hexagonal boron nitride (h‐BN) into the FKM as radioprotective fillers through mechanical blending. The interfacial interaction between matrix and h‐BN, the mechanical performances, thermal properties, and radiation stability of composites were systematically examined. Noteworthy findings highlight the presence of robust interaction forces between h‐BN and the matrix, leading to increased crosslink density and improved mechanical properties. The tensile strength of composite with 10 phr fillers (BN/FKM‐10) increased by 30% compared to that of pure FKM. Simultaneously, the introduction of h‐BN greatly enhanced thermal conductivity and radiation stability. The absorbed dose required to achieve a 50% reduction in elongation at break of BN/FKM‐10 surpassed that of FKM by 1.69 times. These results underscore the potential of incorporating h‐BN to simultaneously enhance the mechanical performance, thermal property, and radiation resistance of fluorine rubber. The chemical interaction force between h‐BN and FKM was confirmed. FKM composites tensile strength was enhanced by h‐BN as an additive crosslinker. The incorporation of h‐BN improves FKM composites thermal conductivity. The radiation resistance of FKM composites has been improved with h‐BN. [ABSTRACT FROM AUTHOR]

The radiolytic behaviors of aqueous ammonia solutions under γ-ray irradiation were investigated, focusing on several factors, including initial ammonia concentration, absorbed dose, and H3BO3 concentration. The main species including ammonia, H2O2, nitrogen oxides, and H2, were quantitatively analyzed. The results revealed the significant influence of the initial ammonia concentration on the radiolytic behavior of the aqueous ammonia solution. The existence of ammonia in the solution exhibited suppression of the concentrations of H2O2 and O2. Furthermore, the radiolysis of aerated aqueous ammonia solution led to the formation of nitrogen oxides (NO2− and NO3−). This process was driven by multiple oxidation reactions, in which O2 and ·OH played crucial roles. Interestingly, the addition of H3BO3 provided protection to ammonia during γ irradiation, while the concentration of H2O2 was increased. [ABSTRACT FROM AUTHOR]

In this work, the effects of the tungsten (W) converter and molybdenum target thickness on the 99Mo yield in the production of 99Mo via 100Mo(γ, n)99Mo photonuclear reaction were studied. The FLUKA program was applied to simulate the optimal size of the targets for the production of 99Mo under 50 MeV electron conditions, where the thicknesses of the W and Mo targets were 0.3 and 1.4 cm, respectively. The relative error between the calculation and the experimental results was less than 8%. The process of irradiating natural (natMo) and enriched (100Mo) molybdenum targets using electrons with a 1 mA average beam current was further simulated. The specific activity of enriched 100Mo is nearly ten times higher than that of natMo. The use of 100Mo targets also produces fewer radioactive impurities. This study provides a guidance on the size of W conversion and molybdenum targets, as well as the selection of molybdenum species, when producing 99Mo via photonuclear reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Three amidoxime adsorbents with different chain conformations were constructed via tert -butyl hydroperoxide-initiated surface graft polymerization. • Conformational effect is a key factor affecting uranium adsorption capacity. • The linear structure of P-E-PAO had the largest adsorption capacity. • The multi-arm structure of P-E-PMGO was most affected by pH and ionic strength. • The rigid structure of P-E-PEBO had the best selectivity. The amidoxime group has received widespread attention owing to its high affinity for uranium. Since this property was discovered, various amidoxime-based adsorbents have been developed for uranium adsorption. However, the effect of chain conformation on the uranium adsorption performance (in terms of adsorption capacity, stability, selectivity, etc.) of amidoxime adsorbents has rarely been studied. Herein, three amidoxime-based adsorbents with different chain conformations (linear, multi-armed, and rigid) were constructed via tert -butyl hydroperoxide-initiated surface graft polymerization by incorporating different monomer structures. Adsorption experiments revealed that the linear structure of P-E-PAO exhibited the highest adsorption capacity owing to the highest monomer-grafting ratio; the multi-arm structure of P-E-PMGO was affected by pH and ionic strength because of the most cyclic imide dioxime structure; and the rigid structure of P-E-PEBO showed the highest selectivity owing to the most open-chain amidoxime structure. These findings are expected to have strong implications in the optimization of adsorption material designs. [ABSTRACT FROM AUTHOR]

• PDA from self-aggregation of dopamine successfully wrap the surface of CeO 2. • PDA significantly improved the compatibility between SR and CeO 2. • Both CeO 2 and PDA@CeO 2 can keep the irradiated SR's mechanical properties. • Both CeO 2 and PDA@CeO 2 decreased the radiation induced crosslinking of SR. • The mechanism of PDA@CeO 2 reducing the radiation damage of SR was clarified. With the widespread use of nuclear science and technology, slowing down the aging of polymers in a radiation environment has become a matter of great concern. In this work, cerium dioxide (CeO 2) and CeO 2 encapsulated with dopamine (PDA@CeO 2) were selected as special fillers to prepare the silicone rubber (SR) composites, and their radiation resistance were investigated by comparing the mechanical properties and thermal performance before and after irradiation. The interfacial bridge formed by PDA results in a greater elongation at break for PDA@CeO 2 /SR5.0 (770.0 ± 33.6 %) than for CeO 2 /SR (686.0 ± 15.0 %). After irradiation with γ-rays, the retention of elongation at break of both CeO 2 /SR0.1 and PDA@CeO 2 /SR0.1 were larger than SR. Furthermore, PDA@CeO 2 /SR0.1 showed an impressive retention of 90.5 ± 2.7 % of the tensile strength retention after exposure to an absorbed dose of 200 kGy. The disparity in crosslink density prior to and following irradiation indicated that both CeO 2 and PDA@CeO 2 were efficacious in reducing radiation crosslinking within the SR. An electron paramagnetic resonance spectrometer and an ultraviolet lamp (UV-EPR) were used to observe in real time the free radical scavenging ability of CeO 2 and PDA@CeO 2 inside the SR. These results indicated that CeO 2 and PDA@CeO 2 was expected to prevent further chain reactions in silicone rubber by scavenging free radicals generated in SR, thus improving the radiation resistance of SR. [ABSTRACT FROM AUTHOR]

[Display omitted] • The ionic liquid [HOEmim][NTf 2 ] can strengthen the extraction performance of TBP for Co2+. • The extraction efficiency of TBP/kerosene/[HOEmim][NTf 2 ] system for Co2+ is up to 99.6 %. • DFT calculations and FT-IR analysis indicate that Co2+ mainly binds to P=O in TBP. • A theoretical basis for removing Co2+ from waste water based on ionic liquids was laid. • ABSTRACT In order to achieve effective removal of radioactive Co(II) from the primary circuit wastewater of nuclear power plants and promote the safe use of nuclear energy, an efficient and eco-friendly method using ionic liquid as a co-extractant was proposed. The effects of ionic liquids 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C 2 mim][NTf 2 ]) or 1-(2-hydroxyethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([HOEmim][NTf 2 ]) as co-extractants on the extraction of Co(II) using tributyl phosphate (TBP) as an extractant were investigated in this work. The results reveal that the optimal extraction conditions for Co(II) are as follows: V TBP : V kerosene : V [HOEmim][NTf2] = 18:1:1, R(O/A) = 1, pH=4. Under these conditions, the extraction efficiency of Co(II) (E Co) reaches 99.6 %, with a distribution ratio (D Co) of 257. Notably, a single TBP or ionic liquid exhibits minimal ability to extract Co2+, while adding only 5 % (v/v) ionic liquid based on TBP/kerosene system can increase D Co by 104 times. The slope method and FT-IR analysis demonstrate that the TBP/kerosene/[HOEmim][NTf 2 ]/ system extracted Co2+ by a cation exchange mechanism. In addition, density functional theory (DFT) calculations were employed to explain the influence of different ionic liquid systems on the E Co , and further elucidate the extraction mechanism of Co2+. The striping results indicate that 92.2 % of Co2+ is stripped with 1.0 mol L−1 HNO 3. The extraction efficiency of Co(II) from the TBP/kerosene/[HOEmim][NTf 2 ] system remained at 98 % after 6 cycles. Therefore, the extraction system exhibits great practical potential in removing Co(II) from contaminated water. This work not only proposes an extraction system with excellent reusability and stability, but also lays a theoretical foundation for the ionic liquid-based cobalt extraction process. [ABSTRACT FROM AUTHOR]

A mathematical model of co-decontamination process (1A) containing U(VI), Pu(IV), Zr(IV), and Ru(III) was developed with a high-performance Iteration of Extraction Equilibrium (ITEE) algorithm. ITEE algorithm not only guarantees the positive solution set but also possesses better computational efficiency than L-BFGS-B and fsolve algorithms. This model was used to study the effects of the HNO3 concentration and the location of the feed stage on the extraction and decontamination efficiencies. The results show HNO3 is beneficial to the extraction of U, Pu, and Zr. More extraction stages boost the extraction of U and Pu into the organic phase. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effect of the structure for three ligands was systematically re-visited. • Complexation properties of Np and Pu complexes were explored by DFT calculations. • QTAIM analysis indicated that M O (P O) bonds were ionic characteristics. • The work laid theoretical basis for synthesis of neutral ligand to recover Np and Pu. Organophosphorus ligands such as TBP, TiAP, and DMHMP have exhibited excellent performance in recovering actinides from spent fuel. In this work, the molecular geometries and properties of TBP, TiAP and DMHMP were investigated using density functional theory calculations. Furthermore, the extraction mechanism of ligands for actinides (Np(Ⅵ), Pu(Ⅳ)) was further elucidated by simulating the microstructures and extraction reactions of metal–ligand complexes. The results demonstrate that the complexation ability of the three ligands on actinide cations (NpO 2 2+ and Pu4+) follows the order of DMHMP > TiAP > TBP. The electrostatic potential (ESP) analysis indicates that the nucleophilic ability of DMHMP is stronger than that of the other two ligands. The frontier molecular orbital analysis of the three ligands represents that DMHMP has the highest HOMO energy, suggesting that it has the strongest electron-donating capability and is more likely to bond with metal ions. The values of Wiberg bond indices (WBI) suggest that the M O bonds in DMHMP complexes have more covalency. According to the QTAIM analysis, the interactions between actinide cations and the ligands are predominantly ionic in nature. The molecular orbital analysis of the complexes shows that the M(NO 3) n ·2DMHMP (M NpO 2 2+ and Pu4+) complexes are more stable, which is supported by thermodynamic energy analysis. This work has clarified the complexing properties of actinide cations with three ligands, shedding light on the extraction mechanisms of organophosphorus ligands for actinide cations. It is anticipated to lay the theoretical foundation for the efficient recovery of critical actinide elements in spent fuel reprocessing, which will also provide innovative approaches for the design and development of related separation processes. [ABSTRACT FROM AUTHOR]

Abstract: Two histidine-containing natural dipeptides, carnosine and anserine (β-alanyl-1-methyl-l-histidine), have been examined for their antioxidant and radioprotective abilities. Pulse radiolysis studies indicated the antioxidative properties of carnosine and anserine aqueous solutions at different pH. The rate constants for the reaction OH radical with carnosine at neutral pH were determined to be 5.3×109 M−1 s−1 at 300nm, and 4.1×109 M−1 s−1 at 400nm, respectively. Carnosine and anserine also protected plasmid pUC18 DNA from X-ray radiation-induced strand breaks as evidenced from the studies by agarose gel electrophoresis. Carnosine showed higher protective efficiency under the experimental conditions. Our data demonstrated that carnosine and anserine may play an important role in the maintenance of the antioxidant system. [Copyright &y& Elsevier]

Abstract: In the present work, laser photolysis techniques have been used to study the transient species of silybin (abbreviated as SLB) in ethanol solutions. It has been demonstrated that the exposure of silybin to 248nm excimer laser gives rise to monophotonic ionization with a high quantum yield. The transient species have been identified, and a series of related kinetics parameters have also been obtained. For the sake of comparison, we approached the problem using another way to reduce silybin, i.e. attack of solvated electrons, esol −, produced in pulse radiolysis. The rate constant for reaction of esol − was determined to be 3.8×109 dm3 mol−1 s−1 at 720nm, which is consistent with 4.6×109 dm3 mol−1 s−1, obtained by laser photolysis. [Copyright &y& Elsevier]

Abstract: Measurements of primary g-values (at ∼10−7 s after the initial ionizing event) of , OH and H2O2 were extended to the very high linear energy transfer (LET) region (∼700eV/nm) near the Bragg peak. Heavy ions (4He2+, 12C6+, 20Ne10+, 28Si14+, 40Ar18+ and 56Fe26+) of energies up to 28GeV were provided by the Heavy Ion Medical Accelerator in Chiba (HIMAC) of the National Institute of Radiological Sciences (NIRS) in Chiba, Japan. Energies of the ions were decreased down to about 10MeV/u for 4He2+ using an energy absorber made of polymethylmethacrylate (PMMA) plates in order to vary the LET values. Beam was visualized after passing through the energy absorber using agarose gel of aqueous solution containing methyl viologen and sodium formate in order to determine how long ions can penetrate into water. Based on the information of the penetration depth of ions in samples, much attention was paid to dose correction and LET evaluation. The obtained data were plotted as a function of (Z eff/β)2 also instead of LET in order to discuss effects of physical track structures on product yields, resulted in better universality. [Copyright &y& Elsevier]

Abstract: Water radiolysis has been investigated with heavy ions having energies up to 28GeV provided from the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS). Beams of 4He2+, 12C6+, 20Ne10+, 28Si14+, 40Ar18+ and 56Fe26+ with respective energies of 150, 400, 400, 490, 500 and 500MeV/u corresponding LET values of 2.2, 13, 30, 54, 92 and 183eV/nm, respectively, were taken for the irradiation. The LET changes in sample solutions can be neglected due to their high energies for the irradiation of 1-cm cells. Primary g values have been determined for three important products, hydrated electron (e− aq), hydroxyl radical (·OH), and hydrogen peroxide (H2O2) as track segment yields (differential yields) under the conditions of neutral pH. With increasing LET, the g values of e− aq and ·OH decrease from 2.4 and 2.6 in 4He2+ radiolysis to 0.9 and 1.1 (100eV)−1 in 56Fe26+ radiolysis, respectively. It was also found that the primary g value of e− aq is smaller than that of ·OH for any type of ion beam. For the 12C6+ beam, other energies such as 290, 220, 135MeV/u were taken for the irradiation to investigate the effects of type or atomic number of ions on the measured yields. Furthermore, effects of dissolved oxygen on enhancement of H2O2 production have also been investigated with aerated NaNO3 solutions. The presence of dissolved oxygen caused 15–35% enhancement in H2O2 yields for all beams. In addition, the results of the present work were compared with reported track segment yields. [Copyright &y& Elsevier]

Abstract: The absorption spectra of solvated electrons in 1-propanol and 2-propanol have been investigated from 22 to 270°C at a fixed pressure of 7MPa, by using both nanosecond pulse radiolysis and laser photolysis techniques. The results show that, even up to supercritical conditions, it is still possible to measure unambiguously the absorption spectra of solvated electron in these two propanols. The peak positions of the absorption spectra show a red-shift (shifts to longer wavelengths) as temperature increases, similar to water and other alcohols, but the temperature efficiency, dE max/dT, of 1-propanol is larger than that of 2-propanol. In addition, in clear contrast to that of pulse radiolysis, in laser photolysis experiments, an increase in the maximum absorbance of the absorption spectra of solvated electron with temperature up to ∼200°C is attributed to the increase of absorbance (CTTS absorption band) of I− anion at 248nm with increasing temperature. [Copyright &y& Elsevier]

Abstract: γ-Radiolysis and pulse radiolysis of phenol in aqueous solution up to supercritical condition have been carried out. G-values of phenol consumption and product formation have been determined. While dihydroxybenzenes were major products at room temperature, multi-ring compounds and benzene were formed above 300°C. This indicates reaction mechanism was changed above 300°C, where phenoxyl radical plays a predominant role. This is supported by the observation of phenoxyl radical in pulse radiolysis. In supercritical water, the G-values increased with decrease of density. [Copyright &y& Elsevier]

Abstract: A product analysis study of γ-irradiated benzophenone aqueous solutions from room temperature to 400°C has been carried out by the combination of a flow irradiation system and a liquid chromatographic method. At room temperature, the main decomposition products are phenol and hydroxybenzophenone isomers. In high temperature and supercritical water solutions, 9-fluorenone appears as an important product and the G-value of benzophenone consumption depends significantly on the water density under supercritical conditions. [Copyright &y& Elsevier]

The large-scale synthesis and the stabilization of noble metal nanocatalysts with ultrasmall sizes are crucial to their practical application. Herein, Pd, Au, and Pt nanoparticles (NPs) are in situ embedded on boron nitride nanosheets (BNNSs) via the reduction of precursor salts induced by 60Co γ-irradiation, which is a mature technique widely used in industry. The reduction mechanism was elucidated by pulse radiolysis experiments. In comparison with other BN substrates like hexagonal BN (h -BN), BNNSs had not only large surface area of 263 m2 g−1, but also abundant hydroxyl groups produced during the sonicated exfoliation, resulting in ultrasmall sizes, large loading amounts, and uniform distribution of the anchored NPs. The particle sizes of the loaded Pd, Au, and Pt NPs were measured to be 2.9, 3.1, and 3.0 nm, respectively. As a consequence, in the model reaction of 2-nitroaniline reduction, the Pd-, Au- and Pt-BNNSs composite nanocatalysts showed much higher catalytic activities than those composites loading the corresponding NPs on other BN substrates. Particularly, most of the 2-nitroaniline could be reduced within merely 40 s when using Pd-BNNSs as catalysts, performing a rate constant of 1.1 × 10−1 s−1. The number of hydroxyl groups on BNNSs support as well as the catalytic performance of the corresponding NPs-loaded BNNSs composites could be improved by extending the sonicated exfoliation time, because more NPs were loaded and the hydroxyl groups were also proved to play an important role in enhancing the catalytic activity. Moreover, Pd-BNNSs catalysts still displayed prominent activity even after five cycles owing to the high stability of BNNSs and their strong affinity for PdNPs. This work not only demonstrates BNNSs as ideal supports to load noble metal NPs for catalysis, but also reveals the feasibility to synthesize and in situ embed ultrasmall noble metal NPs on BNNSs via γ-irradiation. γ-Radiation-induced reduction achieved facile loading of noble-metal nanoparticles on BNNSs as ideal supports for extraordinary catalytic activity and excellent reusability. [Display omitted] • BNNSs with hydroxyl groups, prepared from sonicated exfoliation, were suitable to load noble metal nanoparticles (NPs). • Noble metal NPs of Pd (Au or Pt) were in situ embedded on BNNSs by facile γ-radiation-induced reduction. • The reduction mechanism was elucidated by pulse radiolysis experiments. • NPs loaded on BNNSs possessed the smaller sizes and higher loading amounts, compared with those on other BN substrates. • NPs-loaded BNNSs showed excellent catalytic activity and reusability for 2-nitroaniline reduction. [ABSTRACT FROM AUTHOR]

Transient radicals (hydrated electron, (SCN)[sub 2][sup .-] and CO[sub 3][sup .-]) formed in supercritical water have been observed by the pulse radiolysis technique. The change of spectra of these radicals with temperature has been measured. It was found that the spectra and absorption coefficients of the radicals, e[sup -][sub aq] and (SCN)[sub 2][sup .-], are strongly dependent on the temperature of the water. Since it was found that the absorption spectrum and molar absorption coefficient of CO[sub 3][sup .-] radical seem to be almost independent of temperature, G-values of OH and e[sup -][sub aq] could be derived. Then, the absolute values of the absorption coefficients for the radicals could be calculated. The G-values of the radical products in water radiolysis tend to increase with increasing temperature up to 400°C. Based on the above observation, radiolysis of supercritical water is discussed. [ABSTRACT FROM AUTHOR]

• BCN was successfully modified by silane coupling agent. • The mechanical properties of SR were enhanced by BCN after irradiation. • BCN decreased the radiation crosslinking of SR. • BCN lessened the gas generated by SR side chain after irradiation. • The mechanism of BCN to improve the radiation resistance of SR was explained. The developing nuclear technology has increased the need for radiation-resistant and shielding materials. It is crucial to study the radiation resistance of polymers in order to prevent safety incidents brought on by the degradation of polymer performance in a nuclear environment. In this work, γ-aminopropyltriethoxy silane (KH550) was successfully grafted onto carbon-doped boron (BCN) to obtain modified BCN (BCN-KH550), then BCN-KH550 was added in silicone rubber and refined and vulcanized. The elongation at break of silicone rubber composite doped with 0.3 phr BCN-KH550 can retain (54 ± 2)% of the initial value. The addition of BCN and BCN-KH550 both increases the initial decomposition temperature of the irradiated SR. The radiation caused changes in crystallinity and glass transition temperature (T g) were measured using differential scanning calorimetry. The difference T g of BCN-KH550/SR0.3 before and after irradiation is 0.9 °C higher than that of SR. It is supposed that BCN protects the side group of SR during irradiation through differential thermogravimetric analysis curve and gas phase infrared spectra of the irradiation-induced gas products. BCN and BCN-KH550 can lower the hydrocarbon, CO 2 and CO production by side chain breakdown in both air and nitrogen atmospheres. The presence of BCN and BCN-KH550 decrease the radiation crosslinking of SR. The outcomes demonstrate that BCN-KH550 can reduce the effects of γ-radiation crosslinking on SR by declining side chain decomposition. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effect of the structure for four extractants was systematically re-visited. • Complexation properties of UO 2 2+ complexes were investigated by DFT calculations. • QTAIM analysis indicated that U–O (P=O) bonds were ionic characteristics. • The results laid theoretical foundation for selection of organophosphorus extractant. In the present work, the effects of four neutral phosphorus extractants (TBP, TAP, THP, TEHP) with different molecular structures on the extraction behaviors towards U(Ⅵ) and radiation stability were systematically studied. The results of the batch extraction and the γ-radiolysis experiments manifested that the extraction performance and radiation stability of the four extractants followed the order of TEHP > THP > TAP > TBP. Moreover, DFT calculations and Multiwfn software were utilized to analyze the properties of the extractants. The electrostatic potentials (ESP) and frontier molecular orbital of extractants indicated that the nucleophilic ability was ranked as TEHP > THP > TAP > TBP. The analyses of quantum theory of atoms in molecules (QTAIM) and Wiberg indices (WBIs) revealed that the UO 2 2+ ions exhibited stronger complexation ability with O atoms in TEHP compared to the other three extractants. The bonds between UO 2 2+ ions and extractants were primarily ionic in nature. From the energetic perspective, the thermodynamic energy demonstrated that the Gibbs free energy of TEHP in aqueous solution was the most negative, implying that it should be easier to combine with UO 2 2+. This work elucidates that the increase of alkyl chain length and the presence of branched chains can enhance the extraction performance and radiation stability of neutral phosphorus extractants. It not only lays the theoretical foundation for designing novel organic phosphorous extractants with superior extraction performance and high radiation stability, but also provides scientific basis for the extraction process of uranium in spent nuclear fuel reprocessing. [ABSTRACT FROM AUTHOR]

This article investigated the solubility of platinum group metals (PGMs) in sodium borosilicate glass and its effect on the viscosity and electrical conductivity of melts. The role of PGMs in the viscosity and electrical conductivity of melts was examined using the rotating cylinder method and impedance spectroscopy, respectively. Moreover, XRD, XPS, and SEM were used to measure the phase compositions, valence states, and microstructures, respectively, of the glass samples with different PGMs contents. The results showed that the solubility of Pd and Rh in sodium borosilicate glass was estimated to be less than 110 ppm by weight. The higher concentrations of Pd and Rh resulted in Pd-rich and Rh-rich inclusions in the glass matrix, which eventually agglomerated to form metallic Pd, Rh and Rh 2 O 3. The evolution of viscosity and electrical conductivity with different temperatures followed the Arrhenius equation with a fairly good linear relationship between ln η and ln κ. • The solubility of PGMs in borosilicate glass was less than 110 ppm by weight. • The aggregation and crystallization trends of PGMs in glass were investigated. • The temperature dependence of viscosity and conductivity of glass melts obeyed Arrhenius equation at high temperature region. • The viscous/electrical activation energy of glass melts containing 0–1 wt% PGMs was calculated. • The impact of PGMs concentration on the structure of PGMs aggregates had a nonlinear threshold effect. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The MEC extractor can achieve high extraction performance and fast phase separation. • Its solution tank can be used for mixing and clarification simultaneously. • It can extract metal ions of different concentrations with low organic consumption. • Valid empirical formulas were established to predict the extraction behavior. Abstract Solvent extraction is an important method for purification and separation in industrial applications. In this study, we develop a membrane emulsification circulation (MEC) extractor with simple structure, whose solution tank serves as mixing and clarification chamber simultaneously. Compared to conventional stirring extraction, the MEC extractor achieves better extraction performance of Pd(II) using Cyphos IL 101 as extractant since membrane emulsification produces smaller droplets and lager mass transfer area. The effects of volume ratio of organic and aqueous phase (O / A), molar ratio of ligands and metal ions (L / M), and Pd(II) concentration on extraction are systematically studied, revealing that the circulation extraction significantly reduces the consumption of extractant and diluent. Over 99% of Pd(II) is extracted at low O / A and L / M ratios, even with an extremely low concentration of 0.001 mM. Further investigations on parameters of the MEC extractor suggest that smaller pellet size of the sintered polyethylene membrane and higher flow rate benefit the extraction. Empirical formulas showing good agreement with the experimental data are established to predict the residual concentration of metal ions in aqueous phase. Moreover, Pd(II) and other precious metals widely used in electronics like Au(III) and Pt(IV) can be also efficiently and selectively extracted from simulated waste electrical and electronic equipment leachate by Cyphos IL 101 using the MEC extractor, and the extraction efficiency is 92.8% for Pt(IV), over 99.9% for both Pd(II) and Au(III). The MEC extractor exhibits great potential in practical application due to its simple structure, high economic benefits and extraction performance. [ABSTRACT FROM AUTHOR]

Background: Precise diagnosis of the tissue origin for metastatic cancer of unknown primary (CUP) is essential for deciding the treatment scheme to improve patients' prognoses, since the treatment for the metastases is the same as their primary counterparts. The purpose of this study is to identify a robust gene signature that can predict the origin for CUPs.Methods: The within-sample relative gene expression orderings (REOs) of gene pairs within individual samples, which are insensitive to experimental batch effects and data normalizations, were exploited for identifying the prediction signature.Results: Using gene expression profiles of the lung-limited metastatic colorectal cancer (LmCRC), we firstly showed that the within-sample REOs in lung metastases of colorectal cancer (CRC) samples were concordant with the REOs in primary CRC samples rather than with the REOs in primary lung cancer. Based on this phenomenon, we selected five gene pairs with consistent REOs in 498 primary CRC and reversely consistent REOs in 509 lung cancer samples, which were used as a signature for predicting primary sites of metastatic CRC based on the majority voting rule. Applying the signature to 654 primary CRC and 204 primary lung cancer samples collected from multiple datasets, the prediction accuracy reached 99.36%. This signature was also applied to 24 LmCRC samples collected from three datasets produced by different laboratories and the accuracy reached 100%, suggesting that the within-sample REOs in the primary site could reveal the original tissue of metastatic cancers.Conclusions: The result demonstrated that the signature based on within-sample REOs of five gene pairs could exactly and robustly identify the primary sites of CUPs. [ABSTRACT FROM AUTHOR]

Predicting the electrical corrosion potential (ECP) of type 304 stainless steel, the structural material of recirculation pipes in fusion power plants, is important because the growth rate of intergranular stress corrosion crack (IGSCC) of 304 stainless steel is closely related to ECP. In this work, a new model has been developed, by modifying existing models, to calculate the ECP of recirculation pipes in future fusion power plant. The calculation results indicate that merely injecting hydrogen cannot reduce ECP below EIGSCC if the dose rate exceeds a threshold, other assisted water chemistry controlling method is necessary. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Magnetic Nb-CST, which can be separated easily by an external magnetic field, is able to eliminate Sr2+ and Cs+ at ppb level. • Besides excellent selectivity towards Sr2+ and Cs+, it is able to separate them from each other by adjusting pH. • Even in real seawater, magnetic Nb-CST can remove as high as 94.19% of Cs+ at ppb level. • Its high radiation stability and acid-resistance benefit the treatment of radioactive liquid wastes. Abstract In this work, magnetic Nb-substituted crystalline silicotitanate (mag-Nb-CST), which can be used for separation of Sr2+ and Cs+ from aqueous solution, is successfully synthesized by embedding amine-functionalized Fe 3 O 4 into the Nb-substituted crystalline silicotitanate (Nb-CST), being characterized by various techniques such as XRD, SEM, EDS, XPS, and VSM. The studies on the adsorption behaviors show that the adsorption process reaches equilibrium within about 8 h, and the maximum adsorption capacity on mag-Nb-CST is 14.38 mg g−1 at pH 11.00 for Sr2+, and 11.18 mg g−1 at pH 4.00 for Cs+, respectively. Besides the excellent selectivity towards Sr2+ and Cs+ over various lanthanides and actinides, the pH dependence on the adsorption capacity suggests a possibility to separate Sr2+ and Cs+ from each other by simply adjusting pH. Mag-Nb-CST is able to remove most of the Sr2+ and Cs+ at ppb level. Even in real seawater, it is able to remove 94.19% of Cs+. Moreover, mag-Nb-CST shows good acid-resistance and radiation stability. The crystal structure and morphology remained almost the same after γ-irradiation with an adsorbed dose up to 435.8 kGy. Most importantly, only less than 0.1% of Fe is leached out from mag-Nb-CST at pH > 2, indicating that the embedded Fe 3 O 4 nanoparticles are protected from corrosion by the coated Nb-CST, which is in favor of elimination of Sr2+ and Cs+ in acidic solutions. Thus, mag-Nb-CST is a promising adsorbent in the treatment of acidic radioactive liquid wastes, and the purification of contaminated seawater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Radiolysis mechanism and radiolytic pathways of DAPhen were investigated. • Radiolysis of DAPhen is mainly through the cleavage of amide bonds and N C bonds. • HNO 3 enhanced the extraction and An/Ln separation performance of DAPhen after irradiation. • Radiolytic products of DAPhen were verified by DFT calculations to have extraction ability for U. The stability of organic extractant molecules against radiolysis is critical in the field of actinides and lanthanides (An/Ln) separations. In order to evaluate the radiolytic effects on the extraction performance, the solutions of N,N '-diethyl- N,N '-ditolyl-2,9-diamide-1,10-phenanthroline (Et-Tol-DAPhen) in n -octanol were subjected to γ-irradiation in the presence and absence of 3 mol/L HNO 3 aqueous phase. Et-Tol-DAPhen diluted in n -octanol was almost completely decomposed after irradiation and exhibits decreased extraction ability at an absorbed dose of about 384 kGy, along with the appearance of various degradation products. Et-Tol-DAPhen, which was diluted in n -octanol, was completely decomposed upon irradiation in the presence of 3 mol/L HNO 3 aqueous phase. However, it exhibited higher D U and SF U/Eu values than before irradiation, as well as degradation products that were also generated. The structures of some isomers of radiolytic products were investigated by density functional theory (DFT) calculations, the radiolysis pathways and products of Et-Tol-DAPhen extractants were obtained, and the radiolysis pathways and products of Et-Tol-DAPhen extractants was proposed. The radiolytic products mainly originated from amide bond and N C bond cleavage of side group substituents, and some resulted from interaction with n -octanol radicals generated during radiolysis. The presence of HNO 3 can inhibit the radiolysis of Et-Tol-DAPhen to a certain extent and cause enhanced extraction ability. Moreover, the DFT calculations reveal that the radiolytic products produced in presence of 3 mol/L HNO 3 aqueous phase also have efficient extraction performance towards UO 2 2+. The understanding of the radiolysis pathways and products of extractants, based on radiation chemical effects is expected to be helpful for developing new strategies for extractants with long-term performance. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Fast reaction rate and high separation ratio of Re from aqueous solution were performed by γ irradiation. • Re(0) was produced together with ReO 2 and ReO 3 for the first time by γ irradiation. • Both steady state study and pulse radiolysis study were conducted. • OH− was believed to be coordinated with Re(VI) thus affecting the reaction rate. Abstract Rhenium (Re) is a good nonradioactive alternative of technetium-99 (99Tc), which is a β emitter causing long-term radioactive toxicity due to its long half-life and high yield in nuclear reactors. TcO 4 −, the dominant form of 99Tc, is very easy to migrate in the environment because of its high solubility. In this work, γ irradiation was applied to separate rhenium from aqueous solution in the presence of isopropanol. Re(VII) was reduced by hydrated electrons (e aq −) generated from γ-radiolysis of water, leading to the formation and precipitation of Re(0) and rhenium oxides (ReO 2 and ReO 3) nanoparticles. It was the first time that Re(0) was observed in the reduction products of Re(VII) by γ irradiation, which was confirmed by HR-TEM, EDX, XPS and XRD. The reduction of Re(VII) by γ irradiation was very fast and efficient in alkaline condition, whose separation ratio reached 93.6% after 2-h irradiation and the final separation ratio was as high as 98.1%. Increase in absorbed dose rate, isopropanol concentration, and pH, was conducive to the separation of Re overall. Further studies on the transient species by pulse radiolysis revealed that OH− might coordinate with the intermediate Re(VI) forming different complexes with different concentrations of OH−, thus affecting the reduction of Re(VII). This work not only demonstrates that γ irradiation could be a promising method for the efficient separation of Re(VII), but also gives a better understanding in the reaction mechanism. [ABSTRACT FROM AUTHOR]

A Li + -OH − exfoliation system was designed to prepare graphene in water without surfactants or sonication. Due to the positive charge transferred from intercalating Li + ions to adjacent C atoms, OH − could add on the graphene sheets and further promote their affinity to water, resulting in efficient exfoliation of graphene in water. The as-prepared graphene concentration was up to 0.09 mg·mL −1 , and sheet sizes range from 1 to 2 μm. Detailed characterizations revealed the formation of high-quality and few-layer graphene sheets and confirmed the addition of hydroxyl groups on graphene sheets during exfoliation. This strategy has potential in scalable production of graphene in aqueous phase. [ABSTRACT FROM AUTHOR]

The separation and recovery of U(VI) and Th(IV) from rare earths are very important to avoid environmental pollution. A functional fibrous hierarchically bimodal mesoporous silica (F-SiO-DP) as an high efficient adsorbent for selective adsorption of uranium and thorium, which had hierarchically bimodal mesoporous structure and specific surface area of ca. 474.1 m g, was prepared by post-modification method using 2,9-diamide-1,10-phenanthroline. The synthesized adsorbent was characterized by HR-TEM, SEM, FT-IR, N adsorption-desorption, TGA techniques, XRD and NMR spectroscopy. The effects of pH, contact time, initial U(VI) and Th(IV) concentration, temperature and the presence of competitive metal ions on U(VI) and Th(IV) adsorption behavior were studied in detail. The hierarchically bimodal mesoporous structure endows F-SiO-DP with faster adsorption rate, which can reach equilibrium within 10 min, as well as higher adsorption capacities for U(VI) and Th(IV) compared with unimodal mesoporous silica like MCM-41 functionalized with 2,9-diamide-1,10-phenanthroline. The maximum adsorption capacities reach 416 mg g for U(VI) at pH 5.0 and 277 mg g for Th(IV) at pH 3.8, which are much higher than most of previously reported mesoporous silica-based adsorbents. The selectivity coefficient of U(VI) and Th(IV) over Ce(III), Nd(III), Sm(III), Eu(III), Gd(III), Y(III) and Yb(III) is all larger than 9 at pH 3.8, indicating that F-SiO-DP possesses a good simultaneously selective adsorption performance for U(VI) and Th(IV). This work demonstrates that F-SiO-DP with hierarchically bimodal mesoporous structure has promising application in adsorption and separation of actinides from lanthanides, which is crucial to the environmental protection. [ABSTRACT FROM AUTHOR]

Predicting the effects of coolant water radiolysis induced by neutron and gamma radiation in the International Thermonuclear Experimental Reactor (ITER) is important, as oxidizing species like O 2 and H 2 O 2 will corrode structural materials, increasing maintenance costs and potentially compromising safety. In this work, a new model has been developed, by modifying existing models, to evaluate the water radiolysis behaviors in different Primary Heat Transfer Systems (PHTSs) in ITER. The new model takes the circulation of coolant, and the combined gamma and 14 MeV neutron radiation into consideration. We recommend injection of about 5 cc H 2 under standard temperature and pressure (STP) per kilogram of H 2 O into the First Wall/Blanket (FW/BLKT) PHTS to both efficiently suppress water radiolysis and avoid problems caused by addition of excessive H 2 . [ABSTRACT FROM AUTHOR]

The extraction and separation of uranium (U(VI)) and thorium (Th(IV)) from rare earth elements (REEs) in acidic waste solutions is very important and still challenging. In this paper, a high-efficient sorbent was successfully prepared by functionalization of graphene oxide with phenanthroline diamide (GO-PDA), which exhibited excellent selectivity towards actinides over lanthanides. The sorption behaviors of GO-PDA towards U(VI) and Th(IV) under various conditions were evaluated by batch experiment. Fast sorption kinetics and high sorption capacities were realized for both U(VI) and Th(IV), which reached equilibrium in 60 min. The sorption isotherms of both U(VI) and Th(IV) coincided with Langmuir model, while the maximum sorption capacities of U(VI) (pH = 5.5) and Th(IV) (pH = 4.0) at 298 K were calculated to be 718 and 703 mg/g respectively, which were much higher than most of the previously reported graphene oxide (GO) based sorbents. GO-PDA also possessed significantly enhanced selectivity for U(VI) and Th(IV) over Eu(III), Nd(III) and Sm(III) compared to pristine GO at ultralow low pH (0−2), with separation factors larger than 23 at pH 0. Most importantly, GO-PDA was made into membrane with porous structure, which achieved fast and efficient separation of U(VI) and Th(IV) from Eu(III), Nd(III) and Sm(III) in aqueous solution. This work demonstrates that GO-PDA is a promising sorbent for efficient selective separation of U(VI) and Th(IV) from REEs in strong acidic waste solutions, which is of great value for nuclear waste management and nuclear fuel recycling. [ABSTRACT FROM AUTHOR]

The separation and recovery of Li+ from high-ratio Mg/Li salt lake brines possess a big significance, especially the demand for Li+ has grown rapidly in recently years. The ionic liquid [C 2 mim][NTf 2 ] with tributyl phosphate (TBP) and sulfonated kerosene system was hired as an extractant to extract Li+ from salt lake brines with a high-ratio of Mg/Li experimentally by using a homemade membrane emulsification circulation (MEC) extractor. From the single-element extraction, the extraction efficiency of Li+ could be up to 96.0 % within 8 min. In view of the multi-element experiment, the MEC extractor manifested better extraction performance compared with oscillating and stirring extraction. The extraction ability of the extractant for Li+ could reach the ideal level without the addition of any co-extraction agents (Fe3+ and ClO 4 −). The new extraction system could have extensive applications since the extraction performance was insensitive to pH and temperature. The optimal extraction conditions for Li+ were V TBP : V [C 2 mim][NTf 2 ]: V kerosene = 8:1:1, R(O/A) = 1. In addition, the stripping efficiency of Li+ could be improved by increasing the A/O and stripping stage. When the stripping stage reached 3, 94.5 % of Li+ could be extracted successfully by using 2 mol/L HCl. The slope method and FT-IR analysis manifested that the TBP-[C 2 mim][NTf 2 ]-sulfonated kerosene system extracted Li+ by an anion coordination mechanism in the form of [Li·2TBP]+ org. The DFT calculations were used for revealing the reaction between Li+ and P = O. The results are expected to provide experimental data and a theoretical basis for practical application. Fast and high-efficiency separation for Li+/Mg2+ from salt lake brines by a homemade membrane emulsification circulation (MEC) extractor using the TBP-[C 2 mim][NTf 2 ]-sulfonated kerosene system as an extractant could be achieved with an extraction efficiency of 85.0 % for Li+ and only 2.0 % for Mg2+ within 6 min. [Display omitted] • The ionic liquid [C 2 mim][NTf 2 ] could effectively strengthen the extraction performance. • The proposed novel extraction system represented good selectivity for Li+/Mg2+. • DFT calculations and FT-IR analysis indicated that Li+ mainly combined with P = O in TBP. • Fast and efficient separation of Li+/Mg2+ could be achieved by the MEC extractor. • A process for extracting Li+ from salt lake brines was proposed. [ABSTRACT FROM AUTHOR]

The extraction and separation of platinum group metals (PGMs) from HLLW is of great value for resource recycling and the running of reprocessing plants. In this paper, the photochemical method was proposed to extract and separate PGMs (Pd, Ru) from simulated high level liquid wastes (HLLW). Pd and Ru metal were extracted from aqueous solution by photoreduction with high efficiency (reduction ratio >90%) in the presence of alcohols, which was confirmed by UV–vis spectroscopy, XRD, XPS and TEM analysis. The effects of various parameters such as exposure wavelength, reducing agents, Cl − and pH value were investigated to optimize the photoreaction. The highly efficient extraction and separation of Pd or/and Ru metal from their mixture with lanthanide (Nd) by selective photoreduction was realized. The results suggest that the photochemical method is a promising method for the efficient extraction and separation of PGMs from HLLW. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchically porous boron nitride (HPBN) was modified with diamide pyridine (DAPy). • Assistance of radiation-induced hydroxylation was essential to modify inert HPBN. • Hierarchically porous structure endowed HPBN-DAPy ultrafast adsorption kinetics. • HPBN-DAPy selectively adsorbed U due to the strong affinity between uranyl and DAPy. • HPBN-DAPy retained 86% of the original adsorption amount after 5 cycles. Uranium (U) released by nuclear accident raises concerns about human health owing to its long half-life and toxicity. Diamide-pyridine-modified hierarchically porous boron nitride (HPBN-DAPy) was prepared for efficient removal of U. HPBN, which could hardly adsorb U, gained the ability to uptake U only after functionalization with diamide pyridine (DAPy) groups. The hierarchically mesoporous structure with bimodal mesopores around 20 and 3 nm endowed HPBN-DAPy with unique adsorption kinetic. Uranyl ions (UO 2 2+) easily approached the adsorption sites in those large mesopores and thus the adsorption rapidly reached temporary equilibrium within 0.5 min with a relatively high adsorption of amounts (q e) of 87.5 mg g−1 (adsorbent dosage = 0.4 g L−1, [U] 0 = 100 mg L−1, pH = 4.0 ± 0.1, T = 298 ± 1 K), which was beneficial for rapid decontamination. Small mesopores and the inner large mesopores, which were connected through small mesopores, provided extra adsorption sites, leading to a further increased q e of 115.7 mg g−1 after achieving final equilibrium. Investigation of adsorption mechanism showed that UO 2 2+ were chemically adsorbed in monolayer at a low initial concentration while they were physically adsorbed in the form of polynuclear complexes at a high initial concentration. Benefited from the strong affinity between UO 2 2+ and DAPy, HPBN-DAPy performed excellent selectivity for UO 2 2+ toward other most concerned radionuclide ions. Furthermore, HPBN-DAPy also exhibited adequate salt tolerance and outstanding reusability, which should be promising in removal of U from contaminated water. [ABSTRACT FROM AUTHOR]

• BCN was surface modified with two silane coupling agents. • Composites exhibited excellent properties before and after gamma irradiation. • The performance of composites can be improved by improving the interfacial compatibility. • Modified BCN could weaken oxidative degradation of EP under γ irradiation. Polymer matrix composites reinforced with boron nitride (BN) have attracted much attention in the nuclear industry due to their attractive properties. Nevertheless, the performance of such composites largely depends on matrix–filler interactions. Herein, carbon-doped boron nitride (BCN), modified by two silane coupling agents, was used to fabricate epoxy composites, and the effect of gamma irradiation on the properties of epoxy resin composites was investigated. The research showed that the modified BCN/epoxy composites prepared herein exhibited excellent mechanical and thermal properties before and after gamma irradiation. The tensile strength of the composites increased up to 63.1 MPa at 0.5 wt % loadings compared to neat epoxy (54.7 MPa). After irradiation at 900 kGy, the tensile strength of the composites was 32.5% higher than that of neat EP. This improvement was ascribed to the excellent compatibility of the modified BCN and epoxy. Moreover, the char yield and the glass transition temperature significantly increased with incorporation of modified BCN before and after irradiation. The mechanism for the enhanced performance was that the barrier consisting of BN protected the matrix from further oxidative degradation. This study suggested that functionalized BN more effectively enhanced epoxy properties before and after irradiation. [ABSTRACT FROM AUTHOR]

[Display omitted] • BCN was functionalized by Phenanthroline diamide with high density. • Functionalized BCN exhibited ultrahigh adsorption capacity for U(VI). • Functionalized BCN showed excellent selectivity for U(VI) from lanthanides. • Adsorption mechanism was explored by combining two-site model and DFT calculations. Separating and recovering uranium (U(VI)) efficiently from lanthanides is crucial for mitigating the radioactive hazard generated by hydrometallurgical residual solutions of lanthanide minerals and ensuring the long-term sustainability of uranium resources. The present work exploited phenanthroline diamide functionalized porous carbon doped boron nitride (BCN-DAPhen) as an adsorbent, which displayed outstanding adsorption performance for the separation of U(VI) from lanthanides. The results of batch adsorption tests indicated that BCN-DAPhen exhibited rapid adsorption kinetics and the adsorption process achieved equilibrium within 10 min. BCN-DAPhen also performed ultra-high maximum adsorption capacity that was calculated to be 2050.8 mg g−1 by fitting with the two-site Langmuir model. Theoretical calculation and experimental results of adsorption were combined to illustrate the adsorption mechanism as well, the results showed that two structures of DAPhen groups on BCN performed discrepant adsorption properties for U(VI). BCN-DAPhen retained excellent adsorption ability owing to the strong affinity of DAPhen groups with U(VI) even in the solution with high concentration of salt and acid. The selectivity coefficients of U(VI) toward various lanthanides were beyond 192.5 at a high nitric acid concentration of 5 mol L−1. This study suggested a general technique for the functionalization of porous BCN, which is expected to be useful in the treatment of residual solution in lanthanides hydrometallurgy. [ABSTRACT FROM AUTHOR]

Solvatochromic shift of 4,4′-bpyH in aqueous solutions at elevated temperatures up to supercritical conditions and in various organic solvents with different dielectric constants, is investigated by pulse-radiolysis technique. 4,4′-bpyH shows a stronger solvent–solute interaction in water than in organic solvents, perhaps due to the hydrogen bond between 4,4′-bpyH and water. At 380 °C, local density augmentation, namely ρ local – ρ bulk , in supercritical water becomes 280 kg m −3 ( ρ bulk = 208 kg m −3 ), and the density enhancement factor is 8.9. Density fluctuation maximizes when ρ bulk is around 120 kg m −3 . Density inhomogeneity decreases as temperature rises, but is still remarkable at 400 °C. [ABSTRACT FROM AUTHOR]

The radiation-induced reactions of a water-soluble coumarin derivative, coumarin-3-carboxyl acid (C3CA), have been investigated in aqueous solutions by pulse radiolysis with a 35 MeV electron beam, final product analysis following 60Co γ-irradiations and deterministic model simulations. Pulse radiolysis revealed that C3CA reacted with both hydroxyl radicals (•OH) and hydrated electrons (e− aq) with near diffusion-controlled rate constants of 6.8 × 109 and 2.1 × 1010 M−1 s−1, respectively. The reactivity of C3CA towards O2• − was not confirmed by pulse radiolysis. Production of the fluorescent molecule, 7-hydroxy-coumarin-3-carboxylic acid (7OH-C3CA), was confirmed by final product analysis with a fluorescence spectrometer coupled to a high performance liquid chromatography (HPLC) system. Production yields of 7OH-C3CA following 60Co γ-irradiations depended on the irradiation conditions and ranged from 0.025 to 0.18 (100 eV) −1. Yield varied with saturating gas, additive and C3CA concentration, implying the presence of at least two pathways capable of providing 7OH-C3CA as a stable product following the scavenging reaction of C3CA with •OH, including a peroxidation/elimination sequence and a disproportionation pathway. A reaction mechanism for the two pathways was proposed and incorporated into a deterministic simulation, showing that the mechanism can explain experimentally measured 7OH-C3CA yields with a constant conversion factor of 4.7% from •OH scavenging to 7OH-C3CA production, unless t-BuOH was added. [ABSTRACT FROM AUTHOR]

[Display omitted] • A cationic-surfactant-assisted solvothermal exfoliation method was developed to prepare monolayer BNNSs. • Over 60% of the exfoliated BNNSs were monolayer with the assistance of CTAB. • DAPhen funtionalized BNNSs (BNNSs-DAPhen) achieved high adsorption amounts and ultrafast adsorption rate of U(VI). • BNNSs-DAPhen maintained good adsorption performance under high concentrations of acid and salts. • BNNSs-DAPhen performed excellent selectivity for U(VI) over lanthanides in strongly acidic conditions. The efficient separation and recovery of uranium(VI) (U(VI)) from lanthanides is pivotal to reduce the radioactive threat of hydrometallurgical residue solution of lanthanide minerals and benefits the sustainability of U resources. Here, we develop a cationic-surfactant-assisted solvothermal exfoliation method to prepare monolayer boron nitride nanosheets (BNNSs) for the ultrafast and selective separation of U(VI) from lanthanides. With the assistance of the strong "cation–π" interaction between cationic surfactants and BN, the monolayer BNNSs were prepared. Functionalization with diamide phenanthroline (DAPhen) groups endows the pristine BNNSs, which can hardly adsorb U(VI), with outstanding U(VI) adsorption performance. Batch adsorption experiments demonstrate that the obtained DAPhen modified BNNSs (BNNSs-DAPhen) exhibited high maximum adsorption capacity and ultrafast adsorption kinetics. The adsorption process reached equilibrium less than 1 min and the maximum adsorption capacity was estimated to be 313 mg g−1 by fitting with Langmuir model. Even under high concentrations of salts and acids, BNNSs-DAPhen still maintained excellent adsorption performance owing to the strong complexing ability of DAPhen groups with U(VI). The selectivity coefficients of U(VI) toward various lanthanides including lanthanum(III), cerium(III), europium(III), gadolinium(III), ytterbium(III), and lutetium(III) were beyond 120 at a high nitric acid concentration of 5 mol L−1. This work proposed a universal strategy for the production of monolayer BNNSs and the subsequent functionalization, which might be promising in the treatment of residual solution for lanthanides hydrometallurgy and decontamination of U(VI). [ABSTRACT FROM AUTHOR]