‘Jinxiu' is a processing apricot(Armeniaca vulgaris L.) cultivar derived from the cross of ‘Chuanzhihong'בJintaiyang'.The fruit is oval-shaped with the ground color of orange and 1/4-1/2 sheet red...‘Jinxiu' is a processing apricot(Armeniaca vulgaris L.) cultivar derived from the cross of ‘Chuanzhihong'בJintaiyang'.The fruit is oval-shaped with the ground color of orange and 1/4-1/2 sheet red in the surface. The average fruit weight is65.5 g, and the maximum value is 106 g. The flesh is orange, fine with very less fiber, toughness, less juice and freestone, and tastes sour and sweet. The soluble solid content is 12.5%. The edible rate is 95.8%. The fruit skin hardness is 12.9 kg/cm2 and storable. The preserved apricots have orange color and are tasty. The preserved yield is 40%. The fruit development period is 72 d. The fruit has high yield, and the fruit yield in full fruit period can reach 37 000 kg/hm2. ‘Jinxiu' was examined and approved by Hebei Examination and Approval Committee of Forest Tree Variety in 2013.展开更多
Uranium and molybdenum are important strategic elements. The production of ^(99)Mo and the hydrometallurgical process of uranium ore face difficult problems of separation of uranium and molybdenum.In this study, the f...Uranium and molybdenum are important strategic elements. The production of ^(99)Mo and the hydrometallurgical process of uranium ore face difficult problems of separation of uranium and molybdenum.In this study, the four phenanthroline diamide ligands were synthesized, and extraction and stripping experiments were performed under different conditions to evaluate the potential application of these ligands for separation of U(Ⅵ) over Mo(Ⅵ). With the growth of alkyl chain, the solubility of ligands could be greatly improved, and the separation effect of U(Ⅵ) over Mo(Ⅵ) gradually increased. The SF_(U/Mo) were around 10,000 at 4 mol/L HNO3. Three stripping agents were tested with the stripping efficiency of Na_(2)CO_(3)(5%) > H_(2)O > HNO_(3)(0.01 mol/L). The stripping percentages of the three stripping agents were all close to unity, indicating that the ligands had the potential to be recycled. The chemical stoichiometry of U(Ⅵ) complexes with ligands was evaluated as 1:1 using electrospray ionization mass spectrometry,ultraviolet visible spectroscopy and single-crystal X-ray diffraction. The consistency between theoretical calculation and experimental results further explains the coordination mechanism.展开更多
Although mesoporous silica with magnetically hybridized two-dimensional channel structures has been well studied in recent years,it remains a challenge to fabricate the counterpart with macroporous three-dimensional c...Although mesoporous silica with magnetically hybridized two-dimensional channel structures has been well studied in recent years,it remains a challenge to fabricate the counterpart with macroporous three-dimensional cubic structures since the highly acidic preparation conditions lead to dissolution of magnetic particles.Herein,we successfully prepared magnetic KIT-6 nano-composite and its amino derivatives by bearing acid-resistant iron oxide.The prepared materials exhibited excellent properties for U(VI)ions removal from aqueous solutions under various conditions.The experimental data show that the U(VI)adsorption features fast adsorption kinetics,high adsorption capacity and ideal selectivity toward U(VI).The adsorption process is of spontaneous and endothermic nature and ionic strength independence,and the adsorbents can be easily regenerated by acid treatment.Compared to pristine KIT-6,the introduction of magnetism does not reduce the efficiency of the material to remove U(VI)while exerting its role as a recovery adsorbent.The findings of this work further demonstrate the potential broad application prospects of magnetic hybrid mesoporous silica in radionuclide chelation.展开更多
Functionalized magnetic Fe_3O_4@SiO_2 composite nanoparticles were prepared by simply embedding iron oxide nanoparticles into MCM-41 through one-step synthesis process, followed by aminopropyls grafting on the mesopor...Functionalized magnetic Fe_3O_4@SiO_2 composite nanoparticles were prepared by simply embedding iron oxide nanoparticles into MCM-41 through one-step synthesis process, followed by aminopropyls grafting on the mesopore channels, aiming to efficiently and conveniently uptake U(VI) from aqueous solution. The resultant material possesses highly ordered mesoporous structure with large surface area, uniform pore size, excellent thermal stability, quick magnetic response, and desirable acids resistance, confirmed by Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), N_2 adsorption/desorption experiments, powder X-ray diffraction(PXRD), and thermogravimetric analysis(TGA). Detailed U(VI) sorption test indicated that this material is indeed an effective U(VI) sorbent with fast sorption kinetics of less than 2 h, large sorption capacity of 160 mg/g at p H 5.0±0.1, and desirable selectivity towards U(VI) ions over a range of competing metal ions. The absorbed U(VI) can be easily desorbed by 0.01 mol/L or more concentrated HNO_3 solution, and the reclaimed sorbent can be reused with no obvious decrease of sorption capacity even after 4 sorption-desorption cycles. The present results suggest the vast opportunities of this kind of magnetic composite on the solid-phase extraction of U(VI).展开更多
Electrochemical properties of rare-earth elements in the LiCl-KCl eutectic are important for the pyrometallurgical recycling process of spent nuclear fuels. In this work, the electrochemical properties of Tb(Ⅲ)/Tb(0)...Electrochemical properties of rare-earth elements in the LiCl-KCl eutectic are important for the pyrometallurgical recycling process of spent nuclear fuels. In this work, the electrochemical properties of Tb(Ⅲ)/Tb(0) couple were studied by the cyclic voltammetry(CV) at a liquid Zn pool electrode. The results showed that this electrochemical reaction is quasi-reversible with mixed reversible diffusion control and the charge transfer control. The diffusion coefficient of Tb(Ⅲ) was determined to be in the order of ~10.5 cm2 s.1. Moreover, kinetic parameters, such as the standard rate constants(ks) and charge transfer coefficient(α) for the electroreduction of Tb(Ⅲ) to Tb(0) at the liquid Zn electrode, were calculated by the Nicholson method at 873 K. Additionally, it was found that Tb-Zn intermetallic compounds were easily to be formed in the measurements. Hence, the reduction process of Tb(Ⅲ)/Tb(0) couple on the Zn-coated Mo electrode was also studied to obtain more information of the Tb-Zn intermetallic compounds. Electrochemical signals stemming from various intermetallic compounds associated with TbZn12, Tb2Zn17, Tb13Zn58, Tb3Zn11, TbZn3, TbZn2 and TbZn, were observed. The thermodynamic data were thereafter estimated by applying the emf method at 823–923 K. The standard formation Gibbs energies and the standard equilibrium constant of each Tb-Zn intermetallic compounds were also calculated. Finally, enthalpies and entropies of formation and the apparent standard potentials of various Tb-Zn intermetallic compounds were also obtained.展开更多
This work presents the electrochemical properties of gadolinium(Gd), a significant rare earth element in spent nuclear fuel(SNF), in the LiCl-KCl eutectic. To explore thermodynamic properties of Gd at the liquid galli...This work presents the electrochemical properties of gadolinium(Gd), a significant rare earth element in spent nuclear fuel(SNF), in the LiCl-KCl eutectic. To explore thermodynamic properties of Gd at the liquid gallium(Ga) electrode, experiments were performed both on the inert tungsten(W) and liquid gallium(Ga) electrode at different temperatures in a range from 723 to 823 K, which show that the Gd metal can be oxidized to Gd(Ⅲ) by exchanging of 3 electrons. Electrochemical techniques including cyclic voltammetry(CV), open circuit potential(OCP), potentiostatic electrolysis and galvanostatic electrolysis were utilized to detect the electrochemical behavior and evaluate standard apparent potential of the Gd(Ⅲ)/Gd couple,and E(Gd(Ⅲ)/Gd)*=-3.456 + 6.2×10-4T(±0.046)( vs Cl2/Cl-) is obtained.In addition, electromotive force(EMF) and coulometric titration were employed to calculate the activity and activity coefficient of Gd in metal Ga. After calculation, the activity is 1.791×10-15at 723 K and function of activity coefficient and temperature is lgγ = 3.485-10927/T(±0.0875).展开更多
Although solid-phase extraction is a useful approach for metal ion separation from aqueous solutions,existing sorbents suffer from low extraction effici-encies and/or instability when in contact with strong acidic med...Although solid-phase extraction is a useful approach for metal ion separation from aqueous solutions,existing sorbents suffer from low extraction effici-encies and/or instability when in contact with strong acidic media.We report here the first study on rational design and fabrication of phosphonate-decorated covalent organic frameworks,COF-IHEP1 and COF-IHEP2,for efficient and selective extraction of of uranium(VI)[U(VI)]and plutonium(IV)[Pu(IV)]from highly acidic solutions.展开更多
The issue of covale nee of acti nide complexes remai ns con troversial to date.The in troducti on of 2-phosphaethy nolate anion into acti・nide complexes is expected to in vestigate the reaction mode and the bon ding p...The issue of covale nee of acti nide complexes remai ns con troversial to date.The in troducti on of 2-phosphaethy nolate anion into acti・nide complexes is expected to in vestigate the reaction mode and the bon ding property.Herei n,we describe the function alizatio n of An(Tren^(TIPS))CI(1:An=U;2:An=Th)precursors with NaOCP(dioxane)_(2.5) through salt-elimination method leading to the formation of the corresponding uranium and thorium phosphaethynolate species:[U(Tren^(TIPS))(OCP)]⑶and[Th(Tren^(TIPS))(OCP)](4).展开更多
Although metal–organic frameworks offer a new platform for developing versatile sorption materials,yet coordinating the functionality,structure and component of these materials remains a great challenge.It depends on...Although metal–organic frameworks offer a new platform for developing versatile sorption materials,yet coordinating the functionality,structure and component of these materials remains a great challenge.It depends on a comprehensive knowledge of a“real sorption mechanism”.Herein,a ternary mechanism for U(Ⅵ)uptake in metal–organic frameworks was reported.Analogous MIL-100s(Al,Fe,Cr)were prepared and studied for their ability to sequestrate U(Ⅵ)from aqueous solutions.As a result,MIL-100(Al)performed the best among the tested materials,and MIL-100(Cr)performed the worst.The nuclear magnetic resonance technique combined with energy-dispersive X-ray spectroscopy and zeta potential measurement reveal that U(Ⅵ)uptake in the three metal–organic frameworks involves different mechanisms.Specifically,hydrated uranyl ions form outer-sphere complexes in the surface of MIL-100s(Al,Fe)by exchanging with hydrogen ions of terminal hydroxyl groups(Al-OH_(2),Fe-OH_(2)),and/or,hydrated uranyl ions are bound directly to Al(Ⅲ)center in MIL-100(Al)through a strong inner-sphere coordination.For MIL-100(Cr),however,the U(Ⅵ)uptake is attributed to electrostatic attraction.Besides,the sorption mechanism is also pH and ionic strength dependent.The present study suggests that changing metal center of metal–organic frameworks and sorption conditions alters sorption mechanism,which helps to construct effective metal–organic frameworks-based sorbents for water purification.展开更多
2,9-Diamide-1,10-phenanthroline(DAPhen)ligands represent a new family of tetradentate extractants given their strong affinity to actinides and the CHON principle.Among this family,N,N′-diethyl-N,N′-ditolyl-2,9-diami...2,9-Diamide-1,10-phenanthroline(DAPhen)ligands represent a new family of tetradentate extractants given their strong affinity to actinides and the CHON principle.Among this family,N,N′-diethyl-N,N′-ditolyl-2,9-diamide-1,10-phenanthroline(Et-TolDAPhen),initially reported by us,exhibits excellent selectivity towards actinides(U,Th,Am,Pu)over lanthanides and thus can be potentially applied in the group actinide extraction(GANEX)process for the group separation of actinides.In this article,by tailoring the lengths of alkyl chains,we synthesized other four DAPhen ligands with different substitute groups in the diamide moieties,and characterized the relationship between properties and substitute groups of DAPhen ligand.The extraction results show that three of the ligands exhibit high performance in UO_2^(2+)extraction from an acidic solution and the extracted UO_2^(2+)can be easily stripped by only using ultrapure water.Spectrophotometry titration confirms that UO_2^(2+)combined with all the four ligands in 1:1 mode.The extended X-ray absorption finestructure(EXAFS)study shows that six donor atoms comprise the first equatorial shell of the UO_2^(2+)ions bonded by the DAPhen ligands,among which two nitrogen and two oxygen atoms are from the DAPhen ligand,while other two oxygen atoms are from one nitrate ions.This article promises to provide basic data for assessing the feasibility of this kind of DAPhen ligands applied in actinides separation from nuclear wastes.展开更多
γ-ray radiation-induced grafting strategy was first employed to immobilize 4-aminobenzo-15-crown-5 onto a covalent organic framework(COF).This endeavor culminated in the successful synthesis of a class of two-dimensi...γ-ray radiation-induced grafting strategy was first employed to immobilize 4-aminobenzo-15-crown-5 onto a covalent organic framework(COF).This endeavor culminated in the successful synthesis of a class of two-dimensional crown ether-modified COFs(named[15C5]n%-(TzDa-G-x%)),marking the maiden utilization of COFs in the realm of^(6)Li/^(7)Li isotope separation.These COFs exhibited swifter adsorption kinetics than alternative adsorbents.Among them,[15C5]_(57%)-(TzDa-G-50%)with its excellent crystallinity,porosity,and stability exhibited the best performance in Li+adsorption and^(6)Li/^(7)Li isotope separation.The Li+adsorption in acetonitrile achieved a capacity of 3.6 mg·g^(−1)within 30 min and a saturation capacity of 7.3 mg·g^(−1).The single-stage separation factor of^(6)Li/^(7)Li isotopes was 1.014±0.001.The results of dynamic adsorption column experiments showed that the packed column made of[15C5]_(57%)-(TzDa-G-50%)maintained stable performance during four cycles of Li+adsorptionelution,with over 99%Li+removal rate in acetonitrile.This crown ether-modified COF has potential application in^(6)Li/^(7)Li isotope separation,and this radiation-assisted synthesis strategy is expected to become universal in the modification of COFs for diverse applications.展开更多
基金Supported by Technology Research and Development Plan of the Department of Science and Technology in Hebei Province(11220104D-4)
文摘‘Jinxiu' is a processing apricot(Armeniaca vulgaris L.) cultivar derived from the cross of ‘Chuanzhihong'בJintaiyang'.The fruit is oval-shaped with the ground color of orange and 1/4-1/2 sheet red in the surface. The average fruit weight is65.5 g, and the maximum value is 106 g. The flesh is orange, fine with very less fiber, toughness, less juice and freestone, and tastes sour and sweet. The soluble solid content is 12.5%. The edible rate is 95.8%. The fruit skin hardness is 12.9 kg/cm2 and storable. The preserved apricots have orange color and are tasty. The preserved yield is 40%. The fruit development period is 72 d. The fruit has high yield, and the fruit yield in full fruit period can reach 37 000 kg/hm2. ‘Jinxiu' was examined and approved by Hebei Examination and Approval Committee of Forest Tree Variety in 2013.
基金supported by the National Natural Science Foundation of China(Nos.U1967216,22076188,U20B2019,21876174)the National Science Fund for Distinguished Young Scholars(No.21925603).
文摘Uranium and molybdenum are important strategic elements. The production of ^(99)Mo and the hydrometallurgical process of uranium ore face difficult problems of separation of uranium and molybdenum.In this study, the four phenanthroline diamide ligands were synthesized, and extraction and stripping experiments were performed under different conditions to evaluate the potential application of these ligands for separation of U(Ⅵ) over Mo(Ⅵ). With the growth of alkyl chain, the solubility of ligands could be greatly improved, and the separation effect of U(Ⅵ) over Mo(Ⅵ) gradually increased. The SF_(U/Mo) were around 10,000 at 4 mol/L HNO3. Three stripping agents were tested with the stripping efficiency of Na_(2)CO_(3)(5%) > H_(2)O > HNO_(3)(0.01 mol/L). The stripping percentages of the three stripping agents were all close to unity, indicating that the ligands had the potential to be recycled. The chemical stoichiometry of U(Ⅵ) complexes with ligands was evaluated as 1:1 using electrospray ionization mass spectrometry,ultraviolet visible spectroscopy and single-crystal X-ray diffraction. The consistency between theoretical calculation and experimental results further explains the coordination mechanism.
基金supported by the National Natural Science Foundation of China(Grant Nos.22276193,U20B2019,and U2067212)the National Science Fund for Distinguished Young Scholars(Grant No.21925603).
文摘Although mesoporous silica with magnetically hybridized two-dimensional channel structures has been well studied in recent years,it remains a challenge to fabricate the counterpart with macroporous three-dimensional cubic structures since the highly acidic preparation conditions lead to dissolution of magnetic particles.Herein,we successfully prepared magnetic KIT-6 nano-composite and its amino derivatives by bearing acid-resistant iron oxide.The prepared materials exhibited excellent properties for U(VI)ions removal from aqueous solutions under various conditions.The experimental data show that the U(VI)adsorption features fast adsorption kinetics,high adsorption capacity and ideal selectivity toward U(VI).The adsorption process is of spontaneous and endothermic nature and ionic strength independence,and the adsorbents can be easily regenerated by acid treatment.Compared to pristine KIT-6,the introduction of magnetism does not reduce the efficiency of the material to remove U(VI)while exerting its role as a recovery adsorbent.The findings of this work further demonstrate the potential broad application prospects of magnetic hybrid mesoporous silica in radionuclide chelation.
基金supported by the National Natural Science Foundation of China (11275219, 11275090, U1432103)the “Strategic Priority Research program” of the Chinese Academy of Sciences (XDA030104)+1 种基金the State Key Laboratory of NBC Protection for Civilian (SKLNB201412)the Scientific Research Fund of Hunan Provincial Education Department (12A116)
文摘Functionalized magnetic Fe_3O_4@SiO_2 composite nanoparticles were prepared by simply embedding iron oxide nanoparticles into MCM-41 through one-step synthesis process, followed by aminopropyls grafting on the mesopore channels, aiming to efficiently and conveniently uptake U(VI) from aqueous solution. The resultant material possesses highly ordered mesoporous structure with large surface area, uniform pore size, excellent thermal stability, quick magnetic response, and desirable acids resistance, confirmed by Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), N_2 adsorption/desorption experiments, powder X-ray diffraction(PXRD), and thermogravimetric analysis(TGA). Detailed U(VI) sorption test indicated that this material is indeed an effective U(VI) sorbent with fast sorption kinetics of less than 2 h, large sorption capacity of 160 mg/g at p H 5.0±0.1, and desirable selectivity towards U(VI) ions over a range of competing metal ions. The absorbed U(VI) can be easily desorbed by 0.01 mol/L or more concentrated HNO_3 solution, and the reclaimed sorbent can be reused with no obvious decrease of sorption capacity even after 4 sorption-desorption cycles. The present results suggest the vast opportunities of this kind of magnetic composite on the solid-phase extraction of U(VI).
基金supported by the National Natural Science Foundation of China (91426302, 91226201, 91326202)the "Strategic Priority Research Program" of the Chinese Academy of Sciences (XDA030104)
文摘Electrochemical properties of rare-earth elements in the LiCl-KCl eutectic are important for the pyrometallurgical recycling process of spent nuclear fuels. In this work, the electrochemical properties of Tb(Ⅲ)/Tb(0) couple were studied by the cyclic voltammetry(CV) at a liquid Zn pool electrode. The results showed that this electrochemical reaction is quasi-reversible with mixed reversible diffusion control and the charge transfer control. The diffusion coefficient of Tb(Ⅲ) was determined to be in the order of ~10.5 cm2 s.1. Moreover, kinetic parameters, such as the standard rate constants(ks) and charge transfer coefficient(α) for the electroreduction of Tb(Ⅲ) to Tb(0) at the liquid Zn electrode, were calculated by the Nicholson method at 873 K. Additionally, it was found that Tb-Zn intermetallic compounds were easily to be formed in the measurements. Hence, the reduction process of Tb(Ⅲ)/Tb(0) couple on the Zn-coated Mo electrode was also studied to obtain more information of the Tb-Zn intermetallic compounds. Electrochemical signals stemming from various intermetallic compounds associated with TbZn12, Tb2Zn17, Tb13Zn58, Tb3Zn11, TbZn3, TbZn2 and TbZn, were observed. The thermodynamic data were thereafter estimated by applying the emf method at 823–923 K. The standard formation Gibbs energies and the standard equilibrium constant of each Tb-Zn intermetallic compounds were also calculated. Finally, enthalpies and entropies of formation and the apparent standard potentials of various Tb-Zn intermetallic compounds were also obtained.
基金supported by the Major Research Plan"Breeding and Transmutation of Nuclear Fuel in Advanced Nuclear Fission Energy System"of the Natural Science Foundation of China(91426302,91326202,51604252)the National Natural Science Foundation of China(21377122)
文摘This work presents the electrochemical properties of gadolinium(Gd), a significant rare earth element in spent nuclear fuel(SNF), in the LiCl-KCl eutectic. To explore thermodynamic properties of Gd at the liquid gallium(Ga) electrode, experiments were performed both on the inert tungsten(W) and liquid gallium(Ga) electrode at different temperatures in a range from 723 to 823 K, which show that the Gd metal can be oxidized to Gd(Ⅲ) by exchanging of 3 electrons. Electrochemical techniques including cyclic voltammetry(CV), open circuit potential(OCP), potentiostatic electrolysis and galvanostatic electrolysis were utilized to detect the electrochemical behavior and evaluate standard apparent potential of the Gd(Ⅲ)/Gd couple,and E(Gd(Ⅲ)/Gd)*=-3.456 + 6.2×10-4T(±0.046)( vs Cl2/Cl-) is obtained.In addition, electromotive force(EMF) and coulometric titration were employed to calculate the activity and activity coefficient of Gd in metal Ga. After calculation, the activity is 1.791×10-15at 723 K and function of activity coefficient and temperature is lgγ = 3.485-10927/T(±0.0875).
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.21577144,21777161,11575212,and 21806167)the Science Challenge Project(TZ2016004)the Youth Innovation Promotion As-sociation of CAS(2017020).
文摘Although solid-phase extraction is a useful approach for metal ion separation from aqueous solutions,existing sorbents suffer from low extraction effici-encies and/or instability when in contact with strong acidic media.We report here the first study on rational design and fabrication of phosphonate-decorated covalent organic frameworks,COF-IHEP1 and COF-IHEP2,for efficient and selective extraction of of uranium(VI)[U(VI)]and plutonium(IV)[Pu(IV)]from highly acidic solutions.
基金This work was supported by the National Science Fund for Distinguished Young Scholars(No.21925603)the National Natural Science Foundation of China(No.21806167)+1 种基金the Science Challenge Project(TZ2016004)the Youth Inn ovation Promoti on Association of CAS(2017020).
文摘The issue of covale nee of acti nide complexes remai ns con troversial to date.The in troducti on of 2-phosphaethy nolate anion into acti・nide complexes is expected to in vestigate the reaction mode and the bon ding property.Herei n,we describe the function alizatio n of An(Tren^(TIPS))CI(1:An=U;2:An=Th)precursors with NaOCP(dioxane)_(2.5) through salt-elimination method leading to the formation of the corresponding uranium and thorium phosphaethynolate species:[U(Tren^(TIPS))(OCP)]⑶and[Th(Tren^(TIPS))(OCP)](4).
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.U20B2019,21790373 and 21790370)the National Science Fund for Distinguished Young Scholars(Grant No.21925603).
文摘Although metal–organic frameworks offer a new platform for developing versatile sorption materials,yet coordinating the functionality,structure and component of these materials remains a great challenge.It depends on a comprehensive knowledge of a“real sorption mechanism”.Herein,a ternary mechanism for U(Ⅵ)uptake in metal–organic frameworks was reported.Analogous MIL-100s(Al,Fe,Cr)were prepared and studied for their ability to sequestrate U(Ⅵ)from aqueous solutions.As a result,MIL-100(Al)performed the best among the tested materials,and MIL-100(Cr)performed the worst.The nuclear magnetic resonance technique combined with energy-dispersive X-ray spectroscopy and zeta potential measurement reveal that U(Ⅵ)uptake in the three metal–organic frameworks involves different mechanisms.Specifically,hydrated uranyl ions form outer-sphere complexes in the surface of MIL-100s(Al,Fe)by exchanging with hydrogen ions of terminal hydroxyl groups(Al-OH_(2),Fe-OH_(2)),and/or,hydrated uranyl ions are bound directly to Al(Ⅲ)center in MIL-100(Al)through a strong inner-sphere coordination.For MIL-100(Cr),however,the U(Ⅵ)uptake is attributed to electrostatic attraction.Besides,the sorption mechanism is also pH and ionic strength dependent.The present study suggests that changing metal center of metal–organic frameworks and sorption conditions alters sorption mechanism,which helps to construct effective metal–organic frameworks-based sorbents for water purification.
基金supported by the National Natural Science Foundation of China (21471153, 21777161, 21477130, 21790373)the Youth Innovation Promotion Association, Chinese Academy of Sciences and the Science Challenge Project (JCKY2016212A504)
文摘2,9-Diamide-1,10-phenanthroline(DAPhen)ligands represent a new family of tetradentate extractants given their strong affinity to actinides and the CHON principle.Among this family,N,N′-diethyl-N,N′-ditolyl-2,9-diamide-1,10-phenanthroline(Et-TolDAPhen),initially reported by us,exhibits excellent selectivity towards actinides(U,Th,Am,Pu)over lanthanides and thus can be potentially applied in the group actinide extraction(GANEX)process for the group separation of actinides.In this article,by tailoring the lengths of alkyl chains,we synthesized other four DAPhen ligands with different substitute groups in the diamide moieties,and characterized the relationship between properties and substitute groups of DAPhen ligand.The extraction results show that three of the ligands exhibit high performance in UO_2^(2+)extraction from an acidic solution and the extracted UO_2^(2+)can be easily stripped by only using ultrapure water.Spectrophotometry titration confirms that UO_2^(2+)combined with all the four ligands in 1:1 mode.The extended X-ray absorption finestructure(EXAFS)study shows that six donor atoms comprise the first equatorial shell of the UO_2^(2+)ions bonded by the DAPhen ligands,among which two nitrogen and two oxygen atoms are from the DAPhen ligand,while other two oxygen atoms are from one nitrate ions.This article promises to provide basic data for assessing the feasibility of this kind of DAPhen ligands applied in actinides separation from nuclear wastes.
基金the National Natural Science Foundation of China(grant no.U2067212)the National Science Fund for Distinguished Young Scholars(grant no.21925603).
文摘γ-ray radiation-induced grafting strategy was first employed to immobilize 4-aminobenzo-15-crown-5 onto a covalent organic framework(COF).This endeavor culminated in the successful synthesis of a class of two-dimensional crown ether-modified COFs(named[15C5]n%-(TzDa-G-x%)),marking the maiden utilization of COFs in the realm of^(6)Li/^(7)Li isotope separation.These COFs exhibited swifter adsorption kinetics than alternative adsorbents.Among them,[15C5]_(57%)-(TzDa-G-50%)with its excellent crystallinity,porosity,and stability exhibited the best performance in Li+adsorption and^(6)Li/^(7)Li isotope separation.The Li+adsorption in acetonitrile achieved a capacity of 3.6 mg·g^(−1)within 30 min and a saturation capacity of 7.3 mg·g^(−1).The single-stage separation factor of^(6)Li/^(7)Li isotopes was 1.014±0.001.The results of dynamic adsorption column experiments showed that the packed column made of[15C5]_(57%)-(TzDa-G-50%)maintained stable performance during four cycles of Li+adsorptionelution,with over 99%Li+removal rate in acetonitrile.This crown ether-modified COF has potential application in^(6)Li/^(7)Li isotope separation,and this radiation-assisted synthesis strategy is expected to become universal in the modification of COFs for diverse applications.
