N,N,N',N'-tetraoctyl diglycolamide(TODGA)is a potential extractant for the co-extraction of lanthanides and actinides in high-level liquid waste.In this study,the radiolysis and extraction properties of TODGA ...N,N,N',N'-tetraoctyl diglycolamide(TODGA)is a potential extractant for the co-extraction of lanthanides and actinides in high-level liquid waste.In this study,the radiolysis and extraction properties of TODGA in kerosene solvents contacted with the aqueous phase of varying HNO_(3) concentrations were systematically investigated,and the complexation mechanism was analyzed in conjunction with density functional theory(DFT)calculations.After γ-irradiation,the variation of TODGA concentration was detected,and the variation trends in the relative content of radiolysis products(RPs)with sample type and absorbed dose were demonstrated.Results indicated that the breaking of the amide bond,ether bond,and C_(amide)-C_(ether)bond was the primary radiolysis routes.The aqueous-phase precipitate was studied as a potential new mode of TODGA radiolysis in ultrapure water aqueous phase.Moreover,TODGA/kerosene exhibited excellent extraction capabilities for lanthanides even after absorbing 100 kGy,and HNO_(3) can maintain a portion of TODGA's extraction capacity.The DFT method was applied to calculate and evaluate the complexing ability of TODGA and some of its RPs toward lanthanides.The results revealed that the complexing ability of TODGA for Ce(Ⅲ),Eu(Ⅲ),and Dy(Ⅲ)was enhanced successively,and the complexing ability of the RPs with intact oxygen-containing structures could not be neglected.展开更多
The unique physical and chemical properties of rare earth elements lay the foundation for their extensive application. N,N,N’,N’ Tetra-octyl-3-oxopentanediamide(TODGA) is excellent in its ability of extracting rare ...The unique physical and chemical properties of rare earth elements lay the foundation for their extensive application. N,N,N’,N’ Tetra-octyl-3-oxopentanediamide(TODGA) is excellent in its ability of extracting rare earth elements and it is favored for green initiative. In this paper, the extraction and back-extraction of14 rare earth elements by TODGA were studied. Experiments show that in conditions of 6 mol/L sulfuric acid, the extraction temperature of 25 ℃,the phase ratio of 1:1 and 0.04 mol/LTODGA(aviation kerosene as the diluent), the extraction rates of 14 rare earth elements including lanthanum, cerium, praseodymium,neodymium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and yttrium were 99.00%-99.73%. Mixed with hydrochloric acid and nitric acid(HCl 3.5 mol/L, HNO30.5 mol/L), the recoveries of the 14 rare earth elements are 91.52%-99.91% when the extraction temperature is 25 ℃ and the ratio is 1:1. The following application is based on the optimum conditions above with practical samples(from the roasting production line of China North Rare Earth High-tech Company Limited) for extraction and back-extraction experiments. Experiments show that TODGA has excellent enrichment effect on 14 rare earth elements, the extraction rates are 91.36%-99.80%, the back-extraction rates are 87.29%-99.64% and the total recoveries are 81.19%-99.44%.展开更多
N,N,N′,N′-Tetraoctyl diglycolamide(TODGA)is one of the most promising extractants tailored for high-level liquid radioactive waste treatment during nuclear fuel reprocessing.Theγ-radiolysis of TODGA(0.2 mol/L)in n-...N,N,N′,N′-Tetraoctyl diglycolamide(TODGA)is one of the most promising extractants tailored for high-level liquid radioactive waste treatment during nuclear fuel reprocessing.Theγ-radiolysis of TODGA(0.2 mol/L)in n-dodecane(n DD)solution with and without pre-equilibrated 3.0 mol/L HNO_(3)was investigated using HPLC and UPLC-QTOF-MS and compared with theγ-radiolysis of neat TODGA in this study.With increased absorbed doses,the concentration of TODGA decreased exponentially for the studied systems.Moreover,pre-equilibration with HNO_(3)(3.0 mol/L)slightly influenced theγ-radiolysis of TODGA in n DD.Seven radiolytic products generated from the rupture of the C–C,C–O,and C–N bonds in TODGA were identified in the studied extraction system.The influence ofγ-radiation on TODGA/n DD for the extraction of Eu(Ⅲ)was evaluated using the first combination of extraction experiments and density functional theory(DFT)calculations,in which the complexations of Eu(Ⅲ)with TODGA and its radiolytic products were systematically compared.Based on the radiolysis kinetic model of TODGA,the slope curve of the distribution ratio of Eu(Ⅲ)(D_(Eu))and the absorbed dose,and fluorescence titration analysis,the empirical equation of the absorbed dose and D_(Eu)was obtained successfully.Below 300 kGy,the experimental D_(Eu)agreed well with the obtained empirical equation for TODGA/n DD.Conversely,at a high absorbed dose,the experimental D_(Eu)was higher than the theoretical D_(Eu)based on the empirical equation because the radiolytic products of TODGA with similar coordination structures still possessed partial complexation toward Eu(Ⅲ),which was confirmed by DFT calculations.This work provides a method to predict the extraction distribution ratio of an irradiated extractant system and to understand the complex extraction process.展开更多
通过改进岩石样品分析物Nd的化学分离,实现Nd同位素比值的准确分析,为研究青藏高原岩石成因,揭示物质来源提供技术支持。采用TODGA萃淋树脂分离基体及其与Nd相邻的稀土元素,用多接收电感耦合等离子体质谱(MC-ICP-MS)法测定Nd同位素比值...通过改进岩石样品分析物Nd的化学分离,实现Nd同位素比值的准确分析,为研究青藏高原岩石成因,揭示物质来源提供技术支持。采用TODGA萃淋树脂分离基体及其与Nd相邻的稀土元素,用多接收电感耦合等离子体质谱(MC-ICP-MS)法测定Nd同位素比值,建立了简捷实用的地质样品中Nd同位素分析方法。样品经HF-HNO_(3)分解,HNO_(3)(3 mol/L)-H_(3)BO_(3)(0.12 mol/L)提取,上柱后,先用6 mL HCl(2.8 mol/L)淋洗干扰轻稀土,再用6 mL HCl(2.2 mol/L)淋洗分析物Nd,Nd淋洗液由MC-ICP-MS测定其同位素比值。分析国际岩石标准物质BCR-2、BHVO-2和AGV-2,所得^(143)Nd/^(144)Nd同位素比值(平均值±2σ)分别为0.512638±0.000007、0.512990±0.0000012和0.512792±0.000016,这些同位素数据在误差范围内,与推荐值和文献值完全一致。方法适合各种类型地质样品,为西藏不同地区不同岩石提供了可靠的Nd同位素分析数据。展开更多
文摘N,N,N',N'-tetraoctyl diglycolamide(TODGA)is a potential extractant for the co-extraction of lanthanides and actinides in high-level liquid waste.In this study,the radiolysis and extraction properties of TODGA in kerosene solvents contacted with the aqueous phase of varying HNO_(3) concentrations were systematically investigated,and the complexation mechanism was analyzed in conjunction with density functional theory(DFT)calculations.After γ-irradiation,the variation of TODGA concentration was detected,and the variation trends in the relative content of radiolysis products(RPs)with sample type and absorbed dose were demonstrated.Results indicated that the breaking of the amide bond,ether bond,and C_(amide)-C_(ether)bond was the primary radiolysis routes.The aqueous-phase precipitate was studied as a potential new mode of TODGA radiolysis in ultrapure water aqueous phase.Moreover,TODGA/kerosene exhibited excellent extraction capabilities for lanthanides even after absorbing 100 kGy,and HNO_(3) can maintain a portion of TODGA's extraction capacity.The DFT method was applied to calculate and evaluate the complexing ability of TODGA and some of its RPs toward lanthanides.The results revealed that the complexing ability of TODGA for Ce(Ⅲ),Eu(Ⅲ),and Dy(Ⅲ)was enhanced successively,and the complexing ability of the RPs with intact oxygen-containing structures could not be neglected.
基金supported by Beijing Natural Science Foundation(8172033)Fundamental Research Funds for the Central Universities of China(FRF-BR-15-015A)
文摘The unique physical and chemical properties of rare earth elements lay the foundation for their extensive application. N,N,N’,N’ Tetra-octyl-3-oxopentanediamide(TODGA) is excellent in its ability of extracting rare earth elements and it is favored for green initiative. In this paper, the extraction and back-extraction of14 rare earth elements by TODGA were studied. Experiments show that in conditions of 6 mol/L sulfuric acid, the extraction temperature of 25 ℃,the phase ratio of 1:1 and 0.04 mol/LTODGA(aviation kerosene as the diluent), the extraction rates of 14 rare earth elements including lanthanum, cerium, praseodymium,neodymium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and yttrium were 99.00%-99.73%. Mixed with hydrochloric acid and nitric acid(HCl 3.5 mol/L, HNO30.5 mol/L), the recoveries of the 14 rare earth elements are 91.52%-99.91% when the extraction temperature is 25 ℃ and the ratio is 1:1. The following application is based on the optimum conditions above with practical samples(from the roasting production line of China North Rare Earth High-tech Company Limited) for extraction and back-extraction experiments. Experiments show that TODGA has excellent enrichment effect on 14 rare earth elements, the extraction rates are 91.36%-99.80%, the back-extraction rates are 87.29%-99.64% and the total recoveries are 81.19%-99.44%.
文摘N,N,N′,N′-Tetraoctyl diglycolamide(TODGA)is one of the most promising extractants tailored for high-level liquid radioactive waste treatment during nuclear fuel reprocessing.Theγ-radiolysis of TODGA(0.2 mol/L)in n-dodecane(n DD)solution with and without pre-equilibrated 3.0 mol/L HNO_(3)was investigated using HPLC and UPLC-QTOF-MS and compared with theγ-radiolysis of neat TODGA in this study.With increased absorbed doses,the concentration of TODGA decreased exponentially for the studied systems.Moreover,pre-equilibration with HNO_(3)(3.0 mol/L)slightly influenced theγ-radiolysis of TODGA in n DD.Seven radiolytic products generated from the rupture of the C–C,C–O,and C–N bonds in TODGA were identified in the studied extraction system.The influence ofγ-radiation on TODGA/n DD for the extraction of Eu(Ⅲ)was evaluated using the first combination of extraction experiments and density functional theory(DFT)calculations,in which the complexations of Eu(Ⅲ)with TODGA and its radiolytic products were systematically compared.Based on the radiolysis kinetic model of TODGA,the slope curve of the distribution ratio of Eu(Ⅲ)(D_(Eu))and the absorbed dose,and fluorescence titration analysis,the empirical equation of the absorbed dose and D_(Eu)was obtained successfully.Below 300 kGy,the experimental D_(Eu)agreed well with the obtained empirical equation for TODGA/n DD.Conversely,at a high absorbed dose,the experimental D_(Eu)was higher than the theoretical D_(Eu)based on the empirical equation because the radiolytic products of TODGA with similar coordination structures still possessed partial complexation toward Eu(Ⅲ),which was confirmed by DFT calculations.This work provides a method to predict the extraction distribution ratio of an irradiated extractant system and to understand the complex extraction process.
文摘通过改进岩石样品分析物Nd的化学分离,实现Nd同位素比值的准确分析,为研究青藏高原岩石成因,揭示物质来源提供技术支持。采用TODGA萃淋树脂分离基体及其与Nd相邻的稀土元素,用多接收电感耦合等离子体质谱(MC-ICP-MS)法测定Nd同位素比值,建立了简捷实用的地质样品中Nd同位素分析方法。样品经HF-HNO_(3)分解,HNO_(3)(3 mol/L)-H_(3)BO_(3)(0.12 mol/L)提取,上柱后,先用6 mL HCl(2.8 mol/L)淋洗干扰轻稀土,再用6 mL HCl(2.2 mol/L)淋洗分析物Nd,Nd淋洗液由MC-ICP-MS测定其同位素比值。分析国际岩石标准物质BCR-2、BHVO-2和AGV-2,所得^(143)Nd/^(144)Nd同位素比值(平均值±2σ)分别为0.512638±0.000007、0.512990±0.0000012和0.512792±0.000016,这些同位素数据在误差范围内,与推荐值和文献值完全一致。方法适合各种类型地质样品,为西藏不同地区不同岩石提供了可靠的Nd同位素分析数据。
