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Theoretical elucidation of rare earth extraction and separation by diglycolamides from crystal structures and DFT simulations 被引量:1
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作者 Xiujing Peng Jianhui Su +3 位作者 Hao Li Yu Cui Jin Yong Lee Guoxin Sun 《Journal of Rare Earths》 SCIE EI CAS CSCD 2021年第7期858-865,I0004,共9页
Diglycolamides(DGAs) show excellent application prospects for the extraction and separation of rare earth metals from highly radioactive liquid wastes and rare earth ores.The extraction ability of DGAs for rare earth ... Diglycolamides(DGAs) show excellent application prospects for the extraction and separation of rare earth metals from highly radioactive liquid wastes and rare earth ores.The extraction ability of DGAs for rare earth ions in nitrate or chloride media increases with increasing atomic number of the rare earth metal.To understand the origin of this phenomenon,three binuclear crystals [Ln(TEDGA)_(3)][Ln(NO_(3))_(6)] of N,N,N’,N’-tetraethyldiglycolamide(TEDGA) with rare earth ions La(Ⅲ),Pr(Ⅲ) and Eu(III) were prepared and characterized crystallographically.The three complexes belong to the triclinic crystal system,P-1 space group.The bond lengths of Ln-O_(amide) are significantly shorter than those of Ln-O_(ether) in the same crystal.The Ln-O_(amide) and Ln-O_(enher) bond lengths gradually decrease with increasing atomic number of the rare earth ion.The dihedral angle formed by TEDGA and metal ions through the tridentate coordination gradually increases with increasing metal ion atomic number,tending toward the formation of sizeable planar coordination structures for the most massive rare earth ions.The structures of the compounds formed by the extractant and metal ion were optimized by means of DFT simulations.We find that the interaction between TEDGA and the rare earth ion is dominated by electrostatic interaction by analyzing binding energy,WBIs,Mulliken charge,natural electron configurations,and molecular orbital interaction.The covalent component of the Ln-O bonds of the complexes increases with increasing metal atomic number.The observed increase in extraction and separation capacity of diglycolamides for rare earth ions with increasing atomic number might be due to the formation of two fivemember rings by one tridentate ligand.The rare earth ions with large atomic numbers tend to form planar structures with large dihedral angles with DGA ligands. 展开更多
关键词 DIGLYCOLAMIDE Extraction Separation Rare earth Crystal structures DFT simulations
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Adsorption of Er(Ⅲ ) and Its Mechanism on Diglycolamidic Acid Resin 被引量:14
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作者 熊春华 沈秋仙 《Journal of Rare Earths》 SCIE EI CAS CSCD 2002年第5期492-496,共5页
The adsorption behavior and mechanism of a novel chelate resin, diglycolamidic acid resin (DAAR) for Er(Ⅲ) were investigated. The optima adsorption condition of DAAR for Er(Ⅲ) is pH 6.20 in HAc NaAc medium. The sta... The adsorption behavior and mechanism of a novel chelate resin, diglycolamidic acid resin (DAAR) for Er(Ⅲ) were investigated. The optima adsorption condition of DAAR for Er(Ⅲ) is pH 6.20 in HAc NaAc medium. The statically saturated adsorption capacity is 189 mg·g -1 resin at 298 K. The Er (Ⅲ) adsorbed on DAAR can be eluted reaching 100% by 2 mol·L -1 HCl used as eluant. The resin can be regenerated and reused without apparent decreasing of adsorption capacity. The apparent adsorption rate constant is k 298 =1.94×10 -5 s -1 . The apparent activation energy is 24.7 kJ·mol -1 . The adsorption behavior of DAAR for Er(Ⅲ) obeys the Freundlich isotherm. The thermodynamic adsorption parameters, enthalpy change Δ H of DAAR for Er(Ⅲ) is 24.1 kJ·mol -1 . The molar coordination ratio of the functional group of DAAR to Er (Ⅲ) is 3∶1. The adsorption mechanism of DAAR for Er (Ⅲ) was examined by using chemical method and IR spectrometry. The coordination compound is formed between oxygen atoms in the functional group of DAAR and Er(Ⅲ). 展开更多
关键词 rare earths diglycolamidic acid resin ERBIUM sorption mechanism
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ADSORPTION OF SAMARIUM(III) ON DIGLYCOLAMIDIC ACID RESIN 被引量:6
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作者 SHI Linmei XIONG Chunhua MO Jianjun 《Chinese Journal of Reactive Polymers》 2003年第1期70-77,共8页
The sorption behavior and mechanism of a novel chelate resin, diglycolamidic acid resin (DAAR), for Sm(III) were investigated. The optimal sorption condition of DAAR for Sm(III) is pH=6.0 in HAc-NaAc medium. The stati... The sorption behavior and mechanism of a novel chelate resin, diglycolamidic acid resin (DAAR), for Sm(III) were investigated. The optimal sorption condition of DAAR for Sm(III) is pH=6.0 in HAc-NaAc medium. The statically saturated sorption capacity is 190mg/g resin at 298K. The Sm(III) adsorbed on DAAR can be eluted reaching 100% by 0.5~2.0mol/L HCl used as eluant. The resin can be regenerated and reused without apparent decrease of sorption capacity. The apparent sorption rate constant is k298= 1.96×10-5s-1. The apparent activation energy is 26kJ/mol. The sorption behavior of DAAR for Sm(III) obeys the Freundlich isotherm. The thermodynamic sorption parameters, enthalpy change 腍 of DAAR for Sm(III) is 16.9kJ/mol. The molar coordination ratio of the functional group of DAAR to Sm (III) is 3. The sorption mechanism of DAAR for Sm(III) was examined by using chemical method and IR spectrometry. The coordination bond was formed between oxygen atoms in the functional group of DAAR and Sm(III). 展开更多
关键词 Diglycolamidic acid resin SAMARIUM Sorption mechanism
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Extraction and separation of Nd(Ⅲ), Sm(Ⅲ), Dy(Ⅲ), Fe(Ⅲ), Ni(Ⅱ), and Cs(Ⅰ) from concentrated chloride solutions with N,N,N',N'-tetra(2-ethylhexyl) diglycolamide as new extractant 被引量:8
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作者 E.A.Mowafy D.Mohamed 《Journal of Rare Earths》 SCIE EI CAS CSCD 2015年第4期432-438,共7页
The feasibility of using N,N,N',N'-tetra(2-ethylhexyl)diglycolamide (TEHDGA) in 75 vol.% n-dodecane-25 vol.% n-octanol as agents for the extraction and separation ofNd(III), Sm(III), Dy(llI), Fe(III), Ni... The feasibility of using N,N,N',N'-tetra(2-ethylhexyl)diglycolamide (TEHDGA) in 75 vol.% n-dodecane-25 vol.% n-octanol as agents for the extraction and separation ofNd(III), Sm(III), Dy(llI), Fe(III), Ni(II), and Cs(I) from concentrated chlo- ride solution was investigated. Different extraction behaviors were obtained towards rare earth elements (REE) studied and Fe(IIl), Ni(II) and Cs(I). Efficient separation of Nd(III), Sm(III) and Dy(III) from Fe(III), Ni(II), and Cs(I) was achieved by TEHDGA, depending on the HCI, HNO3 or H2SO4 concentration. A systematic investigation was carried out on the detailed extraction prop- erties of Nd(III), Sm(III), and Dy(III) with TEHDGA from chloride media. The IR spectra of the extracted species were investi- gated. 展开更多
关键词 DIGLYCOLAMIDE extraction REE and base metals ions chloride medium rare earths
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New’Non-phosphorous’and Efficient Diglycolamide-acid Based Extraction Systems 被引量:1
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作者 ZHANG Yang ZHAO Zhi-Gang +6 位作者 XIE Mei-Ying XUE Li-Yan YU Shu-Wen JIANG Zheng-Ming SHAO Zhi-Heng WANG Kai-Xian YANG Fan 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2020年第12期2139-2147,2055,共10页
In this paper,we briefly reviewed the new non-phosphorous extraction systems proposed according to the different applicational ends.These systems were established by choosing the suitably modified chemical group and t... In this paper,we briefly reviewed the new non-phosphorous extraction systems proposed according to the different applicational ends.These systems were established by choosing the suitably modified chemical group and the corresponding substrate with unique chemical/physical properties.The guiding principle for the foundation of these new systems was to combine the advantages of the substrate and functions of the modified chemical group,majorly the diglycolamide-acid.The induced physical/chemical properties of the substrate and the functions of modified moieties had the potential to import unique traits to the as-founded adsorbent,establishing a task-tailored bi-/multi-functional system.We believe the new systems had the potential to create new adsorption/desorption extraction/bask-extraction paradigms to improve the selectivity and capacity of the extraction/adsorption process,as well as to be more time-efficient and environmentally friendly. 展开更多
关键词 EXTRACTION ADSORPTION/DESORPTION diglycolamide acid MODIFICATION
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