Separation of neodymium and dysprosium by forming coordination polymers

Tasaki-Handa, Yuiko; Abe, Yukie; Ooi, Kenta; Narita, Hirokazu; Tanaka, Mikiya; Wakisaka, Akihiro

doi:10.1016/j.seppur.2015.11.038

Cited by 17 publications

(15 citation statements)

References 31 publications

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“…In addition to any influence of electrolyte viscosity, changes in speciation as a function of Nd(TFSI) 3 concentration could also be responsible for the different electrochemical behaviors. For example, the formation of coordination polymers of lanthanides in the presence of some ligands 31 and in the case of high concentrations of Ti(II) has been reported, 32 leading to the slow diffusion of the polymeric complexes and significantly affecting the current density. Therefore, the formation of such low mobility, large aggregates could be a possibility here, as a result of the large coordination number of neodymium (between 8 and 9).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Correlating Electrochemical Behavior and Speciation in Neodymium Ionic Liquid Electrolyte Mixtures in the Presence of Water

Sanchez-Cupido

Pringle

Siriwardana

et al. 2020

ACS Sustainable Chem. Eng.

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Electrodeposition of rare earth metals at moderate temperature as a means to recover these critical materials from spent magnets or electric motors would be a major breakthrough to close the loop using a sustainable approach. This work highlights that neodymium electrodeposition in a phosphonium-based ionic liquid requires the presence of water in order to achieve a continuous layer of metal deposition. Herein, we describe that the nature of the Nd3+ solvation sphere being composed of both bis(trifluoromethylsulfonyl)imide (TFSI) and water determines neodymium deposition and that this process is not entirely dependent on the physicochemical properties of the electrolyte. The importance of the concentration of neodymium salt for the electrodeposition process has also been investigated, showing that 0.1 mol/kg Nd(TFSI)3/[P66614][TFSI] with 0.4 wt % water is the most promising electrolyte investigated, giving a favorable Nd3+ reduction process and better quality deposits.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Correlating Electrochemical Behavior and Speciation in Neodymium Ionic Liquid Electrolyte Mixtures in the Presence of Water

Sanchez-Cupido

Pringle

Siriwardana

et al. 2020

ACS Sustainable Chem. Eng.

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“…Thus, we were able to obtain higher SF(Dy/Nd) values compared with earlier studies using equivalent framework ion exchange 46 and fraction precipitation by organophosphoric acids. 10 , 26 , 27 …”

Section: Results and Discussionmentioning

confidence: 99%

Intralanthanide Separation on Layered Titanium(IV) Organophosphate Materials via a Selective Transmetalation Process

Zhang

Hietala

Khriachtchev

et al. 2018

ACS Appl. Mater. Interfaces

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The lanthanides (Ln) are an essential part of many advanced technologies. Our societal transformation toward renewable energy drives their ever-growing demand. The similar chemical properties of the Ln pose fundamental difficulties in separating them from each other, yet high purity elements are crucial for specific applications. Here, we propose an intralanthanide separation method utilizing a group of titanium(IV) butyl phosphate coordination polymers as solid-phase extractants. These materials are characterized, and they contain layered structures directed by the hydrophobic interaction of the alkyl chains. The selective Ln uptake results from the transmetalation reaction (framework metal cation exchange), where the titanium(IV) serves as sacrificial coordination centers. The “tetrad effect” is observed from a dilute Ln3+ mixture. However, smaller Ln3+ ions are preferentially extracted in competitive binary separation models between adjacent Ln pairs. The intralanthanide ion-exchange selectivity arises synergistically from the coordination and steric strain preferences, both of which follow the reversed Ln contraction order. A one-step aqueous separation of neodymium (Nd) and dysprosium (Dy) is quantitatively achievable by simply controlling the solution pH in a batch mode, translating into a separation factor of greater than 2000 and 99.1% molar purity of Dy in the solid phase. Coordination polymers provide a versatile platform for further exploring selective Ln separation processes via the transmetalation process.

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“…Another effect can be related to a change in the speciation at high concentrations of Nd(TFSI) 3 . For example, the formation of coordination polymers of lanthanides in the presence of some ligands and in the case of Ti(II) at high concentrations has been reported, producing a decrease in the current density due to a decrease in the diffusion coefficient of the polymeric complexes. We also cannot eliminate the importance of metal speciation on the electrochemical behavior of the metal; a well-known example of this effect can be seen in the electrodeposition of aluminum from solutions of AlCl 4 – compared with Al 2 Cl 7 – from molten salts or ILs. , …”

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confidence: 99%

Water-Facilitated Electrodeposition of Neodymium in a Phosphonium-Based Ionic Liquid

Sanchez-Cupido

Pringle

Siriwardana

et al. 2019

J. Phys. Chem. Lett.

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Rare-earth metals are considered critical metals due to their extensive use in energy-related applications such as wind turbines and nickel−metal hybrid batteries found in hybrid electrical vehicles. A key drawback of the current processing methods includes the generation of large amounts of toxic and radioactive waste. Thus the efficient recovery of these valuable metals as well as cleaner processing methods are becoming increasingly important.Here we report on a clean electrochemical route for neodymium (Nd) recovery from [P 6,6,6,14 ][TFSI], trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)amide which is amplified three times by the presence of water, as evidenced by the cathodic current density and thicker deposits. The role of Nd salt concentrations and water content as an additive in the electrochemistry of Nd 3+ in [P 6,6,6,14 ][TFSI] has been studied. The presence of metallic neodymium in the deposits has been confirmed by X-ray photoelectron spectroscopy.

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Separation of neodymium and dysprosium by forming coordination polymers

Cited by 17 publications

References 31 publications

Correlating Electrochemical Behavior and Speciation in Neodymium Ionic Liquid Electrolyte Mixtures in the Presence of Water

Correlating Electrochemical Behavior and Speciation in Neodymium Ionic Liquid Electrolyte Mixtures in the Presence of Water

Intralanthanide Separation on Layered Titanium(IV) Organophosphate Materials via a Selective Transmetalation Process

Water-Facilitated Electrodeposition of Neodymium in a Phosphonium-Based Ionic Liquid

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