Speciation of lanthanide ions in the organic phase after extraction from nitrate media by basic extractants

Onghena, Bieke; Papagni, Eleonora; Souza, Ernesto Rezende; Banerjee, Dipanjan; Binnemans, Koen; Hoogerstraete, Tom Vander

doi:10.1039/c8ra06712k

Cited by 41 publications

(64 citation statements)

References 47 publications

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“…13,17 Solvent extraction of lanthanides with Aliquat 336 (a quaternary ammonium) shows decreasing distribution ratio with atomic number when extracted from a NO3medium, and the reverse when extracted from a SCNmedium. 13 The decreasing trend with NO3background is unique and cannot be explained by either electrostatic effects or steric arguments, 18 although electrostatic interactions between TOMA and anionic complexes of lanthanides are implicated in this process. 19 Aggregation of extractants has been hypothesized to influence the extraction trends and anion effects in the case of Aliquat 336.…”

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confidence: 99%

Ion-specific clustering of metal–amphiphile complexes in rare earth separations

2020

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confidence: 99%

Ion-specific clustering of metal–amphiphile complexes in rare earth separations

2020

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“…Likewise to the extraction study, stripping is equally significant for regeneration of adopted extractant in the process and so as the enrichment of extracted metal into the stripped solution for achieving its clean separation. There are several in organic-acids, alkalis and salts are employed for stripping of REEs from the loaded-organic phase [36][37][38][39][40] , but these regents have less stripping ability even at higher concentration level. To overcome such issue and to attain quick regeneration of extractant organic green reagents like oxalic acid is preferred as suitable reagent.…”

Section: Mccabe-thiele Diagrams Of Rees Extractionmentioning

confidence: 99%

Environmentally friendly comprehensive hydrometallurgical method development for neodymium recovery from mixed rare earth aqueous solutions using organo-phosphorus derivatives

Ruiz

Kuchi

Parhi

et al. 2020

Sci Rep

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Rare earth elements (REEs) have obtained a greatest significant in human lives owing to their important roles in various high technology applications. The present method development was deal technology important REEs such as neodymium, terbium and dysprosium, selective extraction with possible separation and recovery studies, successfully. The chloride mediated mixed aqueous solution containing 1500 mg/L each of REEs such as Nd, Tb and Dy was subjected at selective separation of Nd from other associated REEs. Three organo-phosphorous based commercial extracting agents such as Cyanex 272, PC 88A and D2EHPA, were employed for the extraction, possible separation and recovery of rare earth elements. A comparative extraction behavior of all these three extractants as function of time, pH influence, extractant concentration, temperature and diluents were systematically investigated. The extraction tendency of organo-phosphorus reagents towards the extraction of either of the REEs follows of the sequence as: D2EHPA > PC 88A > Cyanex 272. The thermodynamic behavior of either of the extractants on liquid–liquid extraction processing of REEs was investigated and thermodynamic calculations were calculated and presented. Substantial recovery of neodymium oxalate followed by its calcined product as neodymium oxide was ascertained from XRD study and SEM–EDS analysis.

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“…In the NO3case, since the interfacial water structure (and hence hydration) appears to be unaffected by NO3 -, lighter lanthanides which have lower enthalpy of hydration would be better extracted. Interestingly, although the extraction studies show the formation of anionic lanthanide species in the organic phase, 17,18 it is not known whether they form in the aqueous phase, or at the interface, or only in the organic phase. Only positively charged lanthanide species have been reported in aqueous NO3and SCNmedia.…”

Section: Materials Methyltrioctylammonium Chloride (Toma-cl) Lanthamentioning

confidence: 99%

“…12,16 Solvent extraction of lanthanides with Aliquat 336 (a quaternary ammonium) shows decreasing distribution ratio with atomic number when extracted from a NO3medium, and the reverse when extracted from a SCNmedium. 12 The decreasing trend with NO3background is unique and cannot be explained by either electrostatic effects or steric arguments, 17 although electrostatic interactions between TOMA and anionic complexes of lanthanides are implicated in this process. 18 Aggregation of extractants has been hypothesized to influence the extraction trends and anion effects in the case of Aliquat 336.…”

mentioning

confidence: 99%

“…19 The salting-out effect in the aqueous phase also plays a role in determining the organic phase speciation and extraction efficiency. 17,[19][20][21] Further, it has been suggested that in both SCNand NO3cases, aggregates of Aliquat 336 extract the lanthanide rather than single extractant molecules. 19 However, the aggregation structure in these systems has not been characterized.…”

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confidence: 99%

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Ion-Specific Clustering of Metal-Amphiphile Complexes in Rare Earth Separations

Nayak¹,

Lovering²,

Uysal³

2020

Preprint

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<p>The nanoscale structure of a complex fluid can play a major role in the selective adsorption of ions at the nanometric interfaces, which are crucial in industrial and technological applications. Here we study the effect of anions and lanthanide ions on the nanoscale structure of a complex fluid formed by metal-amphiphile complexes, using small angle X-ray scattering. The nano- and mesoscale structures we observe can be directly connected to preferential transfer of light (La, Nd) or heavy (Er, Lu) lanthanides into the complex fluid from an aqueous solution. While the toluene-based complex fluids containing trioctylmethylammonium-nitrate (TOMA-nitrate) always show the same mesoscale hierarchical structure regardless of lanthanide loading and prefer light lanthanides, those containing TOMA-thiocyanate show an evolution of mesoscale structure as a function of the lanthanide loading and prefer heavy lanthanides. The hierarchical structuring indicates the presence of attractive interactions between ion-amphiphile aggregates, causing them to form clusters. A clustering model, that accounts for the hard sphere repulsions and short-range attractions between the aggregates, has been developed to model the X-ray scattering results. The new model successfully describes the nanoscale structure and helps in understanding the mechanisms responsible for amphiphile assisted ion transport between immiscible liquids. Accordingly, our results imply different mechanisms of lanthanide transport depending on the anion present in the complex fluid and correspond with anion-dependent trends in rare-earth separations. </p>

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Speciation of lanthanide ions in the organic phase after extraction from nitrate media by basic extractants

Abstract: Lanthanides are extracted to basic nitrate-based extractants, like trihexyl(tetradecyl)phosphonium nitrate, as pentanitrato lanthanide complexes.

Cited by 41 publications

References 47 publications

Ion-specific clustering of metal–amphiphile complexes in rare earth separations

Ion-specific clustering of metal–amphiphile complexes in rare earth separations

Environmentally friendly comprehensive hydrometallurgical method development for neodymium recovery from mixed rare earth aqueous solutions using organo-phosphorus derivatives

Ion-Specific Clustering of Metal-Amphiphile Complexes in Rare Earth Separations

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