Determination of the Distribution of Cupric Chloro-Complexes in Hydrochloric Acid Solutions at 298 K

Uchikoshi, Masahito

doi:10.1007/s10953-017-0597-8

Cited by 13 publications

(5 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Nevertheless, a full speciation profile and the UV–vis absorption spectra of each of the Cu(II) species can be deduced using the statistical/mathematical techniques principal component analysis (PCA) and multivariate curve resolution-alternative least squares (MCR-ALS). , The mole fractions of the different Cu(II) species as a function of the HCl concentrations, as obtained from the PCA-MCR-ALS analysis of the UV–vis absorption spectra, can be found in Figure . The calculated spectra (see the Supporting Information) and speciation profile are consistent with models, theoretical calculations, X-ray absorption data, and UV–vis absorption analysis reported by other authors. ,− Also, the distribution ratio of Cu(II) for extraction from HCl media toward 0.2 mol L –1 TOMAC in toluene is given in Figure , to enable a comparison between the speciation and the extraction of Cu(II).…”

Section: Results and Discussionsupporting

confidence: 86%

“…They concluded that an anion exchange mechanism for adsorption on resins was correct, although significant adsorption was already found when only very low concentrations of anionic species were present. 19,20 Also, no explanation for the decreasing adsorption efficiency at high HCl concentrations could be given. Onghena et al 21 and Vander Hoogerstraete et al 22 investigated the speciation of trivalent lanthanide ions in solvent extraction systems and concluded that the speciations in the aqueous and organic phase are different.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Model for Metal Extraction from Chloride Media with Basic Extractants: A Coordination Chemistry Approach

et al. 2019

View full text Add to dashboard Cite

The metal extraction mechanism of basic extractants is typically described as an anion exchange process, but this mechanism does not correctly explain all observations. This paper introduces a novel model for the extraction of metals by basic extractants from chloride media supported by experimental data on methyltrioctylammonium chloride and Aliquat 336 chloride systems. This model relies on the hypothesis that the metal species least stabilized in the aqueous phase by hydration (i.e., the metal species with the lowest charge density) is extracted more efficiently than the more water stabilized species (i.e., species with higher charge densities). Once it is transferred to the organic phase, the extracted species can undergo further Lewis acid−base adduct formation reactions with the chloride anions available in the organic phase to form negatively charged chloro complexes, which than associate with the organic cations. Salting-out agents influence the extraction, most likely by decreasing the concentration of free water molecules, which destabilizes the metal complex in the aqueous phase. The evidence provided includes (1) the link between extraction and transition-metal speciation, (2) the trend in extraction efficiency as a function of the concentration of different salting-out agents, and (3) the behavior of HCl in the extraction system. The proposed extraction model better explains the experimental observations in comparison to the anion exchange model and allows the prediction of optimal conditions for metal extractions and separations a priori, by selecting the most suitable salting-out agent and its concentration.

show abstract

Section: Results and Discussionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Model for Metal Extraction from Chloride Media with Basic Extractants: A Coordination Chemistry Approach

et al. 2019

View full text Add to dashboard Cite

show abstract

“…It can be expected that the speciation profile of Zn(II) in other alkali chloride salts and HCl is similar based on previous studies on Co(II)–chloride and Cu(II)–chloride speciation. 9 , 52 , 53 The most efficient extraction of Zn(II) to a basic extractant would be observed around 1.5–2.0 mol L –1 chloride for weak salting-out or salting-in agents, and the extraction of Zn(II) would not show a maximum for strong salting-out agents. This can indeed be observed in Figure 1 and clearly shows that a decrease in Zn(II)–chloride hydration caused by salting agent hydration becomes increasingly important when stronger salting-out agents are used.…”

Section: Resultsmentioning

confidence: 99%

Cation Effect of Chloride Salting Agents on Transition Metal Ion Hydration and Solvent Extraction by the Basic Extractant Methyltrioctylammonium Chloride

2020

View full text Add to dashboard Cite

The addition of a nonextractable salt has an important influence on the solvent extraction of metal ions, but the underlying principles are not completely understood yet. However, relating solute hydration mechanisms to solvent extraction equilibria is key to understanding the mechanism of solvent extraction of metal ions as a whole. We have studied the speciation of Co(II), Zn(II), and Cu(II) in aqueous solutions containing different chloride salts to understand their extraction to the basic extractant methyltrioctylammonium chloride (TOMAC). This includes the first speciation profile of Zn(II) in chloride media with the three Zn(II) species [Zn(H 2 O) 6 ] 2+ , [ZnCl 3 H 2 O] − , and [ZnCl 4 ] 2– . The observed differences in extraction efficiency for a given transition metal ion can be explained by transition metal ion hydration due to ion–solvent interactions, rather than by ion–solute interactions or by differences in speciation. Chloride salting agents bearing a cation with a larger hydration Gibbs free energy reduce the free water content more, resulting in a lower hydration for the transition metal ion. This destabilizes the transition metal chloro complex in the aqueous phase and increases the extraction efficiency. Salting agents with di- and trivalent cations reduce the transition metal chloro complex hydration less than expected, resulting in a lower extraction efficiency. The cations of these salting agents have a very large hydration Gibbs free energy, but the overall hydration of these salts is reduced due to significant salt ion pair formation. The general order of salting-out strength for the extraction of metal ions from chloride salt solutions is Cs + < Rb + < NH 4 + ≈ K + < Al 3+ ≈ Mg 2+ ≈ Ca 2+ ≈ Na + < Li + . These findings can help in predicting the optimal conditions for metal separation by solvent extraction and also contribute to a broader understanding of the effects of dissolved salts on solutes.

show abstract

“…The speciation of copper and gold in aqueous chloride solutions has been extensively researched in past decades, [40][41][42] and it was found that the prevailing copper chlorocomplexes in 4.5 , whereas gold is mostly present as AuCl 2…”

Section: Speciation Of Gold and Copper In Chloride Solutionsmentioning

confidence: 99%

Mechanism of selective gold extraction from multi-metal chloride solutions by electrodeposition-redox replacement

et al. 2020

View full text Add to dashboard Cite

show abstract

Determination of the Distribution of Cupric Chloro-Complexes in Hydrochloric Acid Solutions at 298 K

Cited by 13 publications

References 40 publications

Model for Metal Extraction from Chloride Media with Basic Extractants: A Coordination Chemistry Approach

Model for Metal Extraction from Chloride Media with Basic Extractants: A Coordination Chemistry Approach

Cation Effect of Chloride Salting Agents on Transition Metal Ion Hydration and Solvent Extraction by the Basic Extractant Methyltrioctylammonium Chloride

Mechanism of selective gold extraction from multi-metal chloride solutions by electrodeposition-redox replacement

Contact Info

Product

Resources

About