Importance of weak interactions in the formulation of organic phases for efficient liquid/liquid extraction of metals

Bourgeois, Damien; Maangar, Asmae El; Dourdain, Sandrine

doi:10.1016/j.cocis.2020.03.004

Cited by 43 publications

(33 citation statements)

References 83 publications

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“…The square planar geometry of d8 Pd II has been characterized previously on closely related malonamide systems, with one bidentate malonamide chelating the central Pd II cation . Thus, the extracted complexes are not likely to be supramolecular . Our experimental results are in full agreement with these data, which suggest a higher stability of the Pd‐sulfoxide complex in comparison with the Pd‐malonamide complex, which relative stability was quite surprising .…”

Section: Resultssupporting

confidence: 88%

From Electronic Waste to Suzuki−Miyaura Cross‐Coupling Reaction in Water: Direct Valuation of Recycled Palladium in Catalysis

et al. 2020

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From electronic waste to Pd-catalyzed reaction! The straightforward valuation of palladium recovered from electronic waste is reported here. Following a classical leaching stage, palladium is selectively extracted from a complex aqueous mixture of metallic cations into an organic phase. Afterwards, the judicious choice of a surfactant enables stabilization of palladium during back extraction cycles, and the direct preparation of an aqueous micellar solution, which can be employed in a model SuzukiÀ Miyaura cross-coupling reaction. Clean phase separation is observed, and distribution of all components between organic and aqueous phases is mastered. The proposed process avoids several waste generating steps dedicated to palladium isolation and ultimate purification, as well as the preparation of palladium pre-catalyst. This novel approach enables a better use of both natural resources and industrial wastes, through new cycles in circular economy.

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Section: Resultssupporting

confidence: 88%

From Electronic Waste to Suzuki−Miyaura Cross‐Coupling Reaction in Water: Direct Valuation of Recycled Palladium in Catalysis

et al. 2020

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“…Exact mechanism of metal ion extraction is yet unclear, but assistance of complexation-induced micelle formation in the aqueous phase [ 37 ] and organic phase [ 38 , 39 ] to the metal ion transfer through the water–oil interface was claimed and recently reviewed [ 40 ]. A number of methods was employed to ensure the absence of calixcrown aggregates in organic solvent before establishing the role of aggregation in cation extraction.…”

Section: Resultsmentioning

confidence: 99%

Switching Ion Binding Selectivity of Thiacalix[4]arene Monocrowns at Liquid–Liquid and 2D-Confined Interfaces

Muravev

Yakupov

Gerasimova

et al. 2021

IJMS

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Understanding the interaction of ions with organic receptors in confined space is of fundamental importance and could advance nanoelectronics and sensor design. In this work, metal ion complexation of conformationally varied thiacalix[4]monocrowns bearing lower-rim hydroxy (type I), dodecyloxy (type II), or methoxy (type III) fragments was evaluated. At the liquid–liquid interface, alkylated thiacalixcrowns-5(6) selectively extract alkali metal ions according to the induced-fit concept, whereas crown-4 receptors were ineffective due to distortion of the crown-ether cavity, as predicted by quantum-chemical calculations. In type-I ligands, alkali-metal ion extraction by the solvent-accessible crown-ether cavity was prevented, which resulted in competitive Ag+ extraction by sulfide bridges. Surprisingly, amphiphilic type-I/II conjugates moderately extracted other metal ions, which was attributed to calixarene aggregation in salt aqueous phase and supported by dynamic light scattering measurements. Cation–monolayer interactions at the air–water interface were monitored by surface pressure/potential measurements and UV/visible reflection–absorption spectroscopy. Topology-varied selectivity was evidenced, towards Sr2+ (crown-4), K+ (crown-5), and Ag+ (crown-6) in type-I receptors and Na+ (crown-4), Ca2+ (crown-5), and Cs+ (crown-6) in type-II receptors. Nuclear magnetic resonance and electronic absorption spectroscopy revealed exocyclic coordination in type-I ligands and cation–π interactions in type-II ligands.

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“…Long-range colloidal interactions have been suggested to play a role in determining selectivity of LLE in addition to the complexation between the extractant and the ion. 34,81 Our results show that the converse need not always be true -even when the complexation is the same for two ions, a difference in organic phase structure at the mesoscale does not imply higher selectivity in LLE. A similar phenomenon is observed with lanthanide bearing TOMA-NO 3 complex fluids wherein the organic phase structure is not correlated with metal concentration.…”

mentioning

confidence: 83%

Origins of Clustering of Metalate–Extractant Complexes in Liquid–Liquid Extraction

Nayak

Kumal

Liu

et al. 2021

ACS Appl. Mater. Interfaces

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Effective and energy efficient separation of precious and rare metals is very important for a variety of advanced technologies. Liquid-liquid extraction (LLE) is a relatively less energy intensive separation technique, widely used in separation of lanthanides, actinides, and platinum group metals (PGMs). In LLE, the distribution of an ion between an aqueous phase and an organic phase is determined by enthalpic (coordination interactions) and entropic (fluid reorganization) contributions. The molecular scale details of these contributions are not well understood. Preferential extraction of an ion from the aqueous phase is usually correlated with the resulting fluid organization in the organic phase, as the longer-range organization increases with metal loading. However, it is difficult to determine the extent to which organic phase fluid organization causes, or is caused by, metal loading. In this study, we demonstrate that two systems with the same metal loading may impart very different organic phase organization; and investigate the underlying molecular scale mechanism. Small angle X-ray scattering shows that the structure of a quaternary ammonium extractant solution in toluene is affected differently by the extraction of two metalates (octahedral PtCl 6 2and square-planar PdCl 4 2-), although both are completely transferred into the organic phase. The aggregates formed by the metalate-extractant complexes (approximated as reverse micelles) exhibit more long-range order (clustering) with PtCl 6 2compared to that with PdCl 4 2-. Vibrational sum frequency generation spectroscopy, and complimentary atomistic molecular dynamics simulations on model Langmuir monolayers, indicate that the two metalates affect the interfacial hydration structures differently. Further, the interfacial hydration is correlated with water extraction into the organic phase. These results support a strong relationship between the organic phase organizational structure and different local hydration present within the aggregates of metalate-extractant complexes, which is independent of metalate concentration. File list (2) download file view on ChemRxiv Origins_of_clustering_acsami_revised.pdf (1.94 MiB) download file view on ChemRxiv SI_Origins of clustering_acsami_revised.pdf (1.82 MiB)

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Importance of weak interactions in the formulation of organic phases for efficient liquid/liquid extraction of metals

Cited by 43 publications

References 83 publications

From Electronic Waste to Suzuki−Miyaura Cross‐Coupling Reaction in Water: Direct Valuation of Recycled Palladium in Catalysis

From Electronic Waste to Suzuki−Miyaura Cross‐Coupling Reaction in Water: Direct Valuation of Recycled Palladium in Catalysis

Switching Ion Binding Selectivity of Thiacalix[4]arene Monocrowns at Liquid–Liquid and 2D-Confined Interfaces

Origins of Clustering of Metalate–Extractant Complexes in Liquid–Liquid Extraction

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