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Bonnett BL, Rahman T, Poe D, Seifert S, Stephenson GB, Servis MJ. Insights into water extraction and aggregation mechanisms of malonamide-alkane mixtures. Phys Chem Chem Phys 2024; 26:18089-18101. [PMID: 38895844 DOI: 10.1039/d4cp01369g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Structure at the nanoscale in the organic phase of liquid-liquid extraction systems is often tied to separation performance. However, the weak interactions that drive extractant assembly lead to poorly defined structures that are challenging to identify. Here, we investigate the mechanism of water extraction for a malonamide extractant commonly applied to f-element separations. We measure extractant concentration fluctuations in the organic phase with small angle X-ray scattering (SAXS) before and after contact with water at fine increments of extractant concentration, finding no qualitative changes upon water uptake that might suggest significant nanoscopic reorganization of the solution. The critical composition for maximum fluctuation intensity is consistent with small water-extractant adducts. The extractant concentration dependence of water extraction is consistent with a power law close to unity in the low concentration regime, suggesting the formation of 1 : 1 water-extractant adducts as the primary extraction mechanism at low concentration. At higher extractant concentrations, the power law slope increases slightly, which we find is consistent with activity effects modeled using Flory-Huggins theory without introduction of additional extractant-water species. Molecular dynamics simulations are consistent with these findings. The decrease in interfacial tension with increasing extractant concentration shows a narrow plateau region, but it is not correlated with any change in fluctuation or water extraction trends, further suggesting no supramolecular organization such as reverse micellization. This study suggests that water extraction in this system is particularly simple: it relies on a single mechanism at all extractant concentrations, and only slightly enhances the concentration fluctuations characteristic of the dry binary extractant/diluent mixture.
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Affiliation(s)
- Brittany L Bonnett
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL 60439, USA.
| | - Tasnim Rahman
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL 60439, USA.
| | - Derrick Poe
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL 60439, USA.
| | - Soenke Seifert
- X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - G Brian Stephenson
- Materials Science Division, Argonne National Laboratory, Lemont, IL 60439, USA.
| | - Michael J Servis
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL 60439, USA.
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Massey D, Masters A, Macdonald-Taylor J, Woodhead D, Taylor R. Molecular Dynamics Study of the Aggregation Behavior of N, N, N', N'-Tetraoctyl Diglycolamide. J Phys Chem B 2022; 126:6290-6300. [PMID: 35975814 PMCID: PMC9421649 DOI: 10.1021/acs.jpcb.2c02198] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
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Liquid–liquid extraction is a commonly used technique
to
separate metals and is a process that has particular relevance to
the nuclear industry. There has been a drive to use environmentally
friendly ligands composed only of carbon, hydrogen, nitrogen, and
oxygen. One example is the i-SANEX process that has been developed
to separate minor actinides from spent nuclear fuel. The underlying
science of such processes, is, however, both complex and intriguing.
Recent research indicates that the liquid phases involved are frequently
structured fluids with a hierarchical organization of aggregates.
Effective flow-sheet modeling of such processes is likely to benefit
from the knowledge of the fundamental properties of these phases.
As a stepping stone toward this, we have performed molecular dynamics
simulations on a metal free i-SANEX system composed of the ligand N,N,N′,N′-tetraoctyl diglycolamide (TODGA), diluent hydrogenated
tetrapropylene (TPH), and polar species water and nitric acid. We
have also studied the effects of adding n-octanol
and swapping TPH for n-dodecane. It would seem sensible
to understand this simpler system before introducing metal complexes.
Such an understanding would ideally arise from studying the system’s
properties over a wide range of compositions. The large number of
components, however, precludes a comprehensive scan of compositions,
so we have chosen to study a fixed concentration of TODGA while varying
the concentrations of water and nitric acid over a substantial range.
Reverse aggregates are observed, with polar species in the interior
in contact with the polar portions of the TODGA molecules and the
organic diluent on the exterior in contact with the TODGA alkyl chains.
These aggregates are irregular in shape and grow in size as the amount
of water and nitric acid increases. At a sufficiently high polar content,
a single extended cluster forms corresponding to the third phase formation.
No well-defined bonding motifs were observed between the polar species
and TODGA. The cluster size distribution fits an isodesmic model,
where the Gibbs energy change of adding a TODGA molecule to a cluster
ranges between 4.5 and 7.0 kJ mol–1, depending on
the system composition. The addition of n-octanol
was found to reduce the degree of aggregation, with n-octanol acting as a co-surfactant. Exchanging the diluent TPH for n-dodecane also decreased the aggregation. We present evidence
that this is due to the greater penetration of n-dodecane
into the reverse aggregates. It is known, however, that the propensity
for the third phase formation is greater with n-dodecane
as the diluent than is the case with TPH, but we argue that these
two results are not contradictory. This research casts light on the
driving forces for aggregation, informs process engineers as to what
species are present, and indicates that flow-sheet liquid–liquid
extraction modeling might benefit by incorporating an isodesmic aggregation
approach.
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Affiliation(s)
- Daniel Massey
- Department of Chemical Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Andrew Masters
- Department of Chemical Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Jonathan Macdonald-Taylor
- National Nuclear Laboratory, 5th Floor Chadwick House, Warrington Road, Birchwood Park, Warrington WA3 6AE, U.K
| | - David Woodhead
- National Nuclear Laboratory, Central Laboratory, Sellafield, Seascale CA20 1PG, U.K
| | - Robin Taylor
- National Nuclear Laboratory, Central Laboratory, Sellafield, Seascale CA20 1PG, U.K
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Sheyfer D, Servis MJ, Zhang Q, Lal J, Loeffler T, Dufresne EM, Sandy AR, Narayanan S, Sankaranarayanan SKRS, Szczygiel R, Maj P, Soderholm L, Antonio MR, Stephenson GB. Advancing Chemical Separations: Unraveling the Structure and Dynamics of Phase Splitting in Liquid-Liquid Extraction. J Phys Chem B 2022; 126:2420-2429. [PMID: 35315675 DOI: 10.1021/acs.jpcb.1c09996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Liquid-liquid extraction (LLE), the go-to process for a variety of chemical separations, is limited by spontaneous organic phase splitting upon sufficient solute loading, called third phase formation. In this study we explore the applicability of critical phenomena theory to gain insight into this deleterious phase behavior with the goal of improving separations efficiency and minimizing waste. A series of samples representative of rare earth purification were constructed to include each of one light and one heavy lanthanide (cerium and lutetium) paired with one of two common malonamide extractants (DMDOHEMA and DMDBTDMA). The resulting postextraction organic phases are chemically complex and often form rich hierarchical structures whose statics and dynamics near the critical point were probed herein with small-angle X-ray scattering and high-speed X-ray photon correlation spectroscopy. Despite their different extraction behaviors, all samples show remarkably similar critical behavior with exponents well described by classical critical point theory consistent with the 3D Ising model, where the critical behavior is characterized by fluctuations with a single diverging length scale. This unexpected result indicates a significant reduction in relevant chemical parameters at the critical point, indicating that the underlying behavior of phase transitions in LLE rely on far fewer variables than are generally assumed. The obtained scalar order parameter is attributed to the extractant fraction of the extractant/diluent mixture, revealing that other solution components and their respective concentrations simply shift the critical temperature but do not affect the nature of the critical fluctuations. These findings point to an opportunity to drastically simplify studies of liquid-liquid phase separation and phase diagram development in general while providing insights into LLE process improvement.
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Affiliation(s)
- D Sheyfer
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Michael J Servis
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Qingteng Zhang
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - J Lal
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
- Department of Physics, Northern Illinois University, DeKalb, Illinois 60115, United States
| | - T Loeffler
- Nanoscale Science and Technology Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - E M Dufresne
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - A R Sandy
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - S Narayanan
- X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Subramanian K R S Sankaranarayanan
- Nanoscale Science and Technology Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
- Department of Mechanical and Industrial Engineering, University of Illinois, Chicago, Illinois 60607,United States
| | - R Szczygiel
- AGH University of Science and Technology, Krakow 30-059, Poland
| | - P Maj
- AGH University of Science and Technology, Krakow 30-059, Poland
| | - L Soderholm
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Mark R Antonio
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - G B Stephenson
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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Sittel T, Weßling P, Großmann D, Engels E, Geist A, Panak PJ. Spectroscopic Investigation of the covalence in An(III) complexes with Tetraethylcarboxamidopyridine. Dalton Trans 2022; 51:8028-8035. [DOI: 10.1039/d2dt00757f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, we report a combined NMR spectroscopic and time-resolved laser fluorescence spectroscopic (TRLFS) study of the complexation of N,N,N',N'-tetraethyl-2,6-carboxamidopyridine (Et-Pic) with Ln(III) (La, Sm, Eu, Lu), Y(III) and...
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Liu J, Chen B, Liu Y, Ma J, Li X, Yang Y. Selective extraction of Am(III) from Cm(III) and Eu(III) using a novel phenanthrolinamide ligand: Thermodynamics, species, and structure. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.119119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Servis MJ, Piechowicz M, Soderholm L. Impact of Water Extraction on Malonamide Aggregation: A Molecular Dynamics and Graph Theoretic Approach. J Phys Chem B 2021; 125:6629-6638. [PMID: 34128673 DOI: 10.1021/acs.jpcb.1c02962] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Solution structure in liquid-liquid extraction affects the efficacy of separation; however, even for simplified organic phases, structural characterization and attribution of aggregation to intermolecular interactions are fundamental challenges. We investigate water uptake into organic phases for two malonamides commonly applied to actinide and lanthanide separations. Extracted water induces reorganization of the amphiphilic extractant molecules, although we find this rearrangement is not strongly manifested in small-angle X-ray scattering making it challenging to probe without methods such as atomistic simulation. Using a graph theoretic approach to define hydrogen bonded water/malonamide aggregates from molecular dynamics simulations, we find evidence of a characteristic aggregate size by water number that results from geometric accommodation of the surrounding malonamide molecules. This implies a degree of size selectivity inherent to these water-in-oil aggregates. Conversely, we find no evidence of a characteristic size of the aggregates with respect to their malonamide number. By defining a separate graphical representation of self-association of the amphiphilic malonamides, we quantify how water affects the local and nonlocal topology of the malonamide network, providing a basis for characterization of the structure and impact of polar solutes in increasingly complex organic phases.
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Affiliation(s)
- Michael J Servis
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Marek Piechowicz
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - L Soderholm
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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Geist A, Adnet JM, Bourg S, Ekberg C, Galán H, Guilbaud P, Miguirditchian M, Modolo G, Rhodes C, Taylor R. An overview of solvent extraction processes developed in Europe for advanced nuclear fuel recycling, part 1 — heterogeneous recycling. SEP SCI TECHNOL 2020. [DOI: 10.1080/01496395.2020.1795680] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Andreas Geist
- Karlsruhe Institute of Technology (KIT), Institute for Nuclear Waste Disposal (INE), Karlsruhe, Germany
| | - Jean-Marc Adnet
- French Alternative Energies and Atomic Energy Commission, CEA/DES/ISEC/DMRC, University of Montpellier, Marcoule, France
| | - Stéphane Bourg
- French Alternative Energies and Atomic Energy Commission, CEA/DES/ISEC/DMRC, University of Montpellier, Marcoule, France
| | - Christian Ekberg
- Nuclear Chemistry, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Hitos Galán
- Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
| | - Philippe Guilbaud
- French Alternative Energies and Atomic Energy Commission, CEA/DES/ISEC/DMRC, University of Montpellier, Marcoule, France
| | - Manuel Miguirditchian
- French Alternative Energies and Atomic Energy Commission, CEA/DES/ISEC/DMRC, University of Montpellier, Marcoule, France
| | - Giuseppe Modolo
- Forschungszentrum Jülich GmbH (FZJ), Institut für Energie- und Klimaforschung, Nukleare Entsorgung und Reaktorsicherheit (IEK-6), Jülich, Germany
| | - Chris Rhodes
- National Nuclear Laboratory, Central Laboratory, Seascale, UK
| | - Robin Taylor
- National Nuclear Laboratory, Central Laboratory, Seascale, UK
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