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Dufrêche JF, Siboulet B, Duvail M. Chemical models for dense solutions. Faraday Discuss 2024. [PMID: 39041303 DOI: 10.1039/d4fd00084f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Here we examine the question of the chemical models widely used to describe dense solutions, particularly ionic solutions. First, a simple macroscopic analysis shows that, in the case of weak interactions, taking into account aggregated species amounts to modelling an effective attraction between solutes, although the stoichiometry used does not necessarily correspond to atomic reality. We then use a rigorous microscopic analysis to explain how, in the very general case, chemical models can be obtained from an atomic physical description. We show that there are no good or bad chemical models as long as we consider exact calculations. To obtain the simplest possible description, it is nevertheless advisable to take the speciation criterion that minimises the excess terms. Molecular simulations show that, very often, species can be defined simply by grouping ions which are in direct contact. In some cases, the appearance of macroscale clusters can be predicted.
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Affiliation(s)
- J-F Dufrêche
- ICSM, University of Montpellier, CEA, CNRS, ENSCM, Marcoule, France.
| | - B Siboulet
- ICSM, University of Montpellier, CEA, CNRS, ENSCM, Marcoule, France.
| | - M Duvail
- ICSM, University of Montpellier, CEA, CNRS, ENSCM, Marcoule, France.
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2
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Bi S, Salanne M. Cluster analysis as a tool for quantifying structure-transport properties in simulations of superconcentrated electrolyte. Chem Sci 2024; 15:10908-10917. [PMID: 39027304 PMCID: PMC11253178 DOI: 10.1039/d4sc01491j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 06/09/2024] [Indexed: 07/20/2024] Open
Abstract
Using molecular dynamics simulations and graph-theory-based cluster analysis, we investigate the structure-transport properties of typical water-in-salt electrolytes. We demonstrate that ions exhibit distinct dynamics across different ionic clusters-namely, solvent-separated ion pairs (SSIPs), contact ion pairs (CIPs), and aggregates (AGGs). We assess the average proportions of various ionic species and their lifetimes. Our method reveals a dynamic decoupling of ion kinetics, with each species independently contributing to the overall molecular motion. This is evidenced by the fact that the total velocity autocorrelation function (VACF) and power spectrum can be expressed as a weighted sum of independent functions for each species. The experimental data on the ionic conductivity of the studied LiTFSI electrolytes align well with our theoretical predictions at various concentrations, based on the proportions and diffusion coefficients of free ions derived from our analysis. The insights gained into the solvation structures and dynamics of different ionic species enable us to elucidate the physical mechanisms driving ion transport in such superconcentrated electrolytes, providing a comprehensive framework for the future design and optimization of electrolytes.
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Affiliation(s)
- Sheng Bi
- Sorbonne Université, CNRS, Physicochimie des Électrolytes et Nanosystèmes Interfaciaux F-75005 Paris France
- Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459 80039 Amiens Cedex France
| | - Mathieu Salanne
- Sorbonne Université, CNRS, Physicochimie des Électrolytes et Nanosystèmes Interfaciaux F-75005 Paris France
- Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459 80039 Amiens Cedex France
- Institut Universitaire de France (IUF) 75231 Paris France
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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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Verma PK, Karak A, Sahu P, Aswal VK, Mahanty B, Ali SM, Egberink RJM, Huskens J, Verboom W, Mohapatra PK. Aggregation Behavior of Nitrilotriacetamide (NTAmide) Ligands in Thorium(IV) Extraction from Acidic Medium: Small-Angle Neutron Scattering, Fourier Transform Infrared, and Theoretical Studies. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:14745-14759. [PMID: 36394314 DOI: 10.1021/acs.langmuir.2c02394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Two tripodal amides obtained from nitrilotriacetic acid with n-butyl and n-octyl alkyl chains (HBNTA(LI) and HONTA(LII), respectively) were studied for the extraction of Th(IV) ions from nitric acid medium. The effect of the diluent medium, i.e., n-dodecane alone and a mixture of n-dodecane and 1-decanol, onto aggregate formation were investigated using small angle neutron scattering (SANS) studies. In addition, the influence of the ligand structure, nitric acid, and Th(IV) loading onto ligand aggregation and third-phase formation tendency was discussed.The LI/LII exist as monomers (aggregarte radius for LI: 6.0 Å; LII:7.4 Å) in the presence of 1-decanol, whereas LII forms dimers (aggregarte radius for LII:9.3 Å; LI does not dissolve in n-dodecane) in the absence of 1-decanol. The aggregation number increases for both the ligands after HNO3 and Th(IV) loading. The maximum organic concentration (0.050 ± 0.004 M) of Th(IV) was reached without third-phase formation for 0.1 M LI/LII dissolved in 20% isodecanol +80% n-dodecane. The interaction of 1-decanol with LII and HNO3/Th(IV) with amidic oxygens of LI/LII results in shift of carbonyl stretching frequency, as shown by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) studies. The structural and bonding information of the Th-LI/LII complex were derived from the density functional theoretical (DFT) studies. The molecular dynamics (MD) simulations suggested that the aggregation behavior of the ligand in the present system is governed by the population of hydrogen bonds by phase modifier around the ligand molecules. Although the theoretical studies suggested higher Gibbs free energy of complexation for Th4+ ions with LI than LII, the extraction was found to be higher with the latter, possibly due to the higher lipophilicity and solubility of the Th-LII aggregate in the nonpolar media.
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Affiliation(s)
- Parveen K Verma
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai400094, India
| | - Ananda Karak
- Homi Bhabha National Institute, Anushaktinagar, Mumbai400094, India
- INRPO, FF, Nuclear Recycle Board, Bhabha Atomic Research Centre, Tarapur, Mumbai400085, India
| | - Pooja Sahu
- Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai91400085, India
| | - Vinod K Aswal
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai400085, India
| | - Bholanath Mahanty
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai400094, India
| | - Sk Musharaf Ali
- Homi Bhabha National Institute, Anushaktinagar, Mumbai400094, India
- Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai91400085, India
| | - Richard J M Egberink
- Laboratory of Molecular Nanofabrication, Department for Molecules & Materials, MESA+ Institute, University of Twente, P.O. Box 217, 7500 AEEnschede, The Netherlands
| | - Jurriaan Huskens
- Laboratory of Molecular Nanofabrication, Department for Molecules & Materials, MESA+ Institute, University of Twente, P.O. Box 217, 7500 AEEnschede, The Netherlands
| | - Willem Verboom
- Laboratory of Molecular Nanofabrication, Department for Molecules & Materials, MESA+ Institute, University of Twente, P.O. Box 217, 7500 AEEnschede, The Netherlands
| | - Prasanta K Mohapatra
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai400094, India
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Le Crom S, Dourdain S, Pellet-Rostaing S, Duvail M. Long-Range Organization Study of Piperidinium-Based Ionic Liquids by Polarizable Molecular Dynamics Simulations. J Phys Chem B 2022; 126:3355-3365. [PMID: 35471118 DOI: 10.1021/acs.jpcb.2c01123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The nanoscale organization of some classes of ionic liquids is responsible for their singular properties. In this paper, we use polarizable molecular dynamics simulations and small-angle X-ray scattering to probe the structure of two piperidinium- and (trifluoromethylsulfonyl)imide-based ionic liquids ([EBPip+][NTf2-] and [EOPip+][NTf2-]) that differ in the alkyl chain length of their cation. The X-ray scattering intensities calculated numerically, from the radial distribution functions, are in excellent agreement with the experimental data. The analysis of the different contributions of the X-ray scattering data allowed us to highlight the correlations responsible for the low q peak observed for the long-chain alkyl cations. New angular analyses showed that anions were more likely to align with alkyl chains as their size increased, inducing angular correlation between anions at larger distances. They also showed that the long alkyl chains of the cations aligned more with each other than the short ones. These more aligned alkyl chains induce a smaller volume of the apolar microdomains compared to the well-studied imidazolium-based ionic liquids, leading to the smaller correlation distance for piperidinium-based ionic liquids.
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Affiliation(s)
| | | | | | - Magali Duvail
- ICSM, Univ Montpellier, CEA, CNRS, ENSCM, Bagnols-sur-Cèze, France
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Yang P, Jia S, Wang Y, Li Z, Wu S, Wang J, Gong J. Dissolution behavior, thermodynamic and kinetic analysis of malonamide by experimental measurement and molecular simulation. Chin J Chem Eng 2022. [DOI: 10.1016/j.cjche.2022.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Stemplinger S, Duvail M, Dufrêche JF. Molecular dynamics simulations of Eu(NO3)3 salt with DMDOHEMA in n-alkanes: Unravelling curvature properties in liquid-liquid extraction. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118035] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Habibzadeh Mashatooki M, Ghalami-Choobar B. Improved drug delivery and competitive adsorption of paclitaxel and mitomycin C anticancer drugs on the Boron-nitride nanoparticles: A molecular dynamics insight. Phys Chem Chem Phys 2022; 24:6639-6654. [DOI: 10.1039/d1cp04006e] [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
The competitive aggregated adsorption and molecular interactions between paclitaxel (PX) and mitomycin C (MMC) molecules on the surface of boron nitride nanosheet (BNNS) was investigated using molecular dynamics method. BNNS...
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Moreno Martinez D, Acher E, Vatin M, Dourdain S, Guillaumont D, Guilbaud P. Aggregation of Bifunctional Extractants Used for Uranium(VI) Separation. J Phys Chem B 2021; 125:10759-10771. [PMID: 34320806 DOI: 10.1021/acs.jpcb.1c03529] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
DEHCNPB (butyl-N,N-di(2-ethylhexyl)carbamoyl-nonylphosphonate) is an amido-phosphonic acid that has remarkable properties for the separation of uranium from wet phosphoric acid. Despite previous studies, a detailed description of the DEHCNPB organic solutions at the supramolecular and molecular scales is missing. In the present work, we use classical Molecular Dynamics (MD) combined with SANS and SAXS experimental data in order to describe the aggregation of the bifunctional extractant DEHCNPB as well as the speciation of uranium(VI) in such systems. We provide a fine description of the molecular species in the organic solution and of the interactions within the aggregates formed, shedding light on solvent extraction mechanisms. Without uranium, the organic phase is highly composed of dimers and trimers H-bonded through phosphonate functions and without water molecules. With uranium, two to three extractant molecules coordinate directly the uranyl cation by their phosphonate groups. Uranyl is not fully dehydrated in this organic solution, and the amide groups of the extractants are found to form H-bonds with the water molecules bound to uranyl. These H-bond networks around the metallic cation stabilize the complexes and facilitate the extraction. These results underline the importance of considering weak interactions in the understanding of extraction processes and demonstrate how molecular simulations provide essential insights into such complex organic phase chemistry with a high number of species.
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Affiliation(s)
| | - Eléonor Acher
- CEA, DES, ISEC, DMRC, Univ Montpellier, Bagnols sur Ceze 30207, France
| | - Marin Vatin
- ICSM, Univ Montpellier, CEA, CNRS, ENSCM, Marcoule, France
| | | | | | - Philippe Guilbaud
- CEA, DES, ISEC, DMRC, Univ Montpellier, Bagnols sur Ceze 30207, France
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Servis MJ, Stephenson GB. Mesostructuring in Liquid-Liquid Extraction Organic Phases Originating from Critical Points. J Phys Chem Lett 2021; 12:5807-5812. [PMID: 34137623 DOI: 10.1021/acs.jpclett.1c01429] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Organic phase structure plays an important role in solute extraction energetics and phase behavior of liquid-liquid extraction (LLE) systems. For a binary extractant (amphiphile)/solvent mixture of relevance to LLE, we find that the organic phase mesostructuring is consistent with extractant concentration fluctuations as the compositional isotherm traverses the Widom line above its liquid-liquid critical point. This reveals a different mechanism for the well-documented heterogeneities in LLE organic phases that are typically attributed to micellization.
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Affiliation(s)
- Michael J Servis
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - G B Stephenson
- Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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