236 research outputs found
Sujet de thèse en cours : Exploration numérique d'une contrainte mécanique sur les performances d'absorption de gaz dans des matériaux poreux de type MOF
No full textsupervisor Aziz Ghoufi (department of materials - nanosciences)sous la direction de Aziz Ghoufi dans le département Matériaux-Nanoscience
Relation entre propriétés structurales et interfaciales et de transport de liquides à liaison hydrogène dans le confinement nanométrique [Soutenance 13.12.2019]
No full textsupervisor Aziz Ghoufi (department of materials - nanosciences)sous la direction de Aziz Ghoufi dans le département Matériaux-Nanoscience
Computational exploration of the performances of mechanically constrained MOFs for hydrocarbon separation [Soutenance 18.02.2022]
No full textsupervisor Aziz Ghoufi (department of materials - nanosciences) and Guillaume Maurin (Montpellier)sous la direction de Aziz Ghoufi dans le département Matériaux-Nanosciences et Guillaume Maurin (Montpellier
Etude des mécanismes de transport de solvants organiques à travers des membranes de nanofiltration [Soutenance 19.12.2022]
No full textsupervisors Aziz Ghoufi (department of materials - nanosciences) and Anthony Szymczyk (ISCR)sous la direction d'Aziz Ghoufi (dans le département Matériaux-Nanosciences de l'IPR ) et Anthony Szymczyk (ISCR
Sujet de thèse en cours : Etude des processus de dessalement à travers des membranes de nitrure de bore et graphene nanoporeux par simulation moléculaire
No full textsupervisors Aziz Ghoufi (department of materials - nanosciences) and Ezzedine Ferjani (INRST)sous la Direction d'Aziz Ghoufi (dans le département Matériaux-Nanosciences de l'IPR ) et Ezzedine Ferjani (INRST
Adsorption of n-alkane vapours at the water surface
No full textInternational audienceMonte Carlo simulations are reported here to predict the surface tension of the liquid-vapour interface of water upon adsorption of alkane vapours (methane to hexane). A decrease of the surface tension has been established from n-pentane. A correlation has been evidenced between the decrease of the surface tension and the absence of specific arrangement at the water surface for n-pentane and n-hexane. The thermodynamic stability of the adsorption layer and the absence of film for longer alkanes have been checked through the calculation of a potential of mean force. This complements the work recently published [Ghoufi et al., Phys. Chem. Chem. Phys., 2010, 12, 5203] concerning the adsorption of methane at the water surface. The decrease of the surface tension has been interpreted in terms of the degree of hydrogen bonding of water molecules at the liquid-vapour interface upon adsorption
Confinement of Ter-Butanol Nanoclusters in Hydrophilic and Hydrophobic Silica Nanopores
No full textInternational audienceFrom hydrogen bonds, tert-butanol molecules self-organize in micelle-like supermolecular clusters in the liquid state. While these nanoclusters have been largely investigated in the bulk phase, the confined situation remains seldom. However, from a relevant combination of neutron scattering and molecular simulation, it has been shown that these clusters persisted under hydrophilic cylindrical confinement [Ghoufi, A.; Hureau, I.; Lefort, R.; Morineau, D. J. Phys. Chem. C, 2011, 115, 17761]. In this work, we provide a structural, dynamic, and dielectric characterization of nanoconfined tert-butanol in both hydrophilic and hydrophobic silica nanopores. Differences between hydrophilic and hydrophobic pores with respect to the bulk phase are correlated to the modulation in the hydrogen-bonding network induced by the nanometric confinement and the chemical nature of the solid surface
Surface free energy calculation of the solid–fluid interfaces from molecular simulation
No full textInternational audienceIn this work, I present a straightforward approach for computing surface free energy γF based on the assessment of surface internal energy (γU), avoiding the difficulty connected to the determination of the elastic contribution in the case of a solid surface. This methodology has thus been extended to the calculation of γF for the interface between the liquid–vapor phase of water, the solid–vapor interface of aluminum, the aluminum–water interface, rigid graphene–water solid–liquid interfaces, and the n-dodecane–water liquid–liquid interface
Importance of the tail corrections on surface tension of curved liquid-vapor interfaces
No full textInternational audienceWe report molecular simulations of the liquid-vapor cylindrical interface of methane. We apply the truncated Lennard-Jones potential and specific long-range corrections for the surface tension developed especially for cylindrical interfaces. We investigate the impact of the cutoff on the radial density profile, the intrinsic and long-range correction parts to the surface tension, and Tolman length. We also study the curvature dependence of the surface tension as a function of the cutoff used. In this work we shed light that both density and Tolman length are cutoff-dependent whereas the total surface tension is slightly curvature and cutoff dependent. © 2017 Author(s)
Molecular Modelling of electrolytes transport across nanoporous membranes
No full textLes procédés de séparation membranaires sont des techniques particulièrement adaptées aux exigences écologiques et industrielles en matière de traitement de l'eau. Parmi les différentes techniques de séparation existantes, la nanofiltration est un procédé économique permettant le dessalement et l'adoucissement de l'eau. En dépit du nombre croissant de travaux académiques ou industriels portant sur la nanofiltration ces dernières années, les phénomènes physiques impliqués dans le transport de solutés (en particuliers les sels) à travers les matériaux nanoporeux restent mal compris. En effet, les matériaux sont des membranes de polymère dont la structure est complexe et méconnue. Les propriétés des liquides en milieu confiné présentent de plus des propriétés inattendues. L'utilisation d'outils numériques permet d'explorer et d'améliorer la compréhension des mécanismes de transport à travers des membranes. Parmi les différentes approches existantes, les simulations de type dynamique moléculaire permettent de sonder les propriétés des liquides confinées à l'échelle moléculaire. L'objectif de cette thèse est d'analyser les propriétés de solutions aqueuses d'électrolytes confinées dans un nanopore modèle par simulation de dynamique moléculaire. Les systèmes étudiés sont constitués d'un pore de silice connecté à deux réservoirs contenant de l'eau salée. Deux types de simulations ont été réalisés. Au cours d'une simulation dite « à l'équilibre », les propriétés structurales, diélectriques et dynamiques des liquides ont été étudiées. Au cours des simulations ''hors-équilibre'', une différence de pression est appliquée entre les réservoirs afin de générer un écoulement. Les propriétés de transport de l'eau et des sels à travers le nanopore ont été étudiées. Ce travail s'inscrit dans le cadre du projet MUTINA financé par l'Agence Nationale de la Recherche (ANR 2011 BS09 002) portant sur la modélisation multi-échelle du transport d'ions en nanofiltration.Membrane processes are very powerful techniques in term of water treatment. Nanofiltration is a recent membrane process mainly used for water desalination and water softening. Although nanofiltration has attracted increasing attention over the recent years, physical phenomenon related to species (especially aqueous salts) inside the membranes are still poorly understood at the nanoscale. The membranes used in a nanofiltration process (polymeric membranes) are indeed very complex and little is known about their structure. Moreover, liquids in a confined phase exhibit very different behaviour with respect from a bulk phase. In order to investigate the transport mechanisms, modelling tools are often used to reproduce the liquids and membranes behaviour. Molecular dynamic simulations are very useful in that case to gain insight into the liquid properties at the molecular scale. The aim of this thesis is to improve the understanding of the electrolytes transport inside a model nanopore. For this purpose, molecular simulations were carried out to simulate two kind of systems composed of pore connected to reservoirs filled of water and salts. On one hand, we performed equilibrium simulations to analyse the structural, dielectric and dynamic properties of confined liquids. On the other hand, non-equilibrium simulations were performed to generate a pressure-driven fluid flow to investigate water and ions transport. This work is part of the MUTINA project founded by the French National Research Agency for Research (ANR 2011 BS09 002) about multi-scale modelling of ion transport in nanofiltration
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