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Sardo M, Morais T, Soares M, Vieira R, Ilkaeva M, Lourenço MAO, Marín-Montesinos I, Mafra L. Unravelling the structure of CO 2 in silica adsorbents: an NMR and computational perspective. Chem Commun (Camb) 2024; 60:4015-4035. [PMID: 38525497 PMCID: PMC11003455 DOI: 10.1039/d3cc05942a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 03/08/2024] [Indexed: 03/26/2024]
Abstract
This comprehensive review describes recent advancements in the use of solid-state NMR-assisted methods and computational modeling strategies to unravel gas adsorption mechanisms and CO2 speciation in porous CO2-adsorbent silica materials at the atomic scale. This work provides new perspectives for the innovative modifications of these materials rendering them more amenable to the use of advanced NMR methods.
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Affiliation(s)
- Mariana Sardo
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Tiago Morais
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
- Department of Chemistry, University of Iceland, Science Institute, Dunhaga 3, 107 Reykjavik, Iceland
| | - Márcio Soares
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Ricardo Vieira
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Marina Ilkaeva
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
- Department of Chemical and Environmental Engineering, University of Oviedo, Av. Julián Clavería 8, 33006 Oviedo, Spain
| | - Mirtha A O Lourenço
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Ildefonso Marín-Montesinos
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Luís Mafra
- CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
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2
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Aguilar-Huerta E, Cordero-Sánchez S, Rojas-González F, Villegas-Cortez J. Description of the thickness of the adsorbed layer, identification of the instability characteristics of the liquid–vapour interface and assessment of criticality in elliptical pores through the Broekhoff de Boer theory. ADSORPTION 2021. [DOI: 10.1007/s10450-021-00326-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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3
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Kraus H, Rybka J, Höltzel A, Trebel N, Tallarek U, Hansen N. PoreMS: a software tool for generating silica pore models with user-defined surface functionalisation and pore dimensions. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2020.1871478] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Hamzeh Kraus
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Stuttgart, Germany
| | - Julia Rybka
- Department of Chemistry, Philipps-Universität Marburg, Marburg, Germany
| | - Alexandra Höltzel
- Department of Chemistry, Philipps-Universität Marburg, Marburg, Germany
| | - Nicole Trebel
- Department of Chemistry, Philipps-Universität Marburg, Marburg, Germany
| | - Ulrich Tallarek
- Department of Chemistry, Philipps-Universität Marburg, Marburg, Germany
| | - Niels Hansen
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Stuttgart, Germany
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4
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Recent Advances in Computational Protocols Addressing Intrinsically Disordered Proteins. Biomolecules 2019; 9:biom9040146. [PMID: 30979035 PMCID: PMC6523529 DOI: 10.3390/biom9040146] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/09/2019] [Accepted: 04/10/2019] [Indexed: 01/09/2023] Open
Abstract
Intrinsically disordered proteins (IDP) are abundant in the human genome and have recently emerged as major therapeutic targets for various diseases. Unlike traditional proteins that adopt a definitive structure, IDPs in free solution are disordered and exist as an ensemble of conformations. This enables the IDPs to signal through multiple signaling pathways and serve as scaffolds for multi-protein complexes. The challenge in studying IDPs experimentally stems from their disordered nature. Nuclear magnetic resonance (NMR), circular dichroism, small angle X-ray scattering, and single molecule Förster resonance energy transfer (FRET) can give the local structural information and overall dimension of IDPs, but seldom provide a unified picture of the whole protein. To understand the conformational dynamics of IDPs and how their structural ensembles recognize multiple binding partners and small molecule inhibitors, knowledge-based and physics-based sampling techniques are utilized in-silico, guided by experimental structural data. However, efficient sampling of the IDP conformational ensemble requires traversing the numerous degrees of freedom in the IDP energy landscape, as well as force-fields that accurately model the protein and solvent interactions. In this review, we have provided an overview of the current state of computational methods for studying IDP structure and dynamics and discussed the major challenges faced in this field.
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Jorge M, Milne AW, Sobek ON, Centi A, Pérez-Sánchez G, Gomes JRB. Modelling the self-assembly of silica-based mesoporous materials. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1427237] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Miguel Jorge
- Department of Chemical and Process Engineering, University of Strathclyde, Glasgow, UK
| | - Andrew W. Milne
- Department of Chemical and Process Engineering, University of Strathclyde, Glasgow, UK
| | - Olivia N. Sobek
- Department of Chemical and Process Engineering, University of Strathclyde, Glasgow, UK
| | - Alessia Centi
- Department of Chemical and Process Engineering, University of Strathclyde, Glasgow, UK
- Max Planck Institute for Polymer Research, Mainz, Germany
| | - Germán Pérez-Sánchez
- CICECO – Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - José R. B. Gomes
- CICECO – Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
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Hiratsuka T, Tanaka H, Miyahara MT. Critical energy barrier for capillary condensation in mesopores: Hysteresis and reversibility. J Chem Phys 2017; 144:164705. [PMID: 27131561 DOI: 10.1063/1.4947243] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Capillary condensation in the regime of developing hysteresis occurs at a vapor pressure, Pcond, that is less than that of the vapor-like spinodal. This is because the energy barrier for the vapor-liquid transition from a metastable state at Pcond becomes equal to the energy fluctuation of the system; however, a detailed mechanism of the spontaneous transition has not been acquired even through extensive experimental and simulation studies. We therefore construct accurate atomistic silica mesopore models for MCM-41 and perform molecular simulations (gauge cell Monte Carlo and grand canonical Monte Carlo) for argon adsorption on the models at subcritical temperatures. A careful comparison between the simulation and experiment reveals that the energy barrier for the capillary condensation has a critical dimensionless value, Wc (*) = 0.175, which corresponds to the thermal fluctuation of the system and depends neither on the mesopore size nor on the temperature. We show that the critical energy barrier Wc (*) controls the capillary condensation pressure Pcond and also determines a boundary between the reversible condensation/evaporation regime and the developing hysteresis regime.
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Affiliation(s)
| | - Hideki Tanaka
- Department of Chemical Engineering, Kyoto University, Kyoto 615-8025, Japan
| | - Minoru T Miyahara
- Department of Chemical Engineering, Kyoto University, Kyoto 615-8025, Japan
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He X, Monk J, Singh R, Hung FR. Molecular modelling of ionic liquids in the ordered mesoporous carbon CMK-5. MOLECULAR SIMULATION 2015. [DOI: 10.1080/08927022.2015.1089992] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Coasne B. Effect of surface texture on freezing in nanopores: surface-induced versus homogeneous crystallization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2706-2713. [PMID: 25685867 DOI: 10.1021/la5041213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Freezing of argon in ordered and disordered carbon pores of a similar diameter D ∼ 2.4 nm is investigated using extensive molecular simulations with large system sizes up to 10(4) atoms. While crystallization in the atomistically smooth pore consists in a surface-induced phase transition occurring at a temperature larger than the bulk, crystallization in the disordered pores, which is only partial as it is spatially restricted to the pore center, occurs through homogeneous crystallization. These results shed light on solidification in pores by showing that there is a crossover between surface-induced and homogeneous crystallization upon increasing the surface disorder of the host material. In the latter case, the Gibbs-Thomson equation, in which crystallization is assumed to occur when the crystal size equals the pore size corrected for the thickness of the unfreezable layer at the pore surface, is in reasonable agreement with the observed freezing temperature.
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Affiliation(s)
- Benoit Coasne
- MultiScale Materials Science for Energy and Environment, UMI 3466 CNRS-MIT, and Department of Civil and Environmental Engineering, Massachusetts Institute of Technology , Cambridge Massachusetts 02139, United States
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Hartkamp R, Siboulet B, Dufrêche JF, Coasne B. Ion-specific adsorption and electroosmosis in charged amorphous porous silica. Phys Chem Chem Phys 2015; 17:24683-95. [DOI: 10.1039/c5cp03818a] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aqueous electrolyte solutions (NaCl, KCl, CsCl, and SrCl2) confined in a negatively charged amorphous silica slit pore.
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Affiliation(s)
- Remco Hartkamp
- Institut Charles Gerhardt Montpellier
- CNRS (UMR 5253)
- Université Montpellier 2
- ENSCM
- 34296 Montpellier Cedex 05
| | - Bertrand Siboulet
- Institute for Separation Chemistry of Marcoule (UMR 5257)
- CNRS/CEA/Université Montpellier – ENSCM Centre de Marcoule Bât. 426
- F-30207 Bagnols-sur-Cèze Cedex
- France
| | - Jean-François Dufrêche
- Institute for Separation Chemistry of Marcoule (UMR 5257)
- CNRS/CEA/Université Montpellier – ENSCM Centre de Marcoule Bât. 426
- F-30207 Bagnols-sur-Cèze Cedex
- France
| | - Benoit Coasne
- Institut Charles Gerhardt Montpellier
- CNRS (UMR 5253)
- Université Montpellier 2
- ENSCM
- 34296 Montpellier Cedex 05
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10
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Hantal G, Brochard L, Laubie H, Ebrahimi D, Pellenq RJM, Ulm FJ, Coasne B. Atomic-scale modelling of elastic and failure properties of clays. Mol Phys 2014. [DOI: 10.1080/00268976.2014.897393] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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11
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Tourné-Péteilh C, Coasne B, In M, Brevet D, Devoisselle JM, Vioux A, Viau L. Surfactant behavior of ionic liquids involving a drug: from molecular interactions to self-assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:1229-38. [PMID: 24437472 DOI: 10.1021/la404166y] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Aggregates formed in an aqueous medium by three ionic liquids CnMImIbu made up of 1-alkyl-3-methyl-imidazolium cation (n = 4, 6, 8) and ibuprofenate anion are investigated. Dynamic light scattering (DLS), cryogenic transmission electron microscopy (cryo-TEM), (1)H nuclear magnetic resonance measurements, and atom-scale molecular dynamics simulations are used to shed light on the main interactions governing the formation of the aggregates and their composition. At high concentration, mixed micelles are formed with a composition that depends on the imidazolium alkyl chain length. For the shortest alkyl chain, micelles are mainly composed of ibuprofenate anions with some imidazolium cations intercalated between the anions. Upon increasing the alkyl chain length, the composition of the aggregates gets enriched in imidazolium cations and aggregates of stoichiometric composition are obtained. Attractive interactions between these aggregates led to the formation of larger aggregates. As suggested by molecular simulations, these larger aggregates might constitute the early stage of phase separation. Transitions from micelles to vesicles or ribbons are observed due to dilution effects and changes in the chemical composition of the aggregates. We also show that aggregation can be probed using simple microscopic quantities such as radial distribution functions and average solvation numbers.
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Affiliation(s)
- Corine Tourné-Péteilh
- Institut Charles Gerhardt Montpellier, UMR 5253, CNRS-UM2-ENSCM-UM1 Place Eugène Bataillon, CC1701, 34095 Montpellier, France
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12
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Billemont P, Coasne B, De Weireld G. Adsorption of carbon dioxide-methane mixtures in porous carbons: effect of surface chemistry. ADSORPTION 2013. [DOI: 10.1007/s10450-013-9570-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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13
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Coasne B, Galarneau A, Gerardin C, Fajula F, Villemot F. Molecular simulation of adsorption and transport in hierarchical porous materials. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:7864-7875. [PMID: 23718554 DOI: 10.1021/la401228k] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Adsorption and transport in hierarchical porous solids with micro- (~1 nm) and mesoporosities (>2 nm) are investigated by molecular simulation. Two models of hierarchical solids are considered: microporous materials in which mesopores are carved out (model A) and mesoporous materials in which microporous nanoparticles are inserted (model B). Adsorption isotherms for model A can be described as a linear combination of the adsorption isotherms for pure mesoporous and microporous solids. In contrast, adsorption in model B departs from adsorption in pure microporous and mesoporous solids; the inserted microporous particles act as defects, which help nucleate the liquid phase within the mesopore and shift capillary condensation toward lower pressures. As far as transport under a pressure gradient is concerned, the flux in hierarchical materials consisting of microporous solids in which mesopores are carved out obeys the Navier-Stokes equation so that Darcy's law is verified within the mesopore. Moreover, the flow in such materials is larger than in a single mesopore, due to the transfer between micropores and mesopores. This nonzero velocity at the mesopore surface implies that transport in such hierarchical materials involves slippage at the mesopore surface, although the adsorbate has a strong affinity for the surface. In contrast to model A, flux in model B is smaller than in a single mesopore, as the nanoparticles act as constrictions that hinder transport. By a subtle effect arising from fast transport in the mesopores, the presence of mesopores increases the number of molecules in the microporosity in hierarchical materials and, hence, decreases the flow in the micropores (due to mass conservation). As a result, we do not observe faster diffusion in the micropores of hierarchical materials upon flow but slower diffusion, which increases the contact time between the adsorbate and the surface of the microporosity.
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Affiliation(s)
- Benoit Coasne
- Institut Charles Gerhardt Montpellier, CNRS (UMR 5253), Université Montpellier 2, ENSCM, Université Montpellier 1, 8 rue de l'Ecole Normale, 34296 Montpellier Cedex 05, France.
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Tanaka H, Hiratsuka T, Nishiyama N, Mori K, Miyahara MT. Capillary condensation in mesoporous silica with surface roughness. ADSORPTION 2013. [DOI: 10.1007/s10450-013-9486-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Coasne B, Galarneau A, Pellenq RJM, Di Renzo F. Adsorption, intrusion and freezing in porous silica: the view from the nanoscale. Chem Soc Rev 2013; 42:4141-71. [PMID: 23348418 DOI: 10.1039/c2cs35384a] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Benoit Coasne
- Institut Charles Gerhardt Montpellier, CNRS (UMR 5253), University Montpellier 2, ENSCM, 8 rue de l'Ecole Normale, 34296 Montpellier, France.
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Coasne B, Ugliengo P. Atomistic model of micelle-templated mesoporous silicas: structural, morphological, and adsorption properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:11131-11141. [PMID: 22762484 DOI: 10.1021/la3022529] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The structural, morphological, and adsorption properties of MCM-41 porous silicas are investigated using a realistic numerical model obtained by means of ab initio calculations [Ugliengo, P.; et al. Adv. Mater.2008, 20, 1]. Simulated X-ray diffraction, small angle neutron scattering, and electronic microscopy for the atomistic model are in good agreement with experimental data. The morphological features are also assessed from chord length distributions and porous volume and specific geometrical surface calculations, etc. The N(2), CO(2), and H(2)O adsorption isotherms in the atomistic model of MCM-41 are also in reasonable agreement with their experimental counterpart. An important finding of the present work is that water forms a film adsorbed on specific hydrophilic regions of the surface while the rest of the surface is depleted in water molecules. This result suggests that the surface of MCM-41 materials is heterogeneous, as it is made up of both hydrophilic and hydrophobic patches. While adsorption and irreversible capillary condensation can be described using the thermodynamical approach by Derjaguin (also known as the Derjaguin-Broekhoff-De Boer model), the Freundlich equation fits nicely the data for reversible and continuous filling in small pores.
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Affiliation(s)
- Benoit Coasne
- Institut Charles Gerhardt Montpellier, UMR 5253 CNRS/UM2/ENSCM/UM1, Montpellier, France.
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Liu Z, Do DD, Nicholson D. A thermodynamic study of the mid-density scheme to determine the equilibrium phase transition in cylindrical pores. MOLECULAR SIMULATION 2012. [DOI: 10.1080/08927022.2011.613383] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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18
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Horikawa T, Do DD, Nicholson D. Capillary condensation of adsorbates in porous materials. Adv Colloid Interface Sci 2011; 169:40-58. [PMID: 21937014 DOI: 10.1016/j.cis.2011.08.003] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 08/26/2011] [Accepted: 08/27/2011] [Indexed: 11/30/2022]
Abstract
Hysteresis in capillary condensation is important for the fundamental study and application of porous materials, and yet experiments on porous materials are sometimes difficult to interpret because of the many interactions and complex solid structures involved in the condensation and evaporation processes. Here we make an overview of the significant progress in understanding capillary condensation and hysteresis phenomena in mesopores that have followed from experiment and simulation applied to highly ordered mesoporous materials such as MCM-41 and SBA-15 over the last few decades.
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Affiliation(s)
- Toshihide Horikawa
- School of Chemical Engineering, University of Queensland, St. Lucia, Qld 4072, Australia
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19
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Liu Z, Herrera L, Nguyen VT, Do DD, Nicholson D. A Monte Carlo scheme based on mid-density in a hysteresis loop to determine equilibrium phase transition. MOLECULAR SIMULATION 2011. [DOI: 10.1080/08927022.2011.578135] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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20
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Wang Y, Do D, Nicholson D. Study of heat of adsorption across the capillary condensation in cylindrical pores. Colloids Surf A Physicochem Eng Asp 2011. [DOI: 10.1016/j.colsurfa.2011.02.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Appell M, Jackson MA, Dombrink-Kurtzman MA. Removal of patulin from aqueous solutions by propylthiol functionalized SBA-15. JOURNAL OF HAZARDOUS MATERIALS 2011; 187:150-156. [PMID: 21269768 DOI: 10.1016/j.jhazmat.2011.01.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 12/14/2010] [Accepted: 01/02/2011] [Indexed: 05/30/2023]
Abstract
Propylthiol functionalized SBA-15 silica was investigated to detoxify aqueous solutions contaminated with the regulated mycotoxin patulin. Micelle templated silicas with a specific pore size were synthetically modified to possess propylthiol groups, a functional group known to form Michael reaction products with the conjugated double bond system of patulin. BET surface area analysis indicated the propylthiol functionalized SBA-15 possesses channels with the pore size of 5.4 nm and a surface area of 345 m(2)g(-1). Elemental analysis indicates the silicon/sulfur ratio to be 10:1, inferring one propylthiol substituent for every ten silica residues. The propylthiol modified SBA-15 was effective at significantly reducing high levels of patulin from aqueous solutions (pH 7.0) in batch sorption assays at room temperature. The material was less effective at lower pH; however heating low pH solutions and apple juice to 60 °C in the presence of propylthiol functionalized SBA-15 significantly reduced the levels of patulin in contaminated samples. Composite molecular models developed by semi-empirical PM3 and empirical force field methods support patulin permeation through the mesoporous channels of propylthiol functionalized SBA-15. Density functional study at the B3LYP/6-31G(d,p) level predicts the proposed patulin adducts formed by reaction with the thiol residues exhibit less electrophilic properties than patulin. It is demonstrated the use of propylthiol functionalized SBA-15 is a viable approach to reduce patulin levels in aqueous solutions, including contaminated apple juice.
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Affiliation(s)
- Michael Appell
- Bacterial Foodborne Pathogens and Mycology Research Unit, United States Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, 1815N University St, Peoria, IL 61604, USA.
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Nakahara S, Tanner DA, Hudson S, Magner E, Redington W, Hodnett K. Defocus image contrast in hexagonally-ordered mesoporous material. Phys Chem Chem Phys 2011; 13:1189-200. [PMID: 21076765 DOI: 10.1039/c0cp01141j] [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
A transmission electron microscope was used to characterize a powder form of hexagonally-ordered mesoporous silica material. The structural symmetry built into this amorphous material allowed one to obtain three characteristic images, i.e. a hexagonal honey-comb structure and wide/narrow parallel lines. These images were found to originate primarily from phase contrast, which changed sensitively with defocusing. To further understand the contrast behaviour of these images, an analytical form of the defocus contrast theory was developed and applied to the simulation of the characteristic wide/narrow parallel line images. The simulation was found to be in good qualitative agreement with experiments, where changes in focus conditions and specimen thickness were predicted to alter the contrast in the resulting parallel-line type images.
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Affiliation(s)
- S Nakahara
- Materials & Surface Science Institute, University of Limerick, Limerick, Ireland
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Coasne B, Czwartos J, Sliwinska-Bartkowiak M, Gubbins KE. Freezing of mixtures confined in silica nanopores: Experiment and molecular simulation. J Chem Phys 2010; 133:084701. [DOI: 10.1063/1.3464279] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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Bruschi L, Mistura G, Liu L, Lee W, Gösele U, Coasne B. Capillary condensation and evaporation in alumina nanopores with controlled modulations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:11894-11898. [PMID: 20491494 DOI: 10.1021/la1011082] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Capillary condensation in nanoporous anodic aluminum oxide presenting not interconnected pores with controlled modulations is studied using adsorption experiments and molecular simulations. Both the experimental and simulation data show that capillary condensation and evaporation are driven by the smallest size of the nanopore (constriction). The adsorption isotherms for the open and closed pores are almost identical if constrictions are added to the system. The latter result implies that the type of pore ending does not matter in modulated pores. Thus, the presence of hysteresis loops observed in adsorption isotherms measured in straight nanopores with closed bottom ends can be explained in terms of geometrical inhomogeneities along the pore axis. More generally, these results provide a general picture of capillary condensation and evaporation in constricted or modulated pores that can be used for the interpretation of adsorption in disordered porous materials.
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Affiliation(s)
- Lorenzo Bruschi
- Dipartimento di Fisica G.Galilei and CNISM, Università di Padova, via Marzolo 8, 35131 Padova, Italy
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Coasne B, Galarneau A, Di Renzo F, Pellenq RJM. Molecular simulation of nitrogen adsorption in nanoporous silica. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:10872-10881. [PMID: 20459091 DOI: 10.1021/la100757b] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
This article reports on a molecular simulation study of nitrogen adsorption and condensation at 77 K in atomistic silica cylindrical nanopores (MCM-41). Two models are considered for the nitrogen molecule and its interaction with the silica substrate. In the "pea" model, the nitrogen molecule is described as a single Lennard-Jones sphere and only Lennard-Jones interactions between the nitrogen molecule and the oxygens atoms of the silica substrate are taken into account. In the "bean" model (TraPPE force field), the nitrogen molecule is composed of two Lennard-Jones sites and a linear array of three charges on the atomic positions and at the center of the nitrogen-nitrogen bond. In the bean model, the interactions between the sites on the nitrogen molecule and the Si, O, and H atoms of the substrate are the sum of the Coulombic and dispersion interactions with a repulsive short-range contribution. The data obtained with the pea and bean models in silica nanopores conform to the typical behavior observed in the experiments for adsorption/condensation in cylindrical MCM-41 nanopores; the adsorbed amount increases continuously in the multilayer adsorption regime until an irreversible jump occurs because of capillary condensation and evaporation of the fluid within the pore. Our results suggest that the pea model can be used for characterization purposes where one is interested in capturing the global experimental behavior upon adsorption and desorption in silica nanopores. However, the bean model is more suitable to investigating the details of the interaction with the surface because this model, which accounts for the partial charges located on the nitrogen atoms of the molecule (quadrupole), allows a description of the specific interactions between this adsorbate and silica surfaces (silanol groups and siloxane bridges) or grafted silica surfaces. In particular, the bean model provides a more realistic picture of nitrogen adsorption in the vicinity of silica surfaces or confined in silica nanopores, where the isosteric heat of adsorption curves show that the nitrogen molecule in this model is sensitive to the surface heterogeneity.
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Affiliation(s)
- B Coasne
- Institut Charles Gerhardt Montpellier, UMR 5253 CNRS/UM2/ENSCM/UM1, ENSCM, 8 rue de l'Ecole Normale, 34296 Montpellier Cedex 05, France.
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Coasne B, Alba-Simionesco C, Audonnet F, Dosseh G, Gubbins KE. Adsorption and structure of benzene on silica surfaces and in nanopores. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:10648-10659. [PMID: 19670890 DOI: 10.1021/la900984z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Grand canonical Monte Carlo simulations are used to study the adsorption of benzene on atomistic silica surfaces and in cylindrical nanopores. The effect of temperature and surface chemistry is addressed by studying the adsorption of benzene at 293 and 323 K on both fully and partially hydroxylated silica surfaces or nanopores. We also consider the adsorption of benzene in a cylindrical nanopore of diameter D=3.6 nm and compare our results with those obtained for planar surfaces. The structure of benzene in the vicinity of the planar surface and confined in the cylindrical nanopore is determined by calculating orientational order parameters and examining positional pair correlation functions. The density profiles of adsorbed benzene reveal the strong layering of the adsorbate, which decays with the distance from the silica surface. At a given temperature and at low pressures, the film adsorbed at the fully hydroxylated silica surface is larger than that for the partially hydroxylated silica surface. This result is due to an increase in the density of silanol groups that induces an increase in the polarity of the silica surface, which becomes more attractive for the adsorbate. Our results also suggest that the benzene molecules prefer an orientation in which their ring is nearly perpendicular to the surface when fully hydroxylated surfaces are considered. When partially hydroxylated surfaces are considered, a second preferential orientation is observed where the benzene ring forms an angle of approximately 50 degrees with the silica surface. In this case, the average orientation of the benzene molecules appears disordered as in the bulk phase. These results suggest that determining the experimental orientation of benzene in the vicinity of a silica surface is a difficult task even when the surface chemistry is known. Capillary condensation in the nanopores involves a transition from a partially filled pore (a thin film adsorbed at the pore surface) to a completely filled pore configuration where the confined liquid coexists at equilibrium with the external gas phase. The disordered orientation of the adsorbed benzene molecules in the case of the partially hydroxylated surface favors the condensation of benzene molecules (the condensation pressure for this substrate is lower than that for the fully hydroxylated surface). Finally, these results are consistent with the structural analysis, showing that (1) benzene tends to relax its liquid structure a little in order to optimize its molecular arrangement near the pore wall and (2) the disordering of the liquid structure induced by the surface becomes stronger as the interaction with the pore wall increases.
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Affiliation(s)
- Benoit Coasne
- Institut Charles Gerhardt Montpellier, UMR 5253 CNRS, Université Montpellier 2, ENSCM, Place Eugene Bataillon, 34095 Montpellier Cedex 05, France.
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