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Leverant CJ, Greathouse JA, Harvey JA, Alam TM. Machine Learning Predictions of Simulated Self-Diffusion Coefficients for Bulk and Confined Pure Liquids. J Chem Theory Comput 2023. [PMID: 37192538 DOI: 10.1021/acs.jctc.2c01040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Diffusion properties of bulk fluids have been predicted using empirical expressions and machine learning (ML) models, suggesting that predictions of diffusion also should be possible for fluids in confined environments. The ability to quickly and accurately predict diffusion in porous materials would enable new discoveries and spur development in relevant technologies such as separations, catalysis, batteries, and subsurface applications. In this work, we apply artificial neural network (ANN) models to predict the simulated self-diffusion coefficients of real liquids in both bulk and pore environments. The training data sets were generated from molecular dynamics (MD) simulations of Lennard-Jones particles representing a diverse set of 14 molecules ranging from ammonia to dodecane over a range of liquid pressures and temperatures. Planar, cylindrical, and hexagonal pore models consisted of walls composed of carbon atoms. Our simple model for these liquids was primarily used to generate ANN training data, but the simulated self-diffusion coefficients of bulk liquids show excellent agreement with experimental diffusion coefficients. ANN models based on simple descriptors accurately reproduced the MD diffusion data for both bulk and confined liquids, including the trend of increased mobility in large pores relative to the corresponding bulk liquid.
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Affiliation(s)
- Calen J Leverant
- Nanoscale Sciences Department, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Jeffery A Greathouse
- Nuclear Waste Disposal Research & Analysis Department, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Jacob A Harvey
- Geochemistry Department, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Todd M Alam
- Department of Organic Materials Science, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
- ACC Consulting New Mexico, Cedar Crest, New Mexico 87008, United States
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2
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Mulla T, Pellenq RJM, Ulm FJ. Fluctuation-based fracture mechanics of heterogeneous materials. Phys Rev E 2022; 106:065003. [PMID: 36671134 DOI: 10.1103/physreve.106.065003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 11/27/2022] [Indexed: 06/17/2023]
Abstract
We present results of a hybrid analytical-simulation investigation of the fracture resistance of heterogeneous materials. We show that bond-energy fluctuations sampled by Monte Carlo simulations in the semigrand canonical ensemble provide a means to rationalize the complexity of heterogeneous fracture processes, encompassing probability and percolation theories of fracture. For a number of random and textured model materials, we derive upper and lower bounds of fracture resistance and link bond fracture fluctuations to statistical descriptors of heterogeneity, such as two-point correlation functions, to identify the origin of toughening mechanisms. This includes a shift from short- to long-range interactions of bond fracture processes in random systems to the transition from critical to subcritical bond fracture percolation in textured materials and the activation of toughness reserves at compliant interfaces. Induced by elastic mismatch, they connect to a number of disparate experimental observations, including toughening of brittle solids by deformable polymers or organics in, e.g., gas shale, nacre; stress-induced transformational toughening in ceramics; and toughening of sparse elastic networks in hydrogels, to name a few.
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Affiliation(s)
- T Mulla
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - R J-M Pellenq
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- MIT-CNRS-AMU Joint Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Physics, Georgetown University, Washington, DC, USA
| | - F-J Ulm
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- MIT-CNRS-AMU Joint Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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3
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Vellamarthodika S, Gautam S. Role of orientational disorder in ZSM-22 in the adsorption of SO 2. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2117663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- Sadique Vellamarthodika
- Positron Foundation for Science and Innovation, CITTIC, Cochin University of Science and Technology, Cochin, India
| | - Siddharth Gautam
- School of Earth Sciences, The Ohio State University, Columbus, OH, USA
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4
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Advances in the Application of Vegetable-Oil-Based Cutting Fluids to Sustainable Machining Operations—A Review. LUBRICANTS 2022. [DOI: 10.3390/lubricants10040069] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Scientists and tribologists are currently exploring sustainable and inexhaustible lubricants as a result of increased awareness of environmental and health-related issues. Vegetable oils are being investigated as a potential form of environmentally friendly cutting fluids due to their excellent renewability, biodegradability, and lubricating performance. This report provides an overview of different vegetable oils used as cutting fluids in the machining of engineering materials. The effects of virgin vegetable oils, emulsified vegetable-based oils, and vegetable-oil-based nano-cutting fluids on the cutting force, the surface finish of machined parts, the tool wear, and the temperature of the cutting area were surveyed critically. Compared to mineral-oil-based cutting fluids, studies have demonstrated that vegetable-oil-based cutting fluids meet cleaner manufacturing standards with good or better efficiency.
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5
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Liu Z, Mao Z, Feng X, Liu Y, Zheng X, Li S, Zhu H, Peng C, Yang C. Understanding the Diffusion Properties of Sulfur-Containing Compounds in Mesoporous Alumina: A Molecular Dynamics Study. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.1c04934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhe Liu
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, China
| | - Zhiwei Mao
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, China
| | - Xiang Feng
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, China
| | - Yibin Liu
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, China
| | - Xiuhui Zheng
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, China
| | - Shuo Li
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, China
| | - Huihong Zhu
- Dalian Research Institute of Petroleum and Petrochemicals, SINOPEC, Dalian 116045, China
| | - Chong Peng
- Dalian Research Institute of Petroleum and Petrochemicals, SINOPEC, Dalian 116045, China
| | - Chaohe Yang
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, China
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6
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Predicting adsorption and separation performance indicators of Xe/Kr in metal-organic frameworks via a precursor-based neural network model. Chem Eng Sci 2021. [DOI: 10.1016/j.ces.2021.116772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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7
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Berthonneau J, Grauby O, Jolivet IC, Gelin F, Chanut N, Magnin Y, Pellenq RJM, Ferry D. Nanoscale Accessible Porosity as a Key Parameter Depicting the Topological Evolution of Organic Porous Networks. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:5464-5474. [PMID: 33909979 DOI: 10.1021/acs.langmuir.0c03519] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A significant part of the hydrocarbons contained in source rocks remains confined within the organic matter-called kerogen-from where they are generated. Understanding the sorption and transport properties of confined hydrocarbons within the kerogens is, therefore, paramount to predict production. Specifically, knowing the impact of thermal maturation on the evolution of the organic porous network is key. Here, we propose an experimental procedure to study the interplay between the chemical evolution and the structural properties of the organic porous network at the nanometer scale. First, the organic porous networks of source rock samples, covering a significant range of natural thermal maturation experienced by the Vaca Muerta formation (Neuquén Basin, Argentina), are physically reconstructed using bright-field electron tomography. Their structural description allows us to measure crucial parameters such as the porosity, specific pore volume and surface area, aperture and cavity size distributions, and constriction. In addition, a model-free computation of the topological properties (effective porosity, connectivity, and tortuosity) is conducted. Overall, we document a general increase of the specific pore volume with thermal maturation. This controls the topological features depicting increasing accessibility to alkane molecules, sensed by the evolution of the effective porosity. Collectively, our results highlight the input of bright-field electron tomography in the study of complex disordered amorphous porous media, especially to describe the interplay between the structural features and transport properties of confined fluids.
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Affiliation(s)
| | - Olivier Grauby
- Aix-Marseille Univ, CNRS, CINaM, 13009 Marseille, France
| | - Isabelle C Jolivet
- Total E&P Research & Development, CSTJF, Avenue Larribau, 64018 Pau Cedex, France
| | - François Gelin
- Total E&P Research & Development, CSTJF, Avenue Larribau, 64018 Pau Cedex, France
| | - Nicolas Chanut
- MultiScale Materials Science for Energy and Environment, CNRS/MIT/Aix-Marseille University Joint Laboratory at Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Yann Magnin
- MultiScale Materials Science for Energy and Environment, CNRS/MIT/Aix-Marseille University Joint Laboratory at Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Roland J-M Pellenq
- Aix-Marseille Univ, CNRS, CINaM, 13009 Marseille, France
- MultiScale Materials Science for Energy and Environment, CNRS/MIT/Aix-Marseille University Joint Laboratory at Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Daniel Ferry
- Aix-Marseille Univ, CNRS, CINaM, 13009 Marseille, France
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8
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Mulla T, Moeini S, Ioannidou K, Pellenq RJM, Ulm FJ. Phase diagram of brittle fracture in the semi-grand-canonical ensemble. Phys Rev E 2021; 103:013003. [PMID: 33601550 DOI: 10.1103/physreve.103.013003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 12/21/2020] [Indexed: 11/07/2022]
Abstract
We present a simulation method to assess the quasistatic fracture resistance of materials. Set within a semi-grand-canonical Monte Carlo (SGCMC) simulation environment, an auxiliary field-the bond rupture potential-is introduced to generate a sufficiently large number of possible microstates in the semi-grand-canonical ensemble, and associated energy and bond fluctuations. The SGCMC approach permits identifying the full phase diagram of brittle fracture for harmonic and nonharmonic bond potentials, analogous to the gas-liquid phase diagram, with the equivalent of a liquidus line ending in a critical point. The phase diagram delineates a solid phase, a fractured phase, and a gas phase, and provides clear evidence of a first-order phase transition intrinsic to fracture. Moreover, energy and bond fluctuations generated with the SGCMC approach permit determination of the maximum energy dissipation associated with bond rupture, and hence of the fracture resistance of a widespread range of materials that can be described by bond potentials.
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Affiliation(s)
- T Mulla
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - S Moeini
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - K Ioannidou
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,MIT-CNRS-AMU Joint Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,Laboratoire de Mcanique et Gnie Civil, CNRS Universit de Montpellier, 34090 Montpellier, France
| | - R J-M Pellenq
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,MIT-CNRS-AMU Joint Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,Department of Physics, Georgetown University, Washington DC 20057, USA
| | - F-J Ulm
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,MIT-CNRS-AMU Joint Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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9
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Monfared S, Zhou T, Andrade JE, Ioannidou K, Radjaï F, Ulm FJ, Pellenq RJM. Effect of Confinement on Capillary Phase Transition in Granular Aggregates. PHYSICAL REVIEW LETTERS 2020; 125:255501. [PMID: 33416387 DOI: 10.1103/physrevlett.125.255501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 11/16/2020] [Indexed: 06/12/2023]
Abstract
Using a 3D mean-field lattice-gas model, we analyze the effect of confinement on the nature of capillary phase transition in granular aggregates with varying disorder and their inverse porous structures obtained by interchanging particles and pores. Surprisingly, the confinement effects are found to be much less pronounced in granular aggregates as opposed to porous structures. We show that this discrepancy can be understood in terms of the surface-surface correlation length with a connected path through the fluid domain, suggesting that this length captures the true degree of confinement. We also find that the liquid-gas phase transition in these porous materials is of second order nature near capillary critical temperature, which is shown to represent a true critical temperature, i.e., independent of the degree of disorder and the nature of the solid matrix, discrete or continuous. The critical exponents estimated here from finite-size scaling analysis suggest that this transition belongs to the 3D random field Ising model universality class as hypothesized by F. Brochard and P.G. de Gennes, with the underlying random fields induced by local disorder in fluid-solid interactions.
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Affiliation(s)
- Siavash Monfared
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125, USA
| | - Tingtao Zhou
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125, USA
| | - José E Andrade
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125, USA
| | - Katerina Ioannidou
- CNRS, University of Montpellier, LMGC, 163 rue Auguste Broussonnet F-34090 Montpellier, France
- MultiScale Material Science for Energy and Environment UMI 3466 CNRS-MIT-Aix-Marseille Université Joint Laboratory, Cambridge, Massachusetts 02139, USA
| | - Farhang Radjaï
- CNRS, University of Montpellier, LMGC, 163 rue Auguste Broussonnet F-34090 Montpellier, France
| | - Franz-Josef Ulm
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Roland J-M Pellenq
- MultiScale Material Science for Energy and Environment UMI 3466 CNRS-MIT-Aix-Marseille Université Joint Laboratory, Cambridge, Massachusetts 02139, USA
- Department of Physics, Georgetown University, Washington, D.C. 20057, USA
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10
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Hogan A, Space B. Next-Generation Accurate, Transferable, and Polarizable Potentials for Material Simulations. J Chem Theory Comput 2020; 16:7632-7644. [PMID: 33251798 DOI: 10.1021/acs.jctc.0c00837] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
PHAHST (potentials with high accuracy, high speed, and transferability) intermolecular potential energy functions have been developed from first principles for H2, N2, the noble gases, and a metal-organic material, HKUST-1. The potentials are designed from the outset to be transferable to heterogeneous environments including porous materials, interfaces, and material simulations. This is accomplished by theoretically justified choices for all functional forms, parameters, and mixing rules, including explicit polarization in every environment and fitting to high quality electronic structure calculations using methods that are tractable for real systems. The models have been validated in neat systems by comparison to second virial coefficients and bulk pressure-density isotherms. For inhomogeneous applications, our main target, comparisons are presented to previously published experimental studies on the metal-organic material HKUST-1 including adsorption, isosteric heats of adsorption, binding site locations, and binding site energies. A systematic prescription is provided for developing compatible potentials for additional small molecules and materials. The resulting models are recommended for use in complex heterogeneous simulations where existing potentials may be inadequate.
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Affiliation(s)
- Adam Hogan
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., CHE205, Tampa, Florida 33620-5250, United States
| | - Brian Space
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., CHE205, Tampa, Florida 33620-5250, United States
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11
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Dang Y, Yao Y, Liu Y, Wei B, Feng X, Chen X, Yang C. Diffusion properties of aromatic hydrocarbons in mesoporous alumina: A molecular dynamics study. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2019.04.023] [Citation(s) in RCA: 7] [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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12
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Zhou T, Ioannidou K, Masoero E, Mirzadeh M, Pellenq RJM, Bazant MZ. Capillary Stress and Structural Relaxation in Moist Granular Materials. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:4397-4402. [PMID: 30798608 DOI: 10.1021/acs.langmuir.8b03400] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A numerical and theoretical framework to address the poromechanical effect of capillary stress in complex mesoporous materials is proposed and exemplified for water sorption in cement. We first predict the capillary condensation/evaporation isotherm using lattice-gas simulations in a realistic nanogranular cement model. A phase-field model to calculate moisture-induced capillary stress is then introduced and applied to cement at different water contents. We show that capillary stress is an effective mechanism for eigenstress relaxation in granular heterogeneous porous media, which contributes to the durability of cement.
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Affiliation(s)
| | | | - Enrico Masoero
- School of Engineering , Newcastle University , Newcastle upon Tyne NE1 7RU , U.K
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13
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Yang X, Zhang C, Jiang L, Li Z, Liu Y, Wang H, Xing Y, Yang RT. Molecular Simulation of Naphthalene, Phenanthrene, and Pyrene Adsorption on MCM-41. Int J Mol Sci 2019; 20:ijms20030665. [PMID: 30717495 PMCID: PMC6387010 DOI: 10.3390/ijms20030665] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 01/25/2019] [Accepted: 01/31/2019] [Indexed: 12/14/2022] Open
Abstract
The adsorption of three typical polycyclic aromatic hydrocarbons (PAHs), naphthalene, phenanthrene, and pyrene with different ring numbers, on a common mesoporous material (MCM-41) was simulated based on a well-validated model. The adsorption equilibriums (isotherms), states (angle distributions and density profiles), and interactions (radial distribution functions) of three PAHs within the mesopores were studied in detail. The results show that the simulated isotherms agreed with previous experimental results. Each of the PAHs with flat molecules showed an adsorption configuration that was parallel to the surface of the pore, in the following order according to the degree of arrangement: pyrene (Pyr) > phenanthrene (Phe) > naphthalene (Nap). In terms of the interaction forces, there were no hydrogen bonds or other strong polar forces between the PAHs and MCM-41, and the O⁻H bond on the adsorbent surface had a unique angle in relation to the PAH molecular plane. The polarities of different H atoms on the PAHs were roughly the same, while those of the C atoms on the PAHs decreased from the molecular centers to the edges. The increasing area of the π-electron plane on the PAHs with the increasing ring number could lead to stronger adsorption interactions, and thus a shorter distance between the adsorbate and the adsorbent.
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Affiliation(s)
- Xiong Yang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.
- Beijing Higher Institution Engineering Research Center of Energy Conservation and Environmental Protection, Beijing 100083, China.
| | - Chuanzhao Zhang
- College of Biochemical Engineering, Beijing Union University, Beijing 100023, China.
| | - Lijun Jiang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.
| | - Ziyi Li
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.
- Beijing Higher Institution Engineering Research Center of Energy Conservation and Environmental Protection, Beijing 100083, China.
| | - Yingshu Liu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.
- Beijing Higher Institution Engineering Research Center of Energy Conservation and Environmental Protection, Beijing 100083, China.
| | - Haoyu Wang
- College of Biochemical Engineering, Beijing Union University, Beijing 100023, China.
| | - Yi Xing
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.
- Beijing Higher Institution Engineering Research Center of Energy Conservation and Environmental Protection, Beijing 100083, China.
| | - Ralph T Yang
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
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14
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Mesoscale structure, mechanics, and transport properties of source rocks' organic pore networks. Proc Natl Acad Sci U S A 2018; 115:12365-12370. [PMID: 30442660 PMCID: PMC6298101 DOI: 10.1073/pnas.1808402115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In source rocks, natural hydrocarbons are generated from organic matter dispersed in a fine-grained mineral matrix. The potential recovery of hydrocarbons is therefore influenced by the geometry of the organic hosted porous networks. Here, the three-dimensional structures of such networks are revealed using electron tomography with a subnanometer resolution. The reconstructions are first characterized in terms of morphology and topology and then used to build a multiscale simulation tool to study the mechanics and the transport properties of confined fluids. Our results offer evidence of the prevalent role of connected nanopores, which subsequently constitutes a material limit for long-term hydrocarbon production. Organic matter is responsible for the generation of hydrocarbons during the thermal maturation of source rock formation. This geochemical process engenders a network of organic hosted pores that governs the flow of hydrocarbons from the organic matter to fractures created during the stimulation of production wells. Therefore, it can be reasonably assumed that predictions of potentially recoverable confined hydrocarbons depend on the geometry of this pore network. Here, we analyze mesoscale structures of three organic porous networks at different thermal maturities. We use electron tomography with subnanometric resolution to characterize their morphology and topology. Our 3D reconstructions confirm the formation of nanopores and reveal increasingly tortuous and connected pore networks in the process of thermal maturation. We then turn the binarized reconstructions into lattice models including information from atomistic simulations to derive mechanical and confined fluid transport properties. Specifically, we highlight the influence of adsorbed fluids on the elastic response. The resulting elastic energy concentrations are localized at the vicinity of macropores at low maturity whereas these concentrations present more homogeneous distributions at higher thermal maturities, due to pores’ topology. The lattice models finally allow us to capture the effect of sorption on diffusion mechanisms with a sole input of network geometry. Eventually, we corroborate the dominant impact of diffusion occurring within the connected nanopores, which constitute the limiting factor of confined hydrocarbon transport in source rocks.
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15
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Gommes CJ, Roberts AP. Stochastic analysis of capillary condensation in disordered mesopores. Phys Chem Chem Phys 2018; 20:13646-13659. [PMID: 29737990 DOI: 10.1039/c8cp01628c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Most mesoporous materials of practical interest are inherently disordered, which has a significant impact on the condensation and evaporation of vapours in their pores. Traditionally, the effect of disorder is theoretically analyzed in a perturbative approach whereby slight elements of disorder (constriction, corrugation) are added to geometrically ideal pores. We propose an alternative approach, which consists of using a stochastic geometrical model to describe both the porous material and the condensate within the pores. This is done through a multiphase generalisation of the standard Gaussian random field model of disordered materials. The model parameters characterising the condensate provide a low-dimensional approximation of its configuration space, and we use a Derjaguin-Broekhoff-de Boer approximation to calculate the free-energy landscape. Our analysis notably questions the existence of vapour-like metastable states in realistically disordered mesoporous materials. Beyond capillary condensation, our general methodology is applicable to a broad array of confined phenomena.
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Affiliation(s)
- Cedric J Gommes
- Department of Chemical Engineering, University of Liège, Allée du Six Août, 3, B-4000 Liège, Belgium.
| | - Anthony P Roberts
- School of Mathematics and Physics, The University of Queensland, Brisbane, QLD 4072, Australia
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16
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Tong M, Lan Y, Yang Q, Zhong C. Exploring the structure-property relationships of covalent organic frameworks for noble gas separations. Chem Eng Sci 2017. [DOI: 10.1016/j.ces.2017.05.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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17
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18
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An R, Huang L, Mineart KP, Dong Y, Spontak RJ, Gubbins KE. Adhesion and friction in polymer films on solid substrates: conformal sites analysis and corresponding surface measurements. SOFT MATTER 2017; 13:3492-3505. [PMID: 28422244 DOI: 10.1039/c7sm00261k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this work, we present a statistical mechanical analysis to elucidate the molecular-level factors responsible for the static and dynamic properties of polymer films. This analysis, which we term conformal sites theory, establishes that three dimensionless parameters play important roles in determining differences from bulk behavior for thin polymer films near to surfaces: a microscopic wetting parameter, αwx, defined as the ratio of polymer-substrate interaction to polymer-polymer interaction; a dimensionless film thickness, H*; and dimensionless temperature, T*. The parameter αwx introduced here provides a more fundamental measure of wetting than previous metrics, since it is defined in terms of intermolecular forces and the atomic structure of the substrate, and so is valid at the nanoscale for gas, liquid or solid films. To test this theoretical analysis, we also report atomic force microscopy measurements of the friction coefficient (μ), adhesion force (FA) and glass transition temperature (Tg) for thin films of two polymers, poly(methyl methacrylate) (PMMA) and polystyrene (PS), on two planar substrates, graphite and silica. Both the friction coefficient and the glass transition temperature are found to increase as the film thickness decreases, and this increase is more pronounced for the graphite than for the silica surface. The adhesion force is also greater for the graphite surface. The larger effects encountered for the graphite surface are attributed to the fact that the microscopic wetting parameter, αwx, is larger for graphite than for silica, indicating stronger attraction of polymer chains to the graphite surface.
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Affiliation(s)
- Rong An
- Herbert Gleiter Institute of Nanoscience, Nanjing University of Science & Technology, Nanjing 210094, P. R. China and Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Liangliang Huang
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, OK 73019, USA
| | - Kenneth P Mineart
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Yihui Dong
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China
| | - Richard J Spontak
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA. and Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Keith E Gubbins
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
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Abstract
Strength and other mechanical properties of cement and concrete rely upon the formation of calcium-silicate-hydrates (C-S-H) during cement hydration. Controlling structure and properties of the C-S-H phase is a challenge, due to the complexity of this hydration product and of the mechanisms that drive its precipitation from the ionic solution upon dissolution of cement grains in water. Departing from traditional models mostly focused on length scales above the micrometer, recent research addressed the molecular structure of C-S-H. However, small-angle neutron scattering, electron-microscopy imaging, and nanoindentation experiments suggest that its mesoscale organization, extending over hundreds of nanometers, may be more important. Here we unveil the C-S-H mesoscale texture, a crucial step to connect the fundamental scales to the macroscale of engineering properties. We use simulations that combine information of the nanoscale building units of C-S-H and their effective interactions, obtained from atomistic simulations and experiments, into a statistical physics framework for aggregating nanoparticles. We compute small-angle scattering intensities, pore size distributions, specific surface area, local densities, indentation modulus, and hardness of the material, providing quantitative understanding of different experimental investigations. Our results provide insight into how the heterogeneities developed during the early stages of hydration persist in the structure of C-S-H and impact the mechanical performance of the hardened cement paste. Unraveling such links in cement hydrates can be groundbreaking and controlling them can be the key to smarter mix designs of cementitious materials.
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Liu Z, Wu Y, Liu B, Oh SC, Fan W, Qian Y, Xi H. Tuning the adsorption and separation properties of noble gases and N2 in CuBTC by ligand functionalization. RSC Adv 2016. [DOI: 10.1039/c6ra08778g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The Grand Canonical Monte Carlo method was used to investigate adsorption and separation properties of noble gas and N2 mixtures on CuBTCs, functionalized with different groups, including amino, hydroxyl and fluorine groups.
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Affiliation(s)
- Zewei Liu
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou 510640
- PR China
| | - Ying Wu
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou 510640
- PR China
| | - Baoyu Liu
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou 510640
- PR China
| | - Su Chen Oh
- Department of Chemical and Biomolecular Engineering
- University of Maryland
- College Park
- Maryland 20742
- USA
| | - Wei Fan
- Department of Chemical Engineering
- University of Massachusetts Amherst
- Amherst
- USA
| | - Yu Qian
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou 510640
- PR China
| | - Hongxia Xi
- School of Chemistry and Chemical Engineering
- South China University of Technology
- Guangzhou 510640
- PR China
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21
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Sizova AA, Sizov VV, Brodskaya EN. Adsorption of CO2/CH4 and CO2/N2 mixtures in SBA-15 and CMK-5 in the presence of water: A computer simulation study. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2015.03.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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22
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Greathouse JA, Teich-McGoldrick SL, Allendorf MD. Molecular simulation of size-selective gas adsorption in idealised carbon nanotubes. MOLECULAR SIMULATION 2015. [DOI: 10.1080/08927022.2015.1007054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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23
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Tavakoli F, Kavehpour HP. Cold-induced spreading of water drops on hydrophobic surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:2120-2126. [PMID: 25631237 DOI: 10.1021/la503620a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Superhydrophobic surfaces are characterized by their peculiarities, such as water-repellent, anti-icing, and freezing-delay properties. Wetting dynamics of deposited water drops on cooling hydrophobic surfaces, which directly affects the aforementioned properties, has not been studied thoroughly. Here, water drops are cooled on different hydrophobic surfaces in a controlled environment. During the cooling process, a significant increase in the drop footprint and decrease in the apparent contact angle are observed because of premature and capillary condensation, followed by thin water film formation adjacent to the solid-liquid-gas line. The water thin film propagates on the hydrophobic substrates radially away from the trijunction, followed by spreading of the drop on the film, which was experimentally validated through high-speed visualization. In addition, the roles of physical variables, such as the substrate temperature, humidity of surrounding air, types of hydrophobic surfaces, surface roughness, and drop volume, on post-spreading shape are investigated experimentally.
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Affiliation(s)
- Faryar Tavakoli
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles (UCLA) , Los Angeles, California 90024, United States
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24
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Falk KI, Coasne BA, Pellenq RJM. Effect of temperature on adsorption of mixtures in porous materials. MOLECULAR SIMULATION 2013. [DOI: 10.1080/08927022.2013.852192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Kerstyn I. Falk
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Benoit A. Coasne
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- Multi-Scale Materials Science for Energy and Environment, The Joint CNRS-MIT Laboratory, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- Institut Charles Gerhardt Montpellier, CNRS and University of Montpellier II, Montpellier, France
| | - Roland J.-M. Pellenq
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- Multi-Scale Materials Science for Energy and Environment, The Joint CNRS-MIT Laboratory, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- Centre Interdisciplinaire des Nanosciences de Marseille, CNRS and Aix-Marseille University, Marseille, France
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25
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Nguyen PT, Do D, Nicholson D. Pore connectivity and hysteresis in gas adsorption: A simple three-pore model. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2013.03.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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26
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Palmer JC, Coasne B, Śliwinska-Bartkowiak M, Jackson G, Müller EA, Gubbins KE. On the molecular origin of high-pressure effects in nanoconfinement: The role of surface chemistry and roughness. J Chem Phys 2013; 139:144701. [DOI: 10.1063/1.4824125] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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27
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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: 33] [Impact Index Per Article: 3.0] [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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28
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Effect of surface functionalities on gas adsorption in microporous carbons: a grand canonical Monte Carlo study. ADSORPTION 2013. [DOI: 10.1007/s10450-013-9507-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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29
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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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30
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Parkes MV, Staiger CL, Perry IV JJ, Allendorf MD, Greathouse JA. Screening metal–organic frameworks for selective noble gas adsorption in air: effect of pore size and framework topology. Phys Chem Chem Phys 2013; 15:9093-106. [DOI: 10.1039/c3cp50774b] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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31
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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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32
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Gommes CJ. Adsorption, capillary bridge formation, and cavitation in SBA-15 corrugated mesopores: a Derjaguin-Broekhoff-de Boer analysis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:5101-5115. [PMID: 22324828 DOI: 10.1021/la2051228] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A Derjaguin-Broekhoff-de Boer analysis of adsorption and desorption in SBA-15 mesoporous silica is presented, using realistic geometrical models that account for the pore corrugation in these materials. The model parameters are derived from independent electron tomography and small-angle scattering characterization. A geometrical characteristic of the pore that is found to be important for adsorption is the corrugation length, l(C), which describes the longitudinal size of the geometrical defects along a given pore. Capillary bridges are possible only for large values of l(C). The results are explained in terms of two spinodal and two equilibrium pressures, characterizing the wide and the narrow sections of the pores. Simplified analytical expressions are obtained, which provide necessary conditions for bridge formation and for cavitation in terms of the radii of the narrow and wide sections of the pores, as well as of l(C). Quite generally, the results show that the deviation of the pore shape from that of ideal cylinders is key to understanding adsorption and desorption in corrugated mesopores, notably in SBA-15.
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Affiliation(s)
- Cedric J Gommes
- Department of Chemical Engineering, University of Liège, Liège, Belgium.
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33
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Ho LN, Pellitero JP, Porcheron F, Pellenq RJM. Enhanced CO2 solubility in hybrid MCM-41: molecular simulations and experiments. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:8187-97. [PMID: 21639400 DOI: 10.1021/la2012765] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Grand canonical Monte Carlo simulations are performed in a hybrid adsorbent model in order to interpret the CO(2) solubility behavior. The hybrid adsorbent is prepared by confining a physical solvent (OMCTS) into the pores of a mimetic MCM-41 solid support. As a result, simulated adsorption isotherms of CO(2) nicely match the experimental data for three distinctive systems: bulk solvent, raw MCM-41, and hybrid MCM-41. The microscopic mechanisms underlying the apparition of enhanced solubility are then clearly identified. In fact, the presence of solvent molecules favors the layering of CO(2) molecules within the pores; therefore, the CO(2) solubility in the hybrid adsorbent markedly increases in comparison to that found in the raw adsorbent as well as in the bulk solvent. In addition, a good understanding of confined solvents' properties and solid surface structures is essential to fully evaluate the efficiency of hybrid adsorbents in capturing CO(2). The sorbent-solid interactions along with the solvent molecular size's impact on CO(2) solubility are therefore investigated in this study. We found that an ideal hybrid system should possess a weak solvent-solid interaction but a strong solvent-CO(2) interaction. Besides, an optimal solvent size is obtained for the enhanced CO(2) solubility in the hybrid system. According to the simulation results, the solvent layer builds pseudomicropores inside the mesoporous MCM-41, enabling more CO(2) molecules to be absorbed under the greater influence of spatial confinement and surface interaction. In addition, the molecular sieving effect is clearly observed in the case of larger solvent molecular sizes.
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Affiliation(s)
- Linh Ngoc Ho
- IFP Energies nouvelles, Rond-Point de l'Échangeur de Solaize, BP 3, 69360 Solaize, France
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34
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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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35
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Affiliation(s)
- Alberto Striolo
- School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, OK 73019, U.S.A
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36
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Coasne B, Pikunic JP, Pellenq RJM, Gubbins KE. Comparison between Adsorption in Pores of a Simple Geometry and Realistic Models of Porous Materials. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-790-p8.5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTWe study, by means of Grand Canonical Monte Carlo simulations, the effect of disorder in pore morphology and topology on adsorption of simple fluids at 77 K. We consider the case of microporous carbons and mesoporous silicas. For both systems, we found that morphological and topological disorder affects the adsorption isotherm. Consequently, we show that complex porous networks cannot be modeled as a collection of unconnected pores of simple geometry. In the case of microporous carbons, the isosteric heat of adsorption for disordered systems differs significantly from that obtained for an assembly of unconnected slit pores. In contrast, the isosteric heat of adsorption for the disordered mesoporous silica sample compares reasonably well with that observed for a silica material having regular cylindrical pores.
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37
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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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38
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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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39
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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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40
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Bhattacharya S, Coasne B, Hung FR, Gubbins KE. Modeling micelle-templated mesoporous material SBA-15: atomistic model and gas adsorption studies. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:5802-5813. [PMID: 19099416 DOI: 10.1021/la801560e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report the development of a realistic molecular model for mesoporous silica SBA-15, which includes both the large cylindrical mesopores and the smaller micropores in the pore walls. The methodology for modeling the SBA-15 structure involves molecular and mesoscale simulations combined with geometrical interpolation techniques. First, a mesoscale model is prepared by mimicking the synthesis process using lattice Monte Carlo simulations. The main physical features of this mesoscale pore model are then carved out of an atomistic silica block; both the mesopores and the micropores are incorporated from the mimetic simulations. The calculated pore size distribution, surface area, and simulated TEM images of the model structure are in good agreement with those obtained from experimental samples of SBA-15. We then investigate the adsorption of argon in this structure using Grand Canonical Monte Carlo (GCMC) simulations. The adsorption results for our SBA-15 model are compared with those for a similar model that does not include the micropores; we also compare with results obtained in a regular cylindrical pore. The simulated adsorption isotherm for the SBA-15 model shows semiquantitative agreement with the experimental isotherm for a SBA-15 sample having a similar pore size. We observe that the presence of the micropores leads to increased adsorption at low pressure compared to the case of a model without micropores in the pore walls. At higher pressures, for all models, the filling proceeds via the monolayer-multilayer adsorption on the mesopore surface followed by capillary condensation, which is mainly controlled by the mesopore diameter and is not influenced by the presence of the micropores.
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Affiliation(s)
- Supriyo Bhattacharya
- Center for High Performance Computing and Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, USA
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41
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Pellenq RJM, Coasne B, Denoyel RO, Coussy O. Simple phenomenological model for phase transitions in confined geometry. 2. Capillary condensation/evaporation in cylindrical mesopores. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:1393-1402. [PMID: 19138076 DOI: 10.1021/la8020244] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A simple phenomenological model that describes capillary condensation and evaporation of pure fluids confined in cylindrical mesopores is presented. Following the work of Celestini (Celestini, F. Phys. Lett. A 1997, 228, 84), the free energy density of the system is derived using interfacial tensions and a corrective term that accounts for the interaction coupling between the vapor/adsorbed liquid and the adsorbed liquid/adsorbent interfaces. This corrective term is shown to be consistent with the Gibbs adsorption isotherm and assessed by standard adsorption tests. This model reveals that capillary condensation and evaporation are metastable and equilibrium processes, respectively, hence exhibiting the existence of a hysteresis loop inadsorption/desorption isotherm that is well-known in experiment. We extend the phenomenological model of Celestini to give a quantitative description of adsorption on the pore wall and hysteresis width evolution with temperature and confinement. Direct quantitative comparison is made with experimental data for confined argon. Used as a characterizing tool, this integrated model allows in a single fit of an experimental adsorption/desorption isotherm assessing essential characterization data such as the specific surface area, pore volume, and mean pore size.
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Affiliation(s)
- Roland J-M Pellenq
- Centre Interdisciplinaire des Nanosciences de Marseille, CINaM, UPR CNRS 3118, Campus de Luminy, 13288 Marseille Cedex 09, France.
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42
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Coasne B, Mezy A, Pellenq RJM, Ravot D, Tedenac JC. Zinc Oxide Nanostructures Confined in Porous Silicas. J Am Chem Soc 2009; 131:2185-98. [PMID: 19199634 DOI: 10.1021/ja806666n] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Benoit Coasne
- Institut Charles Gerhardt Montpellier, UMR 5253 CNRS, Université Montpellier 2, ENSCM, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77, Massachusetts Avenue, Cambridge, Massachusetts 02139, and Centre Interdisciplinaire des Nanosciences de Marseille, UPR 3118 CNRS, Campus de Luminy, 13288 Marseilles, France
| | - Aude Mezy
- Institut Charles Gerhardt Montpellier, UMR 5253 CNRS, Université Montpellier 2, ENSCM, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77, Massachusetts Avenue, Cambridge, Massachusetts 02139, and Centre Interdisciplinaire des Nanosciences de Marseille, UPR 3118 CNRS, Campus de Luminy, 13288 Marseilles, France
| | - R. J. M. Pellenq
- Institut Charles Gerhardt Montpellier, UMR 5253 CNRS, Université Montpellier 2, ENSCM, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77, Massachusetts Avenue, Cambridge, Massachusetts 02139, and Centre Interdisciplinaire des Nanosciences de Marseille, UPR 3118 CNRS, Campus de Luminy, 13288 Marseilles, France
| | - D. Ravot
- Institut Charles Gerhardt Montpellier, UMR 5253 CNRS, Université Montpellier 2, ENSCM, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77, Massachusetts Avenue, Cambridge, Massachusetts 02139, and Centre Interdisciplinaire des Nanosciences de Marseille, UPR 3118 CNRS, Campus de Luminy, 13288 Marseilles, France
| | - J. C. Tedenac
- Institut Charles Gerhardt Montpellier, UMR 5253 CNRS, Université Montpellier 2, ENSCM, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77, Massachusetts Avenue, Cambridge, Massachusetts 02139, and Centre Interdisciplinaire des Nanosciences de Marseille, UPR 3118 CNRS, Campus de Luminy, 13288 Marseilles, France
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Coasne B, Di Renzo F, Galarneau A, Pellenq RJM. Adsorption of simple fluid on silica surface and nanopore: effect of surface chemistry and pore shape. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:7285-7293. [PMID: 18522440 DOI: 10.1021/la800567g] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This paper reports a molecular simulation study on the adsorption of simple fluids (argon at 77 K) on hydroxylated silica surfaces and nanopores. The effect of surface chemistry is addressed by considering substrates with either partially or fully hydroxylated surfaces. We also investigate the effect of pore shape on adsorption and capillary condensation by comparing the results for cylindrical and hexagonal nanopores having equivalent sections (i.e., equal section areas). Due to the increase in the polarity of the surface with the density of OH groups, the adsorbed amounts for fully hydroxylated surfaces are found to be larger than those for partially hydroxylated surfaces. Both the adsorption isotherms for the cylindrical and hexagonal pores conform to the typical behavior observed in the experiments for adsorption/condensation in cylindrical nanopores MCM-41. Capillary condensation occurs through an irreversible discontinuous transition between the partially filled and the completely filled configurations, while evaporation occurs through the displacement at equilibrium of a hemispherical meniscus along the pore axis. Our data are also used to discuss the effect of surface chemistry and pore shape on the BET method. The BET surface for fully hydroxylated surfaces is much larger (by 10-20%) than the true geometrical surface. In contrast, the BET surface significantly underestimates the true surface when partially hydroxylated surfaces are considered. These results suggest that the surface chemistry and the choice of the system adsorbate/adsorbent is crucial in determining the surface area of solids using the BET method.
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Affiliation(s)
- Benoit Coasne
- Institut Charles Gerhardt Montpellier, CNRS (UMR 5253) and Université Montpellier 2, Montpellier, France.
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Feng Z, Zhang X, Wang W. Adsorption of fluids in a pore with chemical heterogeneities: the cooperative effect. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:051603. [PMID: 18643075 DOI: 10.1103/physreve.77.051603] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Indexed: 05/26/2023]
Abstract
In this work, we study the cooperative adsorption of fluids in a heterogeneous pore, in which the pore walls are composed of homogeneous substrates with chemical groups (CGs) decorating them. The adsorption caused by the homogeneous substrates alone and that by CGs do not add up to the overall adsorption, indicating the existence of a cooperative effect. The cooperative effect is the source of cooperative adsorption, and is characterized in this work by the ratio of the overall adsorption to the sum of adsorption by the substrate only and that by CGs. It is found that the cooperative adsorption does not depend monotonically on the substrate or the CGs. Two different origins of the cooperative adsorption play different roles depending on which one dominates the overall adsorption. Our simulations reveal that, when the homogeneous substrate dominates the overall adsorption, weakening of the attractive fluid-substrate interaction or alternatively strengthening of the fluid-CGs interaction leads to a stronger cooperative effect and enhances the cooperative adsorption. However, when CGs dominate the overall adsorption, weakening of the attractive fluid-CG interaction or strengthening the fluid-substrate interaction results in strong cooperative adsorption. In order to investigate the effects of the distribution of CGs on cooperative adsorption, a design-test method is generalized and used in this work. Simulation results show that the overall adsorption can be significantly affected by the CG distribution.
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Affiliation(s)
- Zhikuan Feng
- Division of Molecular and Materials Simulation, Key Laboratory for Nanomaterials, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, China
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Puibasset J, Pellenq RJM. Grand Canonical Monte Carlo Simulation Study of Water Adsorption in Silicalite at 300 K. J Phys Chem B 2008; 112:6390-7. [DOI: 10.1021/jp7097153] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Joël Puibasset
- Centre de Recherche sur la Matière Divisée, CNRS-Université d’Orléans, 1b, rue de la Ferollerie, 45071 Orléans cedex 02, France, and Centre de Recherche en Matière Condensée et Nanosciences, CNRS, Campus de Luminy, case 913, 13288 Marseille cedex 09, France
| | - Roland J.-M. Pellenq
- Centre de Recherche sur la Matière Divisée, CNRS-Université d’Orléans, 1b, rue de la Ferollerie, 45071 Orléans cedex 02, France, and Centre de Recherche en Matière Condensée et Nanosciences, CNRS, Campus de Luminy, case 913, 13288 Marseille cedex 09, France
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Coasne B, Galarneau A, Di Renzo F, Pellenq RJM. Molecular simulation of adsorption and intrusion in nanopores. ADSORPTION 2008. [DOI: 10.1007/s10450-008-9104-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Molecular simulation of the adsorption and structure of benzene confined in mesoporous silicas. ADSORPTION 2007. [DOI: 10.1007/s10450-007-9051-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Hung FR, Bhattacharya S, Coasne B, Thommes M, Gubbins KE. Argon and krypton adsorption on templated mesoporous silicas: molecular simulation and experiment. ADSORPTION 2007. [DOI: 10.1007/s10450-007-9034-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Modeling Triblock Surfactant Templated Mesoporous Silicas (MCF and SBA-15): A Mimetic Simulation Study. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s0167-2991(07)80068-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
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