1
|
Liu T, Gautam S, Cole DR, Patankar S, Tomasko D, Zhou W, Rother G. Structure and dynamics of ethane confined in silica nanopores in the presence of CO 2. J Chem Phys 2020; 152:084707. [PMID: 32113366 PMCID: PMC7929619 DOI: 10.1063/1.5134451] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Fundamental understanding of the subcritical/supercritical behavior of key hydrocarbon species inside nano-porous matrices at elevated pressure and temperature is less developed compared to bulk fluids, but this knowledge is of great importance for chemical and energy engineering industries. This study explores in detail the structure and dynamics of ethane (C2H6) fluid confined in silica nanopores, with a focus on the effects of pressure and different ratios of C2H6 and CO2 at non-ambient temperature. Quasi-elastic neutron scattering (QENS) experiments were carried out for the pure C2H6, C2H6:CO2 = 3:1, and 1:3 mixed fluids confined in 4-nm cylindrical silica pores at three different pressures (30 bars, 65 bars, and 100 bars) at 323 K. Two Lorentzian functions were required to fit the spectra, corresponding to fast and slow translational motions. No localized motions (rotations and vibrations) were detected. Higher pressures resulted in hindrances of the diffusivity of C2H6 molecules in all systems investigated. Pore size was found to be an important factor, i.e., the dynamics of confined C2H6 is more restricted in smaller pores compared to the larger pores used in previous studies. Molecular dynamics simulations were performed to complement the QENS experiment at 65 bars, providing supportive structure information and comparable dynamic information. The simulations indicate that CO2 molecules are more strongly attracted to the pore surface compared to C2H6. The C2H6 molecules interacting with or near the pore surface form a dense first layer (L1) close to the pore surface and a second less dense layer (L2) extending into the pore center. Both the experiments and simulations revealed the role that CO2 molecules play in enhancing C2H6 diffusion ("molecular lubrication") at high CO2:C2H6 ratios. The energy scales of the two dynamic components, fast and slow, quantified by both techniques, are in very good agreement. Herein, the simulations identified the fast component as the main contributor to the dynamics. Molecule motions in the L2 region are mostly responsible for the dynamics (fast and slow) that can be detected by the instrument.
Collapse
Affiliation(s)
- Tingting Liu
- School of Earth Sciences, The Ohio State University, 125 South Oval Mall, Columbus, Ohio 43210, USA
| | - Siddharth Gautam
- School of Earth Sciences, The Ohio State University, 125 South Oval Mall, Columbus, Ohio 43210, USA
| | - David R. Cole
- School of Earth Sciences, The Ohio State University, 125 South Oval Mall, Columbus, Ohio 43210, USA
| | - Sumant Patankar
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 W Woodruff Ave., Columbus, Ohio 43210, USA
| | - David Tomasko
- William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 W Woodruff Ave., Columbus, Ohio 43210, USA
| | - Wei Zhou
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Gernot Rother
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| |
Collapse
|
2
|
Forman EM, Baniani A, Fan L, Ziegler KJ, Zhou E, Zhang F, Lively RP, Vasenkov S. Relationship between Ethane and Ethylene Diffusion inside ZIF-11 Crystals Confined in Polymers to Form Mixed-Matrix Membranes. J Memb Sci 2020; 593:117440. [PMID: 32863548 PMCID: PMC7449132 DOI: 10.1016/j.memsci.2019.117440] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Self-diffusivities of ethane were measured by multinuclear pulsed field gradient (PFG) NMR inside zeolitic imidazolate framework-11 (ZIF-11) crystals dispersed in several selected polymers to form mixed-matrix membranes (MMMs). These diffusivities were compared with the corresponding intracrystalline self-diffusivities in ZIF-11 crystal beds. It was observed that the confinement of ZIF-11 crystals in ZIF-11 / Torlon MMM can lead to a decrease in the ethane intracrystalline self-diffusivity. Such diffusivity decrease was observed at different temperatures used in this work. PFG NMR measurements of the temperature dependence of the intracrystalline self-diffusivity of ethylene in the same ZIF-11 / Torlon MMM revealed similar diffusivity decrease as well as an increase in the diffusion activation energy in comparison to those in unconfined ZIF-11 crystals in a crystal bed. These observations for ethane and ethylene were attributed to the reduction of the flexibility of the ZIF-11 framework due to the confinement in Torlon leading to a smaller effective aperture size of ZIF-11 crystals. Surprisingly, the intra-ZIF diffusion selectivity for ethane and ethylene was not changed appreciably by the confinement of ZIF-11 crystals in Torlon in comparison to the selectivity in a bed of ZIF-11 crystals. No ZIF-11 confinement effects leading to a reduction in the intracrystalline self-diffusivity of ethane and ethylene were observed for the other two studied MMM systems: ZIF-11 / Matrimid and ZIF-11 / 6FDA-DAM. The absence of the confinement effect in the latter MMMs can be related to the lower values of the polymer bulk modulus in these MMMs in comparison to that in ZIF-11 / Torlon MMM. In addition, there may be a contribution from possible differences in the ZIF-11/polymer adhesion in different MMM types.
Collapse
Affiliation(s)
- Evan M. Forman
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, USA
| | - Amineh Baniani
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, USA
| | - Lei Fan
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, USA
| | - Kirk J. Ziegler
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, USA
| | - Erkang Zhou
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Fengyi Zhang
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Ryan P. Lively
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Sergey Vasenkov
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, USA
| |
Collapse
|
3
|
Mehlhorn D, Valiullin R, Kärger J, Cho K, Ryoo R. Exploring Mass Transfer in Mesoporous Zeolites by NMR Diffusometry. MATERIALS (BASEL, SWITZERLAND) 2012; 5:699-720. [PMID: 28817004 PMCID: PMC5448955 DOI: 10.3390/ma5040699] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 04/02/2012] [Accepted: 04/15/2012] [Indexed: 11/16/2022]
Abstract
With the advent of mesoporous zeolites, the exploration of their transport properties has become a task of primary importance for the auspicious application of such materials in separation technology and heterogeneous catalysis. After reviewing the potential of the pulsed field gradient method of NMR (PFG NMR) for this purpose in general, in a case study using a specially prepared mesoporous zeolite NaCaA as a host system and propane as a guest molecule, examples of the attainable information are provided.
Collapse
Affiliation(s)
- Dirk Mehlhorn
- Faculty of Physics and Earth Science, University of Leipzig, Linnèstr. 5, Leipzig D-04103, Germany.
| | - Rustem Valiullin
- Faculty of Physics and Earth Science, University of Leipzig, Linnèstr. 5, Leipzig D-04103, Germany.
| | - Jörg Kärger
- Faculty of Physics and Earth Science, University of Leipzig, Linnèstr. 5, Leipzig D-04103, Germany.
| | - Kanghee Cho
- Department of Chemistry and Graduate School of Nanoscience and Technology (WCU), KAIST, Daejeon 305-701, Korea.
| | - Ryong Ryoo
- Department of Chemistry and Graduate School of Nanoscience and Technology (WCU), KAIST, Daejeon 305-701, Korea.
| |
Collapse
|
4
|
Valiullin R, Kärger J. The Impact of Mesopores on Mass Transfer in Nanoporous Materials: Evidence of Diffusion Measurement by NMR. CHEM-ING-TECH 2011. [DOI: 10.1002/cite.201000208] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
5
|
Chmelik C, Kärger J. In situ study on molecular diffusion phenomena in nanoporous catalytic solids. Chem Soc Rev 2010; 39:4864-84. [PMID: 20972502 DOI: 10.1039/c0cs00100g] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
As an omnipresent phenomenon in nature, diffusion is among the rate-determining processes in many technological processes. This is in particular true for catalytic conversion in nanoporous materials. We provide a critical review of the possibilities of exploring diffusion phenomena over microscopic dimensions in such media by direct experimental observation. By monitoring the probability distribution of molecular displacements as a function of time, the pulsed field gradient technique of NMR (PFG NMR) records the rate of molecular re-distribution. By varying the observation time, PFG NMR is thus able to trace even hierarchies of transport resistances as occurring, e.g., in catalyst particles in the form of binder-compacted assemblages of zeolite crystallites. Alternatively, and complementary to this information, interference microscopy (IFM) and IR microscopy (IRM) are able to follow the evolution of intracrystalline concentration profiles during uptake and release. This allows, in particular, an accurate quantification of the transport resistances on the surface of the individual crystallites and of the probability that reactant molecules from the gas phase, upon colliding with the external surface, are able to penetrate through such "surface barriers" into the crystal bulk phase. Being able to distinguish between different molecular species, IRM is able to record the evolution of intracrystalline concentration profiles even during multi-component adsorption and catalytic reactions (169 references).
Collapse
Affiliation(s)
- Christian Chmelik
- University of Leipzig, Faculty for Physics and Earth Sciences, Linnéstraße 5, D-04103 Leipzig, Germany.
| | | |
Collapse
|
6
|
Sanders M, Mueller R, Menjoge A, Vasenkov S. Pulsed Field Gradient Nuclear Magnetic Resonance Study of Time-Dependent Diffusion Behavior and Exchange of Lipids in Planar-Supported Lipid Bilayers. J Phys Chem B 2009; 113:14355-64. [DOI: 10.1021/jp9057093] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Monica Sanders
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611
| | - Robert Mueller
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611
| | - Amrish Menjoge
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611
| | - Sergey Vasenkov
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611
| |
Collapse
|
7
|
Kärger J, Caro J, Cool P, Coppens MO, Jones D, Kapteijn F, Rodríguez-Reinoso F, Stöcker M, Theodorou D, Vansant EF, Weitkamp J. Benefit of Microscopic Diffusion Measurement for the Characterization of Nanoporous Materials. Chem Eng Technol 2009. [DOI: 10.1002/ceat.200900160] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
8
|
Knauth M, Vasenkov S, Kärger J, Fritzsche S. Molecular dynamics study of sorbate diffusion in a simple porous membrane containing microporous nanocrystals and mesopores. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.07.106] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
9
|
Thompho S, Chanajaree R, Remsungnen T, Hannongbua S, Bopp PA, Fritzsche S. The Permeation of Methane Molecules through Silicalite-1 Surfaces. J Phys Chem A 2009; 113:2004-14. [DOI: 10.1021/jp808588n] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Somphob Thompho
- Institut für Theoretische Physik, Universität Leipzig, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand, Department of Mathematics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand, and Department of Chemistry, Université Bordeaux 1, Building A12, 351 Cours de la Libération, F-33405 Talence CEDEX, France
| | - Rungroj Chanajaree
- Institut für Theoretische Physik, Universität Leipzig, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand, Department of Mathematics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand, and Department of Chemistry, Université Bordeaux 1, Building A12, 351 Cours de la Libération, F-33405 Talence CEDEX, France
| | - Tawun Remsungnen
- Institut für Theoretische Physik, Universität Leipzig, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand, Department of Mathematics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand, and Department of Chemistry, Université Bordeaux 1, Building A12, 351 Cours de la Libération, F-33405 Talence CEDEX, France
| | - Supot Hannongbua
- Institut für Theoretische Physik, Universität Leipzig, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand, Department of Mathematics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand, and Department of Chemistry, Université Bordeaux 1, Building A12, 351 Cours de la Libération, F-33405 Talence CEDEX, France
| | - Philippe A. Bopp
- Institut für Theoretische Physik, Universität Leipzig, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand, Department of Mathematics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand, and Department of Chemistry, Université Bordeaux 1, Building A12, 351 Cours de la Libération, F-33405 Talence CEDEX, France
| | - Siegfried Fritzsche
- Institut für Theoretische Physik, Universität Leipzig, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand, Department of Mathematics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand, and Department of Chemistry, Université Bordeaux 1, Building A12, 351 Cours de la Libération, F-33405 Talence CEDEX, France
| |
Collapse
|
10
|
Valiullin R, Kärger J, Gläser R. Correlating phase behaviour and diffusion in mesopores: perspectives revealed by pulsed field gradient NMR. Phys Chem Chem Phys 2009; 11:2833-53. [DOI: 10.1039/b822939b] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
11
|
Krutyeva M, Kärger J. NMR diffusometry with beds of nanoporous host particles: an assessment of mass transfer in compartmented two-phase systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:10474-10479. [PMID: 18710267 DOI: 10.1021/la801426f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Molecular diffusion in a bed of zeolite crystallites is mimicked by dynamic Monte Carlo simulation of a particle hopping on a two-dimensional square lattice. The resulting probability distribution of molecular propagation (the "mean propagator") is used for a rigorous determination of the resulting dependencies of diffusion measurement by pulsed field gradient NMR. In the limiting cases of intracrystalline, restricted, and long-range diffusion, these dependencies are found to coincide with the well-known relations resulting from the application of a simplifying exchange model (the "two-region" approximation). The intensity of transport resistances on the boundary between the intra- and intercrystalline spaces, i.e., on the compartment boundaries, is only accessible in the intermediate case, i.e., for observation times comparable with the mean lifetimes within the different compartments. In this case, significant differences between the results of the rigorous treatment and the "two-region" approximation may occur.
Collapse
Affiliation(s)
- Margarita Krutyeva
- University of Leipzig, Department of Interface Physics, Linnéstrasse 5, Leipzig, Germany
| | | |
Collapse
|