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Wan Z, Zhou C, Lin Y, Chen L, Tian Z. Computational understanding of Na-LTA for ethanol-water separation. Phys Chem Chem Phys 2024; 26:4505-4510. [PMID: 38240530 DOI: 10.1039/d3cp06046b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
There is a growing demand for high purity ethanol as an electronic chemical. The conventional distillation process is effective for separating ethanol from water but consumes a significant amount of energy. Selective membrane separation using the LTA-type molecular sieve has been introduced as an alternative. The density functional theory simulation indicates that aluminum (Al) sites are evenly distributed throughout the framework, while sodium (Na+) ions are preferentially located in the six-membered ring. The movement of ethanol molecules can cause Na+ ions to be transported towards the eight-membered ring, hindering the passage of ethanol through the channel. In contrast, the energy barrier for water molecules passing through the channel occupied by Na+ ions is significantly lower, leading to a high level of selectivity for ethanol-water separation.
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Affiliation(s)
- Zicheng Wan
- School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, 313001, P. R. China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, P. R. China.
| | - Chen Zhou
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, P. R. China.
| | - Yichao Lin
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, P. R. China.
| | - Liang Chen
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, P. R. China.
| | - Ziqi Tian
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, P. R. China.
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Starke A, Pasel C, Bläker C, Eckardt T, Zimmermann J, Bathen D. Investigation of the Adsorption of Hydrogen Sulfide on Faujasite Zeolites Focusing on the Influence of Cations. ACS OMEGA 2022; 7:43665-43677. [PMID: 36506121 PMCID: PMC9730461 DOI: 10.1021/acsomega.2c04606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 10/25/2022] [Indexed: 06/17/2023]
Abstract
During the conversion of natural gas to liquified natural gas, sulfur components are separated by adsorption on zeolites. New zeolite materials may improve this adsorption process. In this paper, the adsorption of hydrogen sulfide is studied on seven faujasite (FAU) zeolites, which differ only in the number of sodium and calcium cations. From a pure NaX zeolite (13X), which contains only sodium cations, the calcium cation content was gradually increased by ion exchange. In a fixed-bed adsorber, cumulative equilibrium loadings of H2S on these zeolites were determined at concentrations between 50 and 2000 ppm at 25 and 85 °C and 1.3 bar (abs). Adsorption isotherms were analyzed considering the influence of cation positioning in the FAU zeolites. The experimental data indicate a superposition of a chemisorptive and a physisorptive mechanism. At a small number of chemisorptive sites, we conclude a dissociation of hydrogen sulfide and covalent bonding of the proton and the hydrogen sulfide ion to the zeolite lattice. The contribution of chemisorption exhibits a very low temperature dependence, which is typical for nearly irreversible reactions with an equilibrium strongly shifted to one side. With an increase in the proportion of Ca2+ cations, only physisorptive adsorption by electrostatic interaction with the cations in the lattice was observed. A large number of physisorptive sites have a lower energetic value. The share of physisorption strongly depends on temperature, which is characteristic of reversible equilibrium reactions.
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Affiliation(s)
- Annika Starke
- Chair of Thermal Process Engineering, University of Duisburg-Essen, Lotharstraße 1, D-47057Duisburg, Germany
| | - Christoph Pasel
- Chair of Thermal Process Engineering, University of Duisburg-Essen, Lotharstraße 1, D-47057Duisburg, Germany
| | - Christian Bläker
- Chair of Thermal Process Engineering, University of Duisburg-Essen, Lotharstraße 1, D-47057Duisburg, Germany
| | - Tobias Eckardt
- BASF Catalysts Germany GmbH, Große Drakeburger Straße 93-97, D-31582Nienburg, Germany
| | - Jens Zimmermann
- Chemiewerk Bad Köstritz GmbH, Heinrichshall 2, D-07586Bad Köstritz, Germany
| | - Dieter Bathen
- Chair of Thermal Process Engineering, University of Duisburg-Essen, Lotharstraße 1, D-47057Duisburg, Germany
- Institute of Energy and Environmental Technology, IUTA e. V., Bliersheimer Straße 60, D-47229Duisburg, Germany
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Abstract
AbstractNanoporous solids are ubiquitous in chemical, energy, and environmental processes, where controlled transport of molecules through the pores plays a crucial role. They are used as sorbents, chromatographic or membrane materials for separations, and as catalysts and catalyst supports. Defined as materials where confinement effects lead to substantial deviations from bulk diffusion, nanoporous materials include crystalline microporous zeotypes and metal–organic frameworks (MOFs), and a number of semi-crystalline and amorphous mesoporous solids, as well as hierarchically structured materials, containing both nanopores and wider meso- or macropores to facilitate transport over macroscopic distances. The ranges of pore sizes, shapes, and topologies spanned by these materials represent a considerable challenge for predicting molecular diffusivities, but fundamental understanding also provides an opportunity to guide the design of new nanoporous materials to increase the performance of transport limited processes. Remarkable progress in synthesis increasingly allows these designs to be put into practice. Molecular simulation techniques have been used in conjunction with experimental measurements to examine in detail the fundamental diffusion processes within nanoporous solids, to provide insight into the free energy landscape navigated by adsorbates, and to better understand nano-confinement effects. Pore network models, discrete particle models and synthesis-mimicking atomistic models allow to tackle diffusion in mesoporous and hierarchically structured porous materials, where multiscale approaches benefit from ever cheaper parallel computing and higher resolution imaging. Here, we discuss synergistic combinations of simulation and experiment to showcase theoretical progress and computational techniques that have been successful in predicting guest diffusion and providing insights. We also outline where new fundamental developments and experimental techniques are needed to enable more accurate predictions for complex systems.
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Rohling RY, Hensen EJM, Pidko EA. Multi-site Cooperativity in Alkali-Metal-Exchanged Faujasites for the Production of Biomass-Derived Aromatics. Chemphyschem 2018; 19:446-458. [PMID: 29105288 PMCID: PMC5820756 DOI: 10.1002/cphc.201701058] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/03/2017] [Indexed: 12/21/2022]
Abstract
The catalytic Diels-Alder cycloaddition-dehydration (DACD) reaction of furanics with ethylene is a promising route to bio-derived aromatics. The reaction can be catalyzed by alkali-metal-exchanged faujasites. Herein, the results of periodic DFT calculations based on accurate structural models of alkali-metal-exchanged zeolites are presented, revealing the fundamental roles that confinement and the nature of the exchangeable cations in zeolite micropores have in the performance of faujasite-based catalysts in the DACD reaction. Special attention is devoted to analyzing the effect of functional substituents on furanic substrates (furan, 2,5-dimethylfuran, 2,5-furandicarboxylic acid) on the catalyst behavior. It is demonstrated that the conventional reactivity theories of the Diels-Alder chemistry based on simplistic single-site Lewis acidity and substituent effects do not apply if catalytic processes in the multiple-site confined environment of zeolite nanopores are considered. The nature and cooperativity of the interactions between the multiple exchangeable cations and the substrates determine the reaction energetics of the elementary steps involved in the DACD process.
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Affiliation(s)
- Roderigh Y. Rohling
- Inorganic Materials Chemistry Group, Schuit Institute of CatalysisEindhoven University of Technology, P.O. Box 5135600MBEindhovenThe Netherlands
| | - Emiel J. M. Hensen
- Inorganic Materials Chemistry Group, Schuit Institute of CatalysisEindhoven University of Technology, P.O. Box 5135600MBEindhovenThe Netherlands
| | - Evgeny A. Pidko
- Inorganic Materials Chemistry Group, Schuit Institute of CatalysisEindhoven University of Technology, P.O. Box 5135600MBEindhovenThe Netherlands
- TheoMAT group, Laboratory of Solution Chemistry for Advanced Materials and TechnologiesITMO UniversityLomonosova 9St. Petersburg191002Russia
- Current Address: Inorganic Systems Engineering groupDepartment of Chemical EngineeringFaculty of Applied SciencesDelft University of TechnologyVan der Maasweg 92629HZDelftThe Netherlands
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O'Malley AJ, García Sakai V, Silverwood IP, Dimitratos N, Parker SF, Catlow CRA. Methanol diffusion in zeolite HY: a combined quasielastic neutron scattering and molecular dynamics simulation study. Phys Chem Chem Phys 2016; 18:17294-302. [DOI: 10.1039/c6cp01151a] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The diffusion of methanol in zeolite HY is studied using tandem quasielastic neutron scattering (QENS) experiments and molecular dynamics (MD) simulations at 300–400 K.
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Affiliation(s)
| | | | - Ian P. Silverwood
- ISIS Facility
- STFC Rutherford Appleton Laboratory
- Chilton
- Oxfordshire
- UK
| | | | - Stewart F. Parker
- The UK Catalysis Hub, Research Complex at Harwell
- Rutherford Appleton Laboratory
- Oxfordshire
- UK
- ISIS Facility
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Szymocha AM, Birczyński A, Lalowicz ZT, Stoch G, Krzystyniak M, Góra-Marek K. Water Confinement in Faujasite Cages: A Deuteron NMR Investigation in a Wide Temperature Range. 1. Low Temperature Spectra. J Phys Chem A 2014; 118:5359-70. [DOI: 10.1021/jp504648s] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
| | - A. Birczyński
- H. Niewodniczański Institute of Nuclear Physics PAS, ul. Radzikowskiego 152, 31-342 Kraków, Poland
| | - Z. T. Lalowicz
- H. Niewodniczański Institute of Nuclear Physics PAS, ul. Radzikowskiego 152, 31-342 Kraków, Poland
| | - G. Stoch
- H. Niewodniczański Institute of Nuclear Physics PAS, ul. Radzikowskiego 152, 31-342 Kraków, Poland
| | - M. Krzystyniak
- School
of Science and Technology, The Nottingham Trent University, Clifton
Lane, Nottingham NG11 8NS, U.K
- ISIS Spallation
Source, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K
| | - K. Góra-Marek
- Faculty
of Chemistry, Jagellonian University, 30-060 Kraków, Poland
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Joos L, Swisher JA, Smit B. Molecular simulation study of the competitive adsorption of H2O and CO2 in zeolite 13X. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:15936-15942. [PMID: 24313865 DOI: 10.1021/la403824g] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The presence of H2O in postcombustion gas streams is an important technical issue for deploying CO2-selective adsorbents. Because of its permanent dipole, H2O can interact strongly with materials where the selectivity for CO2 is a consequence of its quadrupole interacting with charges in the material. We performed molecular simulations to model the adsorption of pure H2O and CO2 as well as H2O/CO2 mixtures in 13X, a popular zeolite for CO2 capture processes that is commercially available. The simulations show that H2O reduces the capacity of these materials for adsorbing CO2 by an order of magnitude and that at the partial pressures of H2O relevant for postcombustion capture, 13X will be essentially saturated with H2O .
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Affiliation(s)
- Lennart Joos
- Department of Chemical and Biomolecular Engineering, University of California , Berkeley, California 94720, United States
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Lalowicz ZT, Stoch G, Birczyński A, Punkkinen M, Ylinen EE, Krzystyniak M, Góra-Marek K, Datka J. Translational and rotational mobility of methanol-d4 molecules in NaX and NaY zeolite cages: a deuteron NMR investigation. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2012; 45-46:66-74. [PMID: 22819978 DOI: 10.1016/j.ssnmr.2012.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 06/15/2012] [Accepted: 07/01/2012] [Indexed: 06/01/2023]
Abstract
Nuclear magnetic resonance (NMR) provides means to investigate molecular dynamics at every state of matter. Features characteristic for the gas phase, liquid-like layers and immobilized methanol-d(4) molecules in NaX and NaY zeolites were observed in the temperature range from 300 K down to 20K. The NMR spectra at low temperature are consistent with the model in which molecules are bonded at two positions: horizontal (methanol oxygen bonded to sodium cation) and vertical (hydrogen bonding of hydroxyl deuteron to zeolite framework oxygen). Narrow lines were observed at high temperature indicating an isotropic reorientation of a fraction of molecules. Deuteron spin-lattice relaxation gives evidence for the formation of trimers, based on observation of different relaxation rates for methyl and hydroxyl deuterons undergoing isotropic reorientation. Internal rotation of methyl groups and fixed positions of hydrogen bonded hydroxyl deuterons in methyl trimers provide relaxation rates observed experimentally. A change in the slope of the temperature dependence of both relaxation rates indicates a transition from the relaxation dominated by translational motion to prevailing contribution of reorientation. Trimers undergoing isotropic reorientation disintegrate and separate molecules become localized on adsorption centers at 166.7 K and 153.8K for NaX and NaY, respectively, as indicated by extreme broadening of deuteron NMR spectra. Molecules at vertical position remain localized up to high temperatures. That indicates the dominating role of the hydrogen bonding. Mobility of single molecules was observed for lower loading (86 molecules/uc) in NaX. A direct transition from translation to localization was observed at 190 K.
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Affiliation(s)
- Z T Lalowicz
- H. Niewodniczański Institute of Nuclear Physics of PAN, Kraków, Poland.
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Abstract
Zeolites are aluminosilicate solids bearing a negatively charged honeycomb framework of micropores into which molecules may be adsorbed for environmental decontamination, and to catalyse chemical reactions. They are central to green-chemistry since the necessity for organic solvents is minimised. Proton-exchanged (H) zeolites are extensively employed in the petrochemical industry for cracking crude oil fractions into fuels and chemical feedstocks for other industrial processes. Due to their ability to perform cation-exchange, in which the cations that are originally present to counterbalance the framework negative charge may be exchanged out of the zeolite by cations present in aqueous solution, zeolites are useful as industrial water-softeners, in the removal of radioactive Cs+ and Sr2+ cations from liquid nuclear waste and in the removal of toxic heavy metal cations from groundwaters and run-off waters. Surfactant-modified zeolites (SMZ) find particular application in the co-removal of both toxic anions and organic pollutants. Toxic anions such as arsenite, arsenate, chromate, cyanide and radioactive iodide can also be removed by adsorption into zeolites that have been previously loaded with co-precipitating metal cations such as Ag+ and Pb2+ which form practically insoluble complexes that are contained within the zeolite matrix.
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Smeekens S, Heylen S, Villani K, Houthoofd K, Godard E, Tromp M, Seo JW, DeMarco M, Kirschhock CEA, Martens JA. Reversible NOx storage over Ru/Na–Y zeolite. Chem Sci 2010. [DOI: 10.1039/c0sc00285b] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Plant DF, Maurin G, Bell RG. Diffusion of Methanol in Zeolite NaY: A Molecular Dynamics Study. J Phys Chem B 2007; 111:2836-44. [PMID: 17388427 DOI: 10.1021/jp0674524] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular dynamics simulations were performed in order to obtain a detailed understanding of the self-diffusion mechanisms of methanol in the zeolite NaY system. We derived a new force-field term to describe the interactions between the methanol molecules and the extraframework cations. From the simulations, we show that diffusive behavior in the high-temperature range consists of a combination of both short- and long-range motions at low and intermediate loadings. This type of motion is characterized by an activation energy that decreases as the loading increases. At low loadings, we also observe short-range diffusive behavior based on a surface-mediated mechanism. The short-range behavior corresponds to motion only on the length scale of an FAU supercage, whereas the long-range behavior involves intercage diffusion. For the saturation loading corresponding to 96 methanol molecules per unit cell, only short-range motions within the same supercage predominate. Finally, the preferential arrangement of the adsorbate molecules around the extraframework cations are examined and compared with those previously deduced from experimental data.
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Affiliation(s)
- David F Plant
- Davy Faraday Research Laboratory, Royal Institution of Great Britain, 21 Albemarle Street, London W1S 4BS, United Kingdom
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Molecular Modelling in Zeolite Science. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s0167-2991(07)80807-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2023]
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