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Reichenauer G, Balzer C, Meinusch R, Smarsly BM. Determining Mechanical Moduli of Disordered Materials with Hierarchical Porosity on Different Structural Levels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:9631-9639. [PMID: 35900873 DOI: 10.1021/acs.langmuir.2c01139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The impact of synthesis parameters and structural properties, respectively, on mechanical properties of porous materials on different structural levels provides valuable information for designing materials for specific applications. Within this study, we apply two nonstandard approaches for determining the mechanical properties of the mesoporous backbone phase in a series of disordered SiO2-based monolithic materials possessing hierarchical meso-macroporosity, that is, deformation upon mercury porosimetry and in situ dilatometry during nitrogen adsorption analysis. By using ordered porous model materials, the latter method has been recently proven to provide reliable mechanical moduli. This concept was now applied to a SiO2 monolith developed for high-performance liquid chromatography exhibiting disordered hierarchical meso- and macroporosity, as well as a series of analogue phenyl-modified meso-macroporous SiO2 monoliths with up to 36.1 at% organic modification. The phenyl group was introduced by adding phenyltrimethoxysilane to the sol-gel mixture. The study aimed at investigating in detail the impact of the organic modification on the morphology of the porous solid and the resulting mechanical properties. The study shows that both Hg porosimetry and in situ dilatometry performed during N2 adsorption at 77 K provide similar and reasonable moduli of compression for the mesoporous backbone of the silica materials investigated. These data were compared with moduli of the macroscopic sample as determined from sound velocity measurements by describing the fully connected macroporous backbone with a foam model. The comparison reveals an otherwise overseen side effect of the organic modification of the silica framework: in contrast to the pure reference SiO2 meso-macroporous monoliths, the hybrid material is composed of a more particulate morphology on the mesoscale, that is, mesoporous particles and corresponding necks between them are formed, which results in significant softening of the porous solid on the macroscale.
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Affiliation(s)
- Gudrun Reichenauer
- Bavarian Center for Applied Energy Research (ZAE Bayern), Magdelene-Schoch-Strasse 3, Würzburg 97074, Germany
| | - Christian Balzer
- Bavarian Center for Applied Energy Research (ZAE Bayern), Magdelene-Schoch-Strasse 3, Würzburg 97074, Germany
| | - Rafael Meinusch
- Institute of Physical Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, Giessen D-35392, Germany
| | - Bernd M Smarsly
- Institute of Physical Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, Giessen D-35392, Germany
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2
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Hara T, Baron GV, Hata K, Izumi Y, Bamba T, Desmet G. Performance of functionalized monolithic silica capillary columns with different mesopore sizes using radical polymerization of octadecyl methacrylate. J Chromatogr A 2021; 1651:462282. [PMID: 34144397 DOI: 10.1016/j.chroma.2021.462282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/26/2021] [Accepted: 05/18/2021] [Indexed: 11/29/2022]
Abstract
We report on the possibility to enhance the phase ratio and retention factor in silica monoliths. According to pioneering work done by Núñez et al. [1], this enhancement is pursued by applying a stationary phase layer via radical polymerization with octadecyl methacrylate (ODM) as an alternative to the customary octadecylsilylation (C18-derivatization). The difference in band broadening, retention factor and separation selectivity between both approaches was compared. Different hydrothermal treatment temperatures for the column preparation were applied to produce monolithic silica structures with three different mesopore sizes (resp. 10, 13, and 16 nm, as determined by argon physisorption) while maintaining similar domain size (sum of through-pore and skeleton size). It has been found that the columns with the poly(octadecyl methacrylate)-phase (ODM columns) provided a 60 to 80% higher retention factor in methanol-water mixture compared to the octadecylsilylated (ODS) columns produced by starting from similar silica backbone structures. In acetonitrile-water mixture, the enhancement is smaller (15 to 30% times higher), yet significant. By adjusting the fabrication conditions (for both the preparation of the monolithic backbones and the surface functionalization), the achieved retention factors (up k = 4.89 for pentylbenzene in 80:20% (v/v) methanol/water) are obviously higher than obtained in the pioneering study on ODM monoliths of Núñez et al. [1], and column clogging could be completely avoided. In addition, also separation efficiencies were significantly higher than shown in Ref. [1], with plate heights as low as 5.8 μm. These plate heights are however inferior to those observed on the ODS-modified sister columns. The difference can be explained by the slower intra-skeleton diffusion displayed by the ODM-modified columns, in turn caused by the larger obstruction to diffusion originating from the thicker stationary phase layer.
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Affiliation(s)
- Takeshi Hara
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; GL Sciences Inc., 237-2 Sayamagahara, Iruma, Saitama 358-0032, Japan
| | - Gino V Baron
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, Brussels B-1050, Belgium
| | - Kosuke Hata
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yoshihiro Izumi
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Takeshi Bamba
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
| | - Gert Desmet
- Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, Brussels B-1050, Belgium.
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3
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Immobilization of a copper complex based on the tripodal ligand (2‐aminoethyl)bis(2‐pyridylmethyl)amine (uns‐penp). Z Anorg Allg Chem 2021. [DOI: 10.1002/zaac.202100022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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4
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Kube SA, Turke K, Ellinghaus R, Wallacher D, Thommes M, Smarsly BM. Pore Size Gradient Effect in Monolithic Silica Mesopore Networks Revealed by In-Situ SAXS Physisorption. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:11996-12009. [PMID: 32936653 DOI: 10.1021/acs.langmuir.0c02183] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In disordered mesopore networks, the size distribution and connection between adjacent pores control desorption. How network characteristics can be extracted from corresponding physisorption isotherms is still a matter of research. To elucidate this, we study krypton physisorption (117.8 K) in the mesopore networks of "Nakanishi"-type monolithic silica. Combining physisorption in scanning acquisition mode with synchrotron-based in-situ SAXS provides complementary information on pore-filling states. These data reveal a mean pore size gradient in which pores grow smaller towards the material's network center. This structural motif cannot be derived through conventional isotherm analysis, but it is clearly exposed through scanning desorption curves which do not quite converge but merge individually with the main desorption isotherm before the lower hysteresis closing point. Hence, our findings provide the basis to build advanced models for analyzing scanning isotherms and extracting network characteristics through new descriptors, such as pore size and connectivity distributions as a function of the distance from the network center.
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Affiliation(s)
- Sebastian A Kube
- Department of Mechanical Engineering and Materials Science, Yale University, 15 Prospect Street, New Haven, Connecticut 06511, United States
| | | | | | - Dirk Wallacher
- Helmholtz Center Berlin for Materials and Energy, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Matthias Thommes
- Institute of Separation Science and Technology, Department of Chemical and Bioengineering, University of Erlangen-Nuremberg, Egerlandstrasse 3, 91058 Erlangen, Germany
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Hara T, Izumi Y, Hata K, V. Baron G, Bamba T, Desmet G. Performance of small-domain monolithic silica columns in nano-liquid chromatography and comparison with commercial packed bed columns with 2 µm particles. J Chromatogr A 2020; 1616:460804. [DOI: 10.1016/j.chroma.2019.460804] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 11/29/2019] [Accepted: 12/16/2019] [Indexed: 11/29/2022]
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6
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Futagami S, Hara T, Ottevaere H, Terryn H, Baron GV, Desmet G, De Malsche W. Chromatographic study of the structural properties of mesoporous silica layers deposited on radially elongated pillars. J Chromatogr A 2019; 1595:58-65. [DOI: 10.1016/j.chroma.2019.02.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 02/12/2019] [Accepted: 02/14/2019] [Indexed: 01/16/2023]
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7
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Beck G, Sieland M, Beleites JF, Marschall R, Smarsly BM. Independent Tailoring of Macropore and Mesopore Space in TiO 2 Monoliths. Inorg Chem 2019; 58:2599-2609. [PMID: 30681841 DOI: 10.1021/acs.inorgchem.8b03203] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
TiO2 monoliths were synthesized by a partially hindered sol-gel process. Various synthesis parameters like precursor concentrations and gelation temperature were varied to investigate changes in the macroporosity (being in the range of micrometers) and to determine influences on the macropore formation mechanism. Ionic liquids (ILs) were used as templates to vary the mesopore size independently from the macropore size. Depending on the synthesis parameters, TiO2 monoliths with exclusive mesoporosity or with hierarchical meso-/macropore structure were received, and the range of macropores can be shifted between 100 nm and 10 μm without influencing the mesopore diameter. Pore volumes up to 880 mm3/g were achieved, as determined by mercury intrusion porosimetry. The mesopores' diameter can be adjusted between 6 and 25 nm by adding different amounts of IL, and surface areas up to 260 m2/g and mesopore volumes of 0.5 cm3/g were obtained, based on N2-physisorption measurements. The monoliths were cladded by polymer, allowing for studying the flow-through properties depending on the macropore size. This precise control for tailored macropores enables the design of optimized TiO2 monoliths with respect to the desired application requirements.
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Affiliation(s)
- Giuliana Beck
- Institute of Physical Chemistry , Justus-Liebig University , Heinrich-Buff-Ring 17 , D-35392 Giessen , Germany
| | - Melanie Sieland
- Institute of Physical Chemistry , Justus-Liebig University , Heinrich-Buff-Ring 17 , D-35392 Giessen , Germany
| | - J Fabian Beleites
- Institute of Physical Chemistry , Justus-Liebig University , Heinrich-Buff-Ring 17 , D-35392 Giessen , Germany
| | - Roland Marschall
- Institute of Physical Chemistry , Justus-Liebig University , Heinrich-Buff-Ring 17 , D-35392 Giessen , Germany.,Physical Chemistry III , University of Bayreuth , D-95447 Bayreuth , Germany.,Center for Materials Research , Justus-Liebig University , Heinrich-Buff-Ring 16 , D-35392 Giessen , Germany
| | - Bernd M Smarsly
- Institute of Physical Chemistry , Justus-Liebig University , Heinrich-Buff-Ring 17 , D-35392 Giessen , Germany.,Center for Materials Research , Justus-Liebig University , Heinrich-Buff-Ring 16 , D-35392 Giessen , Germany
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8
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Hara T, Izumi Y, Nakao M, Hata K, Baron GV, Bamba T, Desmet G. Silica-based hybrid porous layers to enhance the retention and efficiency of open tubular capillary columns with a 5 μm inner diameter. J Chromatogr A 2018; 1580:63-71. [DOI: 10.1016/j.chroma.2018.10.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 10/09/2018] [Accepted: 10/14/2018] [Indexed: 12/16/2022]
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9
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Rodriguez ES, Lam SC, Haddad PR, Paull B. Reversed-Phase Functionalised Multi-lumen Capillary as Combined Concentrator, Separation Column, and ESI Emitter in Capillary-LC–MS. Chromatographia 2018. [DOI: 10.1007/s10337-018-3629-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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10
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Narciso Meirelles L, Silva Campos T, Rodriguez Z, Hernandez R, Svec F, Zajickova Z. “Single‐pot” approach towards the preparation of alkyl and polyfluoroalkyl organo‐silica monolithic capillaries for reversed‐phase liquid chromatography. J Sep Sci 2018; 41:3669-3676. [DOI: 10.1002/jssc.201800688] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 07/24/2018] [Accepted: 07/25/2018] [Indexed: 11/12/2022]
Affiliation(s)
| | | | - Zulema Rodriguez
- Department of Physical Sciences Barry University Miami Shores FL USA
| | - Rebecca Hernandez
- Department of Physical Sciences Barry University Miami Shores FL USA
| | - Frantisek Svec
- Department of Analytical Chemistry Faculty of Pharmacy Charles University Hradec Králové Czech Republic
| | - Zuzana Zajickova
- Department of Physical Sciences Barry University Miami Shores FL USA
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11
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Hara T, Futagami S, De Malsche W, Baron GV, Desmet G. Exploring the effect of mesopore size reduction on the column performance of silica-based open tubular capillary columns. J Chromatogr A 2018; 1552:87-91. [DOI: 10.1016/j.chroma.2018.03.050] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/26/2018] [Accepted: 03/27/2018] [Indexed: 11/17/2022]
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12
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Pires F, Otálora JAB, Bottoli CBG. New stationary phase for capillary liquid chromatography based on polydimethylsiloxane immobilized onto a Monolithic Silica Support. SEPARATION SCIENCE PLUS 2018. [DOI: 10.1002/sscp.201800033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Fabiane Pires
- Institute of Chemistry; University of Campinas - UNICAMP; Campinas SP Brazil
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13
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Hara T, Futagami S, De Malsche W, Eeltink S, Terryn H, Baron GV, Desmet G. Chromatographic Properties of Minimal Aspect Ratio Monolithic Silica Columns. Anal Chem 2017; 89:10948-10956. [DOI: 10.1021/acs.analchem.7b02764] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Takeshi Hara
- Vrije Universiteit Brussel, Department of Chemical
Engineering, Pleinlaan
2, B-1050 Brussels, Belgium
- Division
of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1
Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Shunta Futagami
- Vrije Universiteit Brussel, Department of Chemical
Engineering, Pleinlaan
2, B-1050 Brussels, Belgium
| | - Wim De Malsche
- Vrije Universiteit Brussel, Department of Chemical
Engineering, Pleinlaan
2, B-1050 Brussels, Belgium
| | - Sebastiaan Eeltink
- Vrije Universiteit Brussel, Department of Chemical
Engineering, Pleinlaan
2, B-1050 Brussels, Belgium
| | - Herman Terryn
- Vrije Universiteit Brussel, Department of Materials
and Chemistry, Pleinlaan
2, B-1050 Brussels, Belgium
| | - Gino V. Baron
- Vrije Universiteit Brussel, Department of Chemical
Engineering, Pleinlaan
2, B-1050 Brussels, Belgium
| | - Gert Desmet
- Vrije Universiteit Brussel, Department of Chemical
Engineering, Pleinlaan
2, B-1050 Brussels, Belgium
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14
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Advances in monolithic silica columns for high-performance liquid chromatography. J Anal Sci Technol 2017. [DOI: 10.1186/s40543-017-0125-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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15
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Meinusch R, Ellinghaus R, Hormann K, Tallarek U, Smarsly BM. On the underestimated impact of the gelation temperature on macro- and mesoporosity in monolithic silica. Phys Chem Chem Phys 2017; 19:14821-14834. [DOI: 10.1039/c7cp01846k] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Elucidating pore formation in monolithic SiO2: small variations in gelation temperature have a surprisingly strong impact on the meso- and macroporosity.
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Affiliation(s)
- Rafael Meinusch
- Institute of Physical Chemistry
- Justus-Liebig-Universität Giessen
- 35392 Giessen
- Germany
- Center for Materials Research (LaMa)
| | - Rüdiger Ellinghaus
- Institute of Physical Chemistry
- Justus-Liebig-Universität Giessen
- 35392 Giessen
- Germany
- Center for Materials Research (LaMa)
| | - Kristof Hormann
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
- Thermo Fisher Scientific
| | - Ulrich Tallarek
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
| | - Bernd M. Smarsly
- Institute of Physical Chemistry
- Justus-Liebig-Universität Giessen
- 35392 Giessen
- Germany
- Center for Materials Research (LaMa)
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16
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Zajickova Z. Advances in the development and applications of organic–silica hybrid monoliths. J Sep Sci 2016; 40:25-48. [DOI: 10.1002/jssc.201600774] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 08/11/2016] [Accepted: 09/04/2016] [Indexed: 12/12/2022]
Affiliation(s)
- Zuzana Zajickova
- Department of Physical Sciences Barry University Miami Shores FL USA
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17
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Ikegami T, Tanaka N. Recent Progress in Monolithic Silica Columns for High-Speed and High-Selectivity Separations. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2016; 9:317-342. [PMID: 27306311 DOI: 10.1146/annurev-anchem-071114-040102] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Monolithic silica columns have greater (through-pore size)/(skeleton size) ratios than particulate columns and fixed support structures in a column for chemical modification, resulting in high-efficiency columns and stationary phases. This review looks at how the size range of monolithic silica columns has been expanded, how high-efficiency monolithic silica columns have been realized, and how various methods of silica surface functionalization, leading to selective stationary phases, have been developed on monolithic silica supports, and provides information on the current status of these columns. Also discussed are the practical aspects of monolithic silica columns, including how their versatility can be improved by the preparation of small-sized structural features (sub-micron) and columns (1 mm ID or smaller) and by optimizing reaction conditions for in situ chemical modification with various restrictions, with an emphasis on recent research results for both topics.
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Affiliation(s)
- Tohru Ikegami
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Kyoto 606-8585, Japan;
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18
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Tanaka N. Introduction to “Monolithic columns in high-performance liquid chromatography” by G. Guiochon [J. Chromatogr. A 1168 (2007) 101–168]. J Chromatogr A 2016; 1446:15-6. [DOI: 10.1016/j.chroma.2015.10.084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 09/29/2015] [Accepted: 10/25/2015] [Indexed: 10/22/2022]
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19
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Reitz C, Breitung B, Schneider A, Wang D, von der Lehr M, Leichtweiss T, Janek J, Hahn H, Brezesinski T. Hierarchical Carbon with High Nitrogen Doping Level: A Versatile Anode and Cathode Host Material for Long-Life Lithium-Ion and Lithium-Sulfur Batteries. ACS APPLIED MATERIALS & INTERFACES 2016; 8:10274-82. [PMID: 26867115 DOI: 10.1021/acsami.5b12361] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Nitrogen-rich carbon with both a turbostratic microstructure and meso/macroporosity was prepared by hard templating through pyrolysis of a tricyanomethanide-based ionic liquid in the voids of a silica monolith template. This multifunctional carbon not only is a promising anode candidate for long-life lithium-ion batteries but also shows favorable properties as anode and cathode host material owing to a high nitrogen content (>8% after carbonization at 900 °C). To demonstrate the latter, the hierarchical carbon was melt-infiltrated with sulfur as well as coated by atomic layer deposition (ALD) of anatase TiO2, both of which led to high-quality nanocomposites. TiO2 ALD increased the specific capacity of the carbon while maintaining high Coulombic efficiency and cycle life: the composite exhibited stable performance in lithium half-cells, with excellent recovery of low rate capacities after thousands of cycles at 5C. Lithium-sulfur batteries using the sulfur/carbon composite also showed good cyclability, with reversible capacities of ∼700 mA·h·g(-1) at C/5 and without obvious decay over several hundred cycles. The present results demonstrate that nitrogen-rich carbon with an interconnected multimodal pore structure is very versatile and can be used as both active and inactive electrode material in high-performance lithium-based batteries.
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Affiliation(s)
| | | | | | | | - Martin von der Lehr
- Institute of Physical Chemistry, Justus Liebig University Giessen , Heinrich-Buff-Ring 17, 35392 Giessen, Germany
| | - Thomas Leichtweiss
- Institute of Physical Chemistry, Justus Liebig University Giessen , Heinrich-Buff-Ring 17, 35392 Giessen, Germany
| | - Jürgen Janek
- Institute of Physical Chemistry, Justus Liebig University Giessen , Heinrich-Buff-Ring 17, 35392 Giessen, Germany
| | - Horst Hahn
- Helmholtz Institute Ulm for Electrochemical Energy Storage , Helmholtzstrasse 11, 89081 Ulm, Germany
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20
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Hara T, Desmet G, Baron GV, Minakuchi H, Eeltink S. Effect of polyethylene glycol on pore structure and separation efficiency of silica-based monolithic capillary columns. J Chromatogr A 2016; 1442:42-52. [DOI: 10.1016/j.chroma.2016.03.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 10/22/2022]
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21
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von der Lehr M, Ellinghaus R, Smarsly BM. Hierarchically porous monolithic silica with varying porosity using bis(trimethoxysilyl)arenes as precursors. NEW J CHEM 2016. [DOI: 10.1039/c6nj00758a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Isomers of bis-(trimethoxysilyl)arenes were synthesized and used as organosilica precursors for the preparation of macro-mesoporous hybrid silica monoliths.
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Affiliation(s)
- Martin von der Lehr
- Institute of Physical Chemistry
- Justus Liebig University Giessen
- D-35392 Giessen
- Germany
| | - Rüdiger Ellinghaus
- Institute of Physical Chemistry
- Justus Liebig University Giessen
- D-35392 Giessen
- Germany
| | - Bernd M. Smarsly
- Institute of Physical Chemistry
- Justus Liebig University Giessen
- D-35392 Giessen
- Germany
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22
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Tanaka N, McCalley DV. Core–Shell, Ultrasmall Particles, Monoliths, and Other Support Materials in High-Performance Liquid Chromatography. Anal Chem 2015; 88:279-98. [DOI: 10.1021/acs.analchem.5b04093] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
| | - David V. McCalley
- Centre for Research in Biosciences, University of the West of England, Frenchay, Bristol BS16 1QY, U.K
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23
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Stoeckel D, Kübel C, Loeh MO, Smarsly BM, Tallarek U. Morphological Analysis of Physically Reconstructed Silica Monoliths with Submicrometer Macropores: Effect of Decreasing Domain Size on Structural Homogeneity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:7391-7400. [PMID: 25654337 DOI: 10.1021/la5046018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Silica monoliths are increasingly used as fixed-bed supports in separation and catalysis because their bimodal pore space architecture combines excellent mass transport properties with a large surface area. To optimize their performance, a quantitative relationship between morphology and transport characteristics has to be established, and synthesis conditions that lead to a desired morphology optimized for a targeted application must be identified. However, the effects of specific synthesis parameters on the structural properties of silica monoliths are still poorly understood. An important question is how far the macropore and domain size can be reduced without compromising the structural homogeneity. We address this question with quantitative morphological data derived for a set of eight macroporous-mesoporous silica monoliths with an average macropore size (d(macro)) of between 3.7 and 0.1 μm, prepared following an established route involving the sol-gel transition and phase separation. The macropore space of the silica monolith samples is reconstructed using focused ion beam scanning electron microscopy followed by a quantitative assessment of geometrical and topological properties based on chord length distributions (CLDs) and branch-node analysis of the pore network, respectively. We observe a significant increase in structural heterogeneity, indicated by a decrease in the parameter k derived from fitting a k-gamma function to the CLDs, when d(macro) reaches the submicrometer range. The compromised structural homogeneity of silica monoliths with submicrometer macropores could possibly originate from early structural freezing during the competitive processes of sol-gel transition and phase separation. It is therefore questionable if the common approach of reducing the morphological features of silica monoliths into the submicrometer regime by changing the point of sol-gel transition can be successful. Alternative strategies and a better understanding of the involved competitive processes should be the focus of future research.
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Affiliation(s)
- Daniela Stoeckel
- †Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
- ‡Institute of Physical Chemistry, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 58, 35392 Gießen, Germany
| | - Christian Kübel
- §Institute of Nanotechnology and Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Marc O Loeh
- ‡Institute of Physical Chemistry, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 58, 35392 Gießen, Germany
| | - Bernd M Smarsly
- ‡Institute of Physical Chemistry, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 58, 35392 Gießen, Germany
| | - Ulrich Tallarek
- †Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany
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Meinusch R, Hormann K, Hakim R, Tallarek U, Smarsly BM. Synthesis and morphological characterization of phenyl-modified macroporous–mesoporous hybrid silica monoliths. RSC Adv 2015. [DOI: 10.1039/c4ra16519e] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We present a comprehensive approach to characterize the one-pot synthesis, macropore space morphology, and chromatographic performance of phenyl-modified macro–mesoporous silica monoliths.
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Affiliation(s)
- Rafael Meinusch
- Institute of Physical Chemistry
- Justus-Liebig-Universität Giessen
- 35392 Giessen
- Germany
| | - Kristof Hormann
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
| | - Romana Hakim
- Institute of Physical Chemistry
- Justus-Liebig-Universität Giessen
- 35392 Giessen
- Germany
- Thermo Fisher Scientific
| | - Ulrich Tallarek
- Department of Chemistry
- Philipps-Universität Marburg
- 35032 Marburg
- Germany
| | - Bernd M. Smarsly
- Institute of Physical Chemistry
- Justus-Liebig-Universität Giessen
- 35392 Giessen
- Germany
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Stoeckel D, Kübel C, Hormann K, Höltzel A, Smarsly BM, Tallarek U. Morphological analysis of disordered macroporous-mesoporous solids based on physical reconstruction by nanoscale tomography. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:9022-9027. [PMID: 25036976 DOI: 10.1021/la502381m] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Solids with a hierarchically structured, disordered pore space, such as macroporous-mesoporous silica monoliths, are used as fixed beds in separation and catalysis. Targeted optimization of their functional properties requires a knowledge of the relation among their synthesis, morphology, and mass transport properties. However, an accurate and comprehensive morphological description has not been available for macroporous-mesoporous silica monoliths. Here we offer a solution to this problem based on the physical reconstruction of the hierarchically structured pore space by nanoscale tomography. Relying exclusively on image analysis, we deliver a concise, accurate, and model-free description of the void volume distribution and pore coordination inside the silica monolith. Structural features are connected to key transport properties (effective diffusion, hydrodynamic dispersion) of macropore and mesopore space. The presented approach is applicable to other fixed-bed formats of disordered macroporous-mesoporous solids, such as packings of mesoporous particles and organic-polymer monoliths.
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Affiliation(s)
- Daniela Stoeckel
- Department of Chemistry, Philipps-Universität Marburg , Hans-Meerwein-Strasse, 35032 Marburg, Germany
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von der Lehr M, Weidmann C, Mascotto S, Smarsly BM. Hierarchically Ordered Monolithic Silica with Bimodal Porosity Obtained by Hydrolysis and Condensation of 1,4-Bis(trimethoxysilyl)arenes. CHEM-ING-TECH 2013. [DOI: 10.1002/cite.201300079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Urban J, Jandera P. Recent advances in the design of organic polymer monoliths for reversed-phase and hydrophilic interaction chromatography separations of small molecules. Anal Bioanal Chem 2012; 405:2123-31. [PMID: 22995998 DOI: 10.1007/s00216-012-6392-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 08/24/2012] [Accepted: 08/27/2012] [Indexed: 10/27/2022]
Abstract
Owing to their favorable porous structure with pore size distribution shifted towards large flow-through pores, organic polymer monoliths have been mainly employed for the separation of macromolecules in gradient elution liquid chromatography. The absence of significant amounts of small pores with a stagnant mobile phase and the resulting low surface area were considered as the main reason for their poor behavior in the isocratic separation of small molecules. Several recent efforts have improved the separation power of organic polymer monoliths for small molecules offering column efficiency up to tens of thousands of plates per meter. These attempts include optimization of the composition of polymerization mixture, including the variation of functional monomer, the cross-linking monomer, and the porogen solvents mixture, adjustment of polymerization temperature, and time. Additionally, post-polymerization modifications including hypercross-linking and the use of carbon nanostructures showed significant improvement in the column properties. This review describes recent developments in the preparation of organic polymer monoliths suitable for the separation of small molecules in the isocratic mode as well as the main factors affecting the column efficiency.
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Affiliation(s)
- Jiri Urban
- Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic
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