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Diallo SO. Pore-size dependence and characteristics of water diffusion in slitlike micropores. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:012312. [PMID: 26274167 DOI: 10.1103/physreve.92.012312] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Indexed: 05/25/2023]
Abstract
The temperature dependence of the dynamics of water inside microporous activated carbon fibers (ACF) is investigated by means of incoherent elastic and quasielastic neutron-scattering techniques. The aim is to evaluate the effect of increasing pore size on the water dynamics in these primarily hydrophobic slit-shaped channels. Using two different micropore sizes (∼12 and 18 Å, denoted, respectively, ACF-10 and ACF-20), a clear suppression of the mobility of the water molecules is observed as the pore gap or temperature decreases. This suppression is accompanied by a systematic dependence of the average translational diffusion coefficient D(r) and relaxation time 〈τ(0)〉 of the restricted water on pore size and temperature. The observed D(r) values are tested against a proposed scaling law, in which the translational diffusion coefficient D(r) of water within a porous matrix was found to depend solely on two single parameters, a temperature-independent translational diffusion coefficient D(c) associated with the water bound to the pore walls and the ratio θ of this strictly confined water to the total water inside the pore, yielding unique characteristic parameters for water transport in these carbon channels across the investigated temperature range.
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Affiliation(s)
- S O Diallo
- Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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52
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Musso GE, Bottinelli E, Celi L, Magnacca G, Berlier G. Influence of surface functionalization on the hydrophilic character of mesoporous silica nanoparticles. Phys Chem Chem Phys 2015; 17:13882-94. [PMID: 25946487 DOI: 10.1039/c5cp00552c] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the synthesis and surface functionalization of MCM-41-like mesoporous silica nanoparticles (MSNs) with spheroidal shape and particle size of 141 ± 41 nm. The success of surface functionalization with aminopropyl and sodium ethylcarboxylate groups (giving amino-MSN and carboxy-MSN, respectively) was ascertained by infrared spectroscopy and ζ potential measurements. The former showed the decrease of surface silanol groups and the corresponding appearance of signals related to NH2 bending mode (δNH2) at 1595 cm(-1) and COO(-) stretching (νas and νsym) at 1562 and 1418 cm(-1). The latter showed a change in surface charge, in that the isoelectric point (IEP) changed from pH 3-4.5 to 8.5 when the MSN was functionalized with the amino groups, while carboxy-MSN showed a more negative charge in the whole pH range with respect to MSN. The hydrophilic character of the prepared materials was ascertained by quantitative microgravimetric measurements, allowing the calculation of the average isosteric adsorption heat (q[combining macron]st). This was found to be 51 ± 3 kJ mol(-1), 61 ± 4, and 65 ± 3 kJ mol(-1) for MSN, amino-MSN, and carboxy-MSN samples, respectively. The increase in q[combining macron]st after functionalization can be ascribed to the specific interaction of water molecules with the functionalizing agents, in agreement with a higher basicity with respect to silanol groups. Moreover, the possibility of multiple H-bonding interactions of water molecules with the carboxylate anion is put forward to account for the higher water uptake with respect to parent MSN.
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Affiliation(s)
- G E Musso
- Università di Torino, Dipartimento di Chimica and NIS Centre, Via P. Giuria 7, 10125 Torino, Italy.
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53
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Oschatz M, Leistner M, Nickel W, Kaskel S. Advanced structural analysis of nanoporous materials by thermal response measurements. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:4040-4047. [PMID: 25773383 DOI: 10.1021/acs.langmuir.5b00490] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Thermal response measurements based on optical adsorption calorimetry are presented as a versatile tool for the time-saving and profound characterization of the pore structure of porous carbon-based materials. This technique measures the time-resolved temperature change of an adsorbent during adsorption of a test gas. Six carbide and carbon materials with well-defined nanopore architecture including micro- and/or mesopores are characterized by thermal response measurements based on n-butane and carbon dioxide as the test gases. With this tool, the pore systems of the model materials can be clearly distinguished and accurately analyzed. The obtained calorimetric data are correlated with the adsorption/desorption isotherms of the materials. The pore structures can be estimated from a single experiment due to different adsorption enthalpies/temperature increases in micro- and mesopores. Adsorption/desorption cycling of n-butane at 298 K/1 bar with increasing desorption time allows to determine the pore structure of the materials in more detail due to different equilibration times. Adsorption of the organic test gas at selected relative pressures reveals specific contributions of particular pore systems to the increase of the temperature of the samples and different adsorption mechanisms. The use of carbon dioxide as the test gas at 298 K/1 bar provides detailed insights into the ultramicropore structure of the materials because under these conditions the adsorption of this test gas is very sensitive to the presence of pores smaller than 0.7 nm.
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Affiliation(s)
- Martin Oschatz
- †Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, D-01062 Dresden, Germany
| | - Matthias Leistner
- ‡Fraunhofer Institute for Material and Beam Technology (IWS), Winterbergstrasse 28, D-01277 Dresden, Germany
| | - Winfried Nickel
- †Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, D-01062 Dresden, Germany
| | - Stefan Kaskel
- †Department of Inorganic Chemistry, Dresden University of Technology, Bergstrasse 66, D-01062 Dresden, Germany
- ‡Fraunhofer Institute for Material and Beam Technology (IWS), Winterbergstrasse 28, D-01277 Dresden, Germany
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54
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Hao GP, Mondin G, Zheng Z, Biemelt T, Klosz S, Schubel R, Eychmüller A, Kaskel S. Unusual Ultra-Hydrophilic, Porous Carbon Cuboids for Atmospheric-Water Capture. Angew Chem Int Ed Engl 2014; 54:1941-5. [DOI: 10.1002/anie.201409439] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 11/03/2014] [Indexed: 11/09/2022]
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55
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Hao GP, Mondin G, Zheng Z, Biemelt T, Klosz S, Schubel R, Eychmüller A, Kaskel S. Ultrahydrophile poröse Kohlenstoffmaterialien mit quaderförmiger Morphologie und hoher Wasseraufnahmekapazität. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201409439] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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56
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Chen Q, Liu DP, Zhu JH, Han BH. Mesoporous Conjugated Polycarbazole with High Porosity via Structure Tuning. Macromolecules 2014. [DOI: 10.1021/ma501330v] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Qi Chen
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - De-Peng Liu
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - Jian-Hua Zhu
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - Bao-Hang Han
- National Center for Nanoscience and Technology, Beijing 100190, China
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57
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Roshchina TM, Shonija NK, Bernardoni F, Fadeev AY. Combined nitrogen, hexane, and benzene adsorption characterization of pores and surfaces of lyophobic mesoporous silicas. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:9355-9360. [PMID: 25040549 DOI: 10.1021/la500660s] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
For lyophobic porous surfaces, structural analysis by vapor adsorption is complicated due to weak adsorbate-adsorbent interactions and limited wetting of the pores (nonzero contact angles). To investigate further, adsorption isotherms of three distinct adsorbates (nitrogen - 77 K, n-hexane and benzene - 298 K) were studied for SBA-15 ordered mesoporous silica where the surface was functionalized with lyophobic perfluoroalkyl groups (C6F13 termini). The results demonstrated a clear advantage of the combined use of the adsorption isotherms of less surface sensitive (nitrogen) and more surface sensitive (hydrocarbons) adsorbates. The adsorption of nitrogen provided basic structural characteristics like surface area, pore volume, and pore size distribution, while the isotherms of benzene and n-hexane were used to characterize wetting (contact angles) and surface energy of the C6F13 surfaces within the pores. For the first time, the statistical film thickness for nitrogen, benzene, and n-hexane are being reported for the adsorption on fluorinated surfaces, thereby providing critical data for the pore size and the contact angle determination of the lyophobic materials.
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Affiliation(s)
- T M Roshchina
- Department of Chemistry, M.V. Lomonosov Moscow State University , Moscow 119991, Russian Federation
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58
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Stein IY, Lachman N, Devoe ME, Wardle BL. Exohedral physisorption of ambient moisture scales non-monotonically with fiber proximity in aligned carbon nanotube arrays. ACS NANO 2014; 8:4591-4599. [PMID: 24684313 DOI: 10.1021/nn5002408] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Here we present a study on the presence of physisorbed water on the surface of aligned carbon nanotubes (CNTs) in ambient conditions, where the wet CNT array mass can be more than 200% larger than that of dry CNTs, and modeling indicates that a water layer >5 nm thick can be present on the outer CNT surface. The experimentally observed nonlinear and non-monotonic dependence of the mass of adsorbed water on the CNT packing (volume fraction) originates from two competing modes. Physisorbed water cannot be neglected in the design and fabrication of materials and devices using nanowires/nanofibers, especially CNTs, and further experimental and ab initio studies on the influence of defects on the surface energies of CNTs, and nanowires/nanofibers in general, are necessary to understand the underlying physics and chemistry that govern this system.
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Affiliation(s)
- Itai Y Stein
- Department of Mechanical Engineering, ‡Department of Aeronautics and Astronautics, and §Department of Materials Science and Engineering, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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59
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Furukawa H, Gándara F, Zhang YB, Jiang J, Queen WL, Hudson MR, Yaghi OM. Water Adsorption in Porous Metal–Organic Frameworks and Related Materials. J Am Chem Soc 2014; 136:4369-81. [DOI: 10.1021/ja500330a] [Citation(s) in RCA: 1536] [Impact Index Per Article: 153.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Hiroyasu Furukawa
- Department
of Chemistry, University of California - Berkeley, Materials Sciences Division, Lawrence
Berkeley National Laboratory, and Kavli Energy
NanoSciences Institute at Berkeley, Berkeley, California 94720, United States
| | - Felipe Gándara
- Department
of Chemistry, University of California - Berkeley, Materials Sciences Division, Lawrence
Berkeley National Laboratory, and Kavli Energy
NanoSciences Institute at Berkeley, Berkeley, California 94720, United States
| | - Yue-Biao Zhang
- Department
of Chemistry, University of California - Berkeley, Materials Sciences Division, Lawrence
Berkeley National Laboratory, and Kavli Energy
NanoSciences Institute at Berkeley, Berkeley, California 94720, United States
| | - Juncong Jiang
- Department
of Chemistry, University of California - Berkeley, Materials Sciences Division, Lawrence
Berkeley National Laboratory, and Kavli Energy
NanoSciences Institute at Berkeley, Berkeley, California 94720, United States
| | - Wendy L. Queen
- The
Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Matthew R. Hudson
- Center
for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20885, United States
| | - Omar M. Yaghi
- Department
of Chemistry, University of California - Berkeley, Materials Sciences Division, Lawrence
Berkeley National Laboratory, and Kavli Energy
NanoSciences Institute at Berkeley, Berkeley, California 94720, United States
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60
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Ghosh P, Colón YJ, Snurr RQ. Water adsorption in UiO-66: the importance of defects. Chem Commun (Camb) 2014; 50:11329-31. [DOI: 10.1039/c4cc04945d] [Citation(s) in RCA: 191] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Density distributions of water in an ideal UiO-66 unit cell (left) and a unit cell missing linkers (right).
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Affiliation(s)
- Pritha Ghosh
- Department of Chemical & Biological Engineering
- Northwestern University
- Evanston, USA
| | - Yamil J. Colón
- Department of Chemical & Biological Engineering
- Northwestern University
- Evanston, USA
| | - Randall Q. Snurr
- Department of Chemical & Biological Engineering
- Northwestern University
- Evanston, USA
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