[548] - Relaxation exchange in nanoporous silica by low-field NMR

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Paciok, E., 2012. Relaxation exchange in nanoporous silica by low-field NMR. PhD Report, Institute for Technical and Macromolecular Chemistry, RWTH Aachen, Aachen, Germany. Accessed from http://www.tr32db.uni-koeln.de/data.php?dataID=548 at 2019-04-25.
Title(s):Main Title: Relaxation exchange in nanoporous silica by low-field NMR
Description(s):Abstract: Investigating the 2D-T2-T2-relaxation exchange of interstitial water in a packing of sedimented Stöber-silicate spheres, we come the conclusion that contrary to its behaviour in macro-pores, water confined in nano-pores of silica exhibits enhanced diffusivity. The 2D-experiments, performed at different temperatures, reveal a temperaturedependent bimodal relaxation distribution and two-site relaxation exchange. Our recently introduced kinetic multisite exchange model is applied to derive the according exchange rates. The resulting Arrhenius plot produces an exchange activation energy of 7.1 kJ/mol, which is well below the hydrogen bond energy or the activation energy for self-diffusion of water in the bulk. A possible hoppingmechanism as the source of enhanced proton-diffusion in nanoporous silica is discussed, as well as its significance to mass transfer in porous media.
Responsible Party
Creator(s):Author: Eva Paciok
Publisher:CRC/TR32 Database (TR32DB)
TR32 Topic:Other
Subject(s):CRC/TR32 Keywords: NMR, PhD Report
File Details
File Name:Report1_Paciok_2012.pdf
Data Type:Text
File Size:3012 kB (2.941 MB)
Date(s):Available: 2012-01-01
Mime Type:application/pdf
Download Permission:OnlyTR32
General Access and Use Conditions:According to the TR32DB data policy agreement.
Access Limitations:According to the TR32DB data policy agreement.
Licence:TR32DB Data policy agreement
North:-no map data
Measurement Region:Laboratory
Measurement Location:--Laboratory--
Specific Informations - Report
Report Date:1st of January, 2012
Report Type:PhD Report
Report City:Aachen, Germany
Report Institution:Institute for Technical and Macromolecular Chemistry, RWTH Aachen
Number Of Pages:16
Period of Pages:1 - 16
Further Informations:TR32 Student Report Phase II
Metadata Details
Metadata Creator:Eva Paciok
Metadata Created:2013-10-31
Metadata Last Updated:2013-10-31
Funding Phase:2
Metadata Language:English
Metadata Version:V40
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