Mass transfer in a nanoscale material enhanced by an opposing flux.
Diffusion is known to be quantified by measuring the rate of molecular fluxes in the direction of falling concentration. In contrast with intuition, considering methanol diffusion in a novel type of nanoporous material (MOF ZIF-8), this rate has now been found to be enhanced rather than slowed down by an opposing flux of labeled molecules. In terms of the key quantities of random particle movement, this result means that the self-diffusivity exceeds the transport diffusivity. It is rationalized by considering the strong intermolecular interaction and the dominating role of intercage hopping in mass transfer in the systems under study.
Chmelik
Christian
C
Leipzig University, Faculty of Physics and Geosciences, Linnéstrasse 5, D-04103 Leipzig, Germany. chmelik@physik.uni-leipzig.de
Bux
Helge
H
Caro
Jürgen
J
Heinke
Lars
L
Hibbe
Florian
F
Titze
Tobias
T
Kärger
Jörg
J