Visualization of gas flow and diffusion in porous media.
The transport of gases in porous materials is a crucial component of many important processes in science and technology. In the present work, we demonstrate how magnetic resonance microscopy with continuous flow laser-polarized noble gases makes it possible to "light up" and thereby visualize, with unprecedented sensitivity and resolution, the dynamics of gases in samples of silica aerogels and zeolite molecular sieve particles. The "polarization-weighted" images of gas transport in aerogel fragments are correlated to the diffusion coefficient of xenon obtained from NMR pulsed-field gradient experiments. The technique provides a unique means of studying the combined effects of flow and diffusion in systems with macroscopic dimensions and microscopic internal pore structure.
Kaiser
L G
LG
Materials Sciences Division, Lawrence Berkeley National Laboratory, and Department of Chemistry, University of California, Berkeley, CA 94720, USA. lana@dirac.cchem.berkeley.edu
Meersmann
T
T
Logan
J W
JW
Pines
A
A
D004058:Diffusion; D009682:Magnetic Resonance Spectroscopy; D008853:Microscopy; D005741:Noble Gases; D016062:Porosity; D011312:Pressure; D012212:Rheology; D012822:Silicon Dioxide; D013997:Time Factors; D014978:Xenon; D014979:Xenon Isotopes
D005741:Noble Gases; D014979:Xenon Isotopes; D014978:Xenon; D012822:Silicon Dioxide