FLOW AND TRANSPORT STUDIES IN (NON)CONSOLIDATED POROUS (BIO)SYSTEMS CONSISTING OF SOLID OR POROUS BEADS BY PFG NMR

Displacement imaging pulsed field gradient nuclear magnetic resonance (PFG NMR) is applied to a number of porous model systems, consisting o f either solid or porous particles, By pulsed field gradient nuclear m agnetic resonance, the molecular displacement can be measured that occ urs during a time interval, Delta, between two consecutive magnetic fi eld gradient pulses. In contrast to conventional techniques, which cov er displacements over distances several times the bead diameter, pulse d field gradient nuclear magnetic resonance covers displacements in th e order of subpore to several pore distances. Dimensionless scaling is possible based on the root-mean-square displacement normalised on the bead diameter. In solid particles, v and Delta are interchangeable, a lthough different flow regimens are covered. In porous particles, the exchange time between the stagnant mobile phase in the particles and t he flowing outside must be taken into account with respect to Delta as well as the porosity. (C) 1998 Elsevier Science Inc.