PFG NMR-STUDY OF MULTICOMPONENT SELF-DIFFUSION ON ACTIVE CARBONS

Using alternately H-1 and F-19 NMR, the pulsed field gradient (PFG) me thod of NMR spectroscopy is applied to study the self-diffusion of wat er and perfluorobenzene in active carbons of varying pore sizes. The m olecular mobilities are found to decrease with decreasing pore widths, exhibiting different patterns of concentration dependence. With respe ct to single-component adsorption, at comparable total sorbate concent ration in the mixture the diffusivity of either of the two components is reduced. This experimental finding is attributed to water bridges f ormed between primary adsorption sites on opposite pore walls.