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

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