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The proton NMR imaging (microscopy) technique is employed to study the process of drying of alumina and titania porous catalyst support pellets impregnated with various liquids. Despite the short spin-spin relaxation times usually exhibited by liquids that permeate porous solids, the possibility to monitor their evaporation in real time by detecting one-dimensional liquid concentration profiles along the diameter of a cylindrical sample is demonstrated. In the qualitative discussion of the results, it is shown that the experiment is sensitive to the fine details of the drying process, such as the efficiency of liquid transport and peculiar profile shape transformations in the course of drying. A simple experiment is proposed that yields an empirical relation between the detected profile intensity and the actual liquid content, which allows one to correct the detected profiles for the inevitable T 2 -weighting effects.

The application of the 1H NMR microimaging technique to the indirect mapping of the spatial distribution of hexachloroplatinate dianion within porous alumina pellets is reported. It is demonstrated that the nuclear spin−lattice relaxation times of liquids filling the pores of the pellet increase in the presence of the adsorbed hexachloroplatinate dianion. The microimaging results for the supported catalysts with two types of platinum distribution (egg-shell and egg-white) are shown to be consistent with the results obtained by the staining method and electron probe microanalysis. Finally, the microimaging technique is employed for a nondestructive visualization of the dynamics of the active component redistribution in the course of the supported catalyst preparation by competitive adsorption.

The 1 H NMR microimaging technique is applied to study water vapor sorption by the individual cylindrical silica gel and alumina pellets impregnated with hygroscopic salts. The two-dimensional images or the onedimensional profiles of the sorbed water distribution are detected sequentially to monitor the transport of water within the pellets in real time in the course of the sorption process. The results identify the propagation of the sorbed water front through the dry regions of the pellets as the rate-limiting stage of the sorption process. This propagation can be facilitated by employing the pellets with the eggshell distribution of the salt, but in such cases the salt redistributes readily in the course of the sorption process, as revealed by the relaxation weighted 1 H NMR microimaging experiments in which paramagnetic salts are used. The diffusion equation with water content dependent diffusivity is employed to model the one-dimensional radial profiles of water distribution within the pellet with appropriate correction for the relaxation weighting effects.

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