Investigation of the porous structure of coal using ¹²⁹XE NMR with selective presaturation and saturation transfer

The technique of selective low power presaturation applied to ¹²⁹Xe NMR of xenon adsorbed in coal can clearly demonstrate the existence of a distribution of similar adsorption sites for xenon, where the signals from xenon in these sites are not resolved as individual signals. Differences in inter/extra particle exchange in two coals of different rank, available from a saturation transfer technique, are significant. This technique can be used to investigate pore connectivity in microporous materials of unknown pore structure.