Effects of surface chemistry on the porous structure of coal. Quarterly technical progress report, January 1996--March 1996

The primary objective of this work is to use {sup 129}Xe NMR to characterize the microporous structure of coals. Another objective is to use this technique to describe the effect of controlled opening of the micropores in a microporous carbon by oxygen chemisorption/desorption. The primary goal of the NMR work is to measure the micropore sizes in coal; more broadly, it is to better tailor the {sup 129}Xe NMR method for use with coal, and to investigate other ways it may be used to describe pore structure in coal, with emphasis on determining whether micropores in coal are connected or isolated. During this quarter, we have: (i) investigated particle size effect on the chemical shift of xenon adsorbed in a set of size-graded vitrinites; (ii) tracked the progress of xenon adsorption via xenon NMR, including particle size effect on the adsorption process; (iii) completed a preliminary test for chemical shift anisotropy in coal; and (iv) examined a microporous carbon by {sup 129}Xe NMR after two cycles of oxygen chemisorption/desorption