Showing papers by "Martin L. Gorbaty published in 1991"
TL;DR: Sulfur K edge X-ray adsorption near edge structure spectroscopy (XANES) was used for the direct determination and quantification of the forms of organically bound sulfur in nonvolatile petroleum and coal samples.
Abstract: Sulfur K edge X-ray adsorption near edge structure spectroscopy (XANES) and X-ray photoelectron spectroscopy (XPS) have been developed for the direct determination and quantification of the forms of organically bound sulfur in nonvolatile petroleum and coal samples. Both techniques were used to characterize organically bound sulfur forms in coals from the Argonne Premium Coal Sample Program. XANES and XPS spectra were taken of a number of model compounds, mixtures of model compounds, and coal samples. A third-derivative analysis of the XANES spectra involving curve reconstruction was required to account for the present of pyrite and aromatic sulfur. Curve resolution of the XPS spectra allowed approximate quantification of the surface aliphatic and aromatic components. XPS spectra showed little evidence of oxidized sulfur forms despite the presence of iron oxides and hydroxyoxides in the iron 2p spectra. Pyritic iron was identified only in Illinois No. 6 coal. The measured quantity of pyritic iron was used to interpret the sulfur 2p XPS spectrum. Both XANES and XPS show a monotonic increase of aromatic sulfur, defined as sulfur bound to two sp 2 -hybridized carbons, with increasing rank in the Argonne premium samples
170 citations
TL;DR: In this paper, a comparison of the TPD pattern of H2S evolution for high-rank coal with those of chars made from lower-rank coals at 400 and 750 °C shows that they are remarkably similar and suggests that the thermal reactions induced in sulphur species in laboratory pyrolysis experiments could be related to those that occur as a result of thermal reactions during coal metamorphism.
63 citations
TL;DR: In this paper, X-ray photoelectron spectroscopy (XPS) has been used in the study of the surface composition of iron and inorganic sulfur forms in coals from the Argonne Premium Sample Program.
Abstract: X-ray photoelectron spectroscopy (XPS) has been used in the study of the surface composition of iron and inorganic sulfur forms in coals from the Argonne Premium Sample Program. The concentration of iron at the coal surface can be very different than the bulk average. XPS and elemental analysis of selected particle size distributions show that the differences at the surface cannot be explained solely on the basis of particle size effects
20 citations
16 citations