C. I. Wynter

57FE MOSSBAUER SPECTROSCOPIC INVESTIGATION OF LOW-IRON COALS AND THEIR FLYASH

Trends in the speciation of iron and sulfur in high iron/sulfur coals are well-established. Less is known concerning iron and sulfur speciation in low sulfur coals such as those investigated in this study. Low sulfur coals and their flyash from Thunder Bay, Ontario, Canada and Atikokan, West Virginia, U.S.A. have been investigated by means of 57Fe Mössbauer spectroscopy, X-ray diffraction and X-ray fluorescence. Virgin coals, containing approximately 0.1% Fe, exhibited Mössbauer spectra too low in intensity to characterize the phases present. The flyash exhibited well-resolved, simple doublets with ΔEQ=1.16 mm s−1 (Canada) and 1.26 mm s−1 (U.S.A.) and isomer shift values (w.r.t. Fe) of 0.22 mm s−1 and 0.23 mm s−1, respectively, characteristic of Fe3+. The linewidths of ∼0.80 mm s−1 are unusually large. Treatment of the flyash with cold, hydrofluoric acid resulted in a sample that exhibited very little absorption in its 57Fe Mössbauer spectrum. This result, in conjunction with the linewidths, indicates that the Fe is present in the flyash mainly as a silicate glass.

Paramagnetic Europium Salen Complex and Sickle‐Cell Anemia

A new europium salen complex, Eu(salen)2NH4, was synthesized, and its composition was confirmed by chemical analysis and infrared spectroscopy. Further characterization was carried out by 151 Eu Mossbauer spectroscopy and magnetic susceptibility measurements. Mossbauer spectroscopic measurements were made at varying temperatures between 9 K and room temperature and a value of Debye temperature of 133 ±5 K was computed. Both Mossbauer and magnetic susceptibility measurements confirmed the paramagnetic behavior of this complex and the trivalent state of the europium ion. In view of the fact that the “odd” paramagnetic molecule NO has been shown to reverse sickling of red blood cells in sickle cell anemia, the interaction between the paramagnetic europium salen complex and sickle cells was examined after incubation with this europium complex and shown to have similar effects.

57Fe Mössbauer Spectroscopy in Coal with Different Caloric Values

The environmental concern associated with mining and burning of coal has long been discussed in the literature. The present study deals with the four different ranks of coal with varying calorific values (CV) aiming to determine if these values are influenced by the sulfur content and/or the forms of iron-sulfur minerals associated with these types of coal. It has been established that Mossbauer spectroscopy is undoubtedly the best analytical tool for discerning iron minerals. The four different types of coal had CVs ranging from 32,403 to 16,000 kJ/kg and sulfur concentrations ranging from 0.25 to 2.5%. There was no direct correlation between the CV and the percentage of pyrites and ferrous sulphate. However, in general, as the CV increases, the percentage of sulfur increases.