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Agudelo A. C. Marco J. F. Gancedo J. R. Pérez-Alcázar G. A. 《Hyperfine Interactions》2002,139(1-4):141-152
The corrosion reaction of four Fe–Mn–Al alloys exposed to a cycling, dry–humid, SO2 (0.001% by volume) polluted atmosphere was studied. ICEMS, XPS, AES-SAM and transmission Mössbauer spectroscopy at different temperatures were employed to characterize the corrosion products. The analytical results indicate that (i) ferrihydrite is the main component of the rust; (ii) there is an abundant presence of Mn2+ and SO3
2–/SO4
2– on the top of the corrosion layer, the concentration of SO4
2– increasing with the number of cycles; and (iii) the magnetic hyperfine pattern exhibited by the series of low-temperature spectra of the rust is quite different from that observed in the rust formed under similar corrosive environments on iron and weathering steel. This latter finding is correlated with a slow rate of transformation of the Fe3+ species formed at the early stages of corrosion into -FeOOH, the usual final product of this type of corrosion processes. The sulphate anions, abundant inside the electrolyte during the wet periods, could be incorporated to the ferrihydrite structure being responsible for the Mössbauer spectral pattern recorded from the corrosion products at low temperatures. 相似文献
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Federico Cozzi Italo Pellegrini Gianpiero Adami Edoardo Reisenhofer Massimo Bovenzi Pierluigi Barbieri 《Central European Journal of Chemistry》2009,7(3):395-401
Sulphur K-edge X-ray absorption near edge structure (XANES) spectroscopy was used to identify sulphur compounds in PM10 samples
collected simultaneously at two sites with different environmental situations in the province of Trieste (NE of Italy), during
summer and winter seasons respectively. The first site is an industrial site located near a steel mill plant and the second
is a coastal site. The sulphur speciation at the industrial site has shown the presence of the following sulphur compounds
in both seasons: organic compounds (thiophenes or Polycyclic Aromatic Sulphur Heterocycles — PAHs) and sulphates while in
the winter season sulphites were also present. In the coastal site organic compounds (thiophenes or PASHs) and sulphate were
found during winter season, moreover bisulphates were found during summer season. Relative percentages of the different sulphur
compounds have shown that sulphate is the most abundant form of sulphur in the industrial site samples during both seasons
and in the coastal site sample collected during the winter season (> 98%); in the coastal site sample collected during the
summer season the relative percentages of bisulphate and sulphate were around 40% and 60% respectively.
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Rhodamine‐B has been proposed as a simple and sensitive colorimetric reagent for the estimation of sulphur dioxide in air. The air sample containing sulphur dioxide is passed through the absorbing solution of aqueous potassium iodate and N‐chlorosuccinimide to liberate iodine. The liberated iodine bleaches the pinkish red coloured rhodamine‐B dye, which measured at 555 nm. Beer's law was obeyed in the range of 0.5–5.0 μg, of sulphite per 25 mL (0.02–0.2 ppm) equivalent to 0.4–4.0 μg of sulphur dioxide (0.016–0.16 ppm). The molar absorptivity and Sandell's sensitivity were found to be 4.56 × 105 l mol?1 cm?1 and 0.00017 μg cm?2, respectively. The method has been suitably modified and successfully applied to the determination of sulphites in water after liberation of sulphur dioxide in acidic medium. 相似文献
4.
J.?R.?Sharmila B.?N.?SivasankarEmail author 《Journal of Thermal Analysis and Calorimetry》2004,78(3):933-940
Some new hydrazinium lanthanide sulphite hydrates of the formula N2H5Ln(SO3)2(H2O)2 where Ln=La, Pr, Nd and Sm and N2H5Ce(SO3)2 have been prepared and characterized by chemical analyses, magnetic studies and electronic and infrared spectroscopy. Thermal degradation of these complexes has been investigated by simultaneous TG-DTA techniques. These complexes decompose in air after dehydration to give the respective lanthanide sulphate as the final residue. However, cerium complex gives a mixture of cerium sulphate and ceric oxide as the end products. Cerium and neodymium complexes have also been subjected to thermal degradation in nitrogen atmosphere and the dehydration of neodymium complex was observed at a higher temperature than in air. The anhydrous neodymium and cerium complexes decompose in one step to give the respective sulphate in nitrogen atmosphere. 相似文献
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