A convenient method for the quantitative determination of elemental sulfur in coal by HPLC analysis of perchloroethylene extracts

Abstract

A convenient method for the quantitative determination of elemental sulfur in coal is described. Elemental sulfur is extracted from the coal with hot perchloroethylene (PCE) (tetrachloroethene, C2CI4) and quantitatively determined by HPLC analysis on a Ci8 reverse-phase column using UV detection. Calibration solutions were prepared from sublimed sulfur. Results of quantitative HPLC analyses agreed with those of a chemical/spectroscopic analysis. The HPLC method was found to be linear over the concentration range of 6 X 10~1 234 to 2 X 10~2 6g/L. The lower detection limit was 4 X 1(H g/L, which for a coal sample of 20 g is equivalent to 0.0006% by weight of coal. Since elemental sulfur is known to react slowly with hydrocarbons at the temperature of boiling PCE, standard solutions of sulfur in PCE were heated with coals from the Argonne Premium Coal Sample program. Pseudo-first-order uptake of sulfur by the coals was observed over several weeks of heating. For the Illinois No. 6 premium coal, the rate constant for sulfur uptake was 9.7 X 10-7 s_1, too small for retrograde reactions between solubilized sulfur and coal to cause a significant loss in elemental sulfur isolated during the analytical extraction. No elemental sulfur was produced when the following pure compounds were heated to reflux in PCE for up to 1 week: benzyl sulfide, octyl sulfide, thiane, thiophene, benzothiophene, dibenzothiophene, sulfuric acid, or ferrous sulfate. A sluury of mineral pyrite in PCE contained elemental sulfur which increased in concentration with heating time.

Sulfur Speciation in Different Kerogens by XANES Spectroscopy

“…The peak positions of elemental sulfur and pyrite differ by only 0.5 eV, making it difficult to differentiate between the two. The earlier studies of high-sulfur kerogens did not report an examination of the possibility that there might be elemental sulfur in their samples. ,− Elemental sulfur is present in many coals and is thought to originate from pyrite oxidation . In kerogen, it could form by oxidation of pyrite or by either thermochemical reduction or biological reduction of sulfate .…”

Extraction and Quantitative Analysis of Elemental Sulfur from Sulfide Mineral Surfaces by High-Performance Liquid Chromatography

“…To make use of liquid chromatography for the analysis of elemental sulfur formed on sulfide mineral surfaces, an appropriate extraction method must be developed. Previously, extraction of elemental sulfur from coal using perchloroethylene maintained at reflux (120 °C) and subsequent analysis by high-performance liquid chromatography (HPLC) has been demonstrated (21). In the case of sulfide minerals, these rather harsh conditions may lead to further oxidation of the mineral and the generation of more elemental sulfur.…”

Analysis of elemental sulfur in sediments by reversed-phase high-performance liquid chromatography

“…The first time RP HPLC was used for analysis of elemental sulfur (SO) was in a study of the decomposition of sulfur-organic combinations in an aquatic environment [1]; later it was used to study soils and soil extracts [2,3], dormant and germinating s-spores of plants [4], and aqueous suspensions [5]. This method is also easily adapted for studies of S o in bottom sediments [6].…”