Speciation Of Sulfur Compounds Research Articles

Characterization of low molecular weight sulfur species in seaweed from the Antarctic continent.

Antarctic seaweeds are vital components of polar marine ecosystems, playing a crucial role in nutrient cycling and supporting diverse life forms. The sulfur content in these organisms is particularly interesting due to its implication in biogeochemical processes and potential impacts on local and global environmental systems. In this study, we present a comprehensive characterization of seaweed collected in the Antarctic in terms of their total sulfur content and its distribution among different classes of species, including thiols, using various methods and high-sensitivity techniques. The data presented in this paper are unprecedented in the scientific literature. These methods allowed for the determination of total sulfur content and the distribution of sulfur compounds in different fractions, such as water-soluble and proteins, as well as the speciation of sulfur compounds in these fractions, providing valuable insights into the chemical composition of these unique marine organisms. Our results revealed that the total sulfur concentration in Antarctic seaweeds varied widely across different species, ranging from 5.5 to 56gkg-1 dry weight. Furthermore, our investigation into the sulfur speciation revealed the presence of various sulfur compounds, including sulfate, and some thiols, which were quantified in all ten seaweed species evaluated. The concentration of these individual sulfur species also displayed considerable variability among the studied seaweeds. This study provides the first in-depth examination of total sulfur content and sulfur speciation in brown and red Antarctic seaweeds.

On the Possibility of Water Regeneration of Unimpregnated Activated Carbons Used as Hydrogen Sulfide Adsorbents

A bituminous coal and a coconut shell activated carbon were oxidized using nitric acid under conditions chosen to preserve their pore structures. The surface chemistry of the carbons was characterized using Boehm titration and thermal analysis. The carbons were then used as hydrogen sulfide adsorbents. The exhausted carbons were washed in order to remove the products of oxidation. The changes in the porous structure, surface pH, total sulfur content, and speciation of sulfur compounds were evaluated using sorption of nitrogen, thermal analysis, acid−base titrations, and ion chromatography. It was found that the presence of a trace amount of carbonates in coal-based carbon dramatically affects the mechanism of hydrogen sulfide immobilization. As a result of this, unreactive, insoluble, and bulky sulfur polymer which hinders the wash out of the deposits is formed. On the other hand, moderately oxidized samples, despite their lower H2S removal capacity, favor the formation of soluble sulfur oxides which are washed out as sulfuric acid. The H2S breakthrough capacity tests on regenerated samples revealed more than 30% recovery in their capability to effectively remove hydrogen sulfide.

Sulfur species in Rogoznica Lake

Reduced sulfur compounds were analyzed in the water column of a small sea lake, Rogoznica Lake, in dependence on the concentration of oxygen and organic matter, and temperature and salinity of the lake water. Cathodic stripping a.c. voltammetry was used to detect and quantify sulfur species. This is a direct method requiring no sample preparation. Rogoznica Lake was found rich with sulfur (up to 900 (μM), especially in the forms of sulfide and elemental sulfur. Anoxic water contained mainly sulfide (760 μM) while in the oxic layer only trace amounts of elemental sulfur were found (4–30 nM). Relatively high concentrations (140 μM) of elemental sulfur were found in the anoxic water too, which can be ascribed to the presence of polysulfide. It is known that due to biotic and abiotic processes the content and speciation of sulfur compounds in the samples change with time. Therefore, all samples were measured fresh, immediately after sampling. Additionally, we have investigated the influence of different preserving agents (formaldehyde, hydroxylamine and ascorbic acid) on electrochemical measurements and the concentration of sulfur. The best results were obtained with formaldehyde; the total concentration of sulfur was not changed in the sample within 7 days, while the ratio between elemental sulfur and sulfide was changed.

Speciation of sulfur compounds in individual aerosol particles

Speciation of sulfur compounds in individual aerosol particles