Speciation of Inorganic Mercury Compounds in Solid Samples via Thermo‐desorption Experiments

Abstract

To establish a standardized method for specifying mercury in solid samples, a database of relevant mercury species is created via thermo‐desorption. By measuring Hg(t) and Hg(0), different evaporation characteristics of mercury halides, sulfide, oxides, nitrates, and sulfates were recorded. It was possible to create a baseline for analyzing solid samples with unknown mercury content. All mercury species without a halide compound evaporate over 200 °C and as elemental mercury. All mercury halides evaporate mainly as oxidized species. From this fact it can be concluded that mercury halides desublimate when heated and have a vapor pressure as a solid. This unique characteristic was only seen by mercury halides. All other species seem to decompose into their single components when heated.

Adsorption of Mercury on Chlorine-Modified Activated Carbon: Breakthrough Curves and Temperature-Programmed Desorption

“…This new complex decomposes to HgCl 2 and Hg 0 during TPD. Klöfer et al . examined the gaseous products released during heating of solid HgCl 2 and solid Hg 2 Cl 2 .…”

“…This new complex decomposes to HgCl 2 and Hg 0 during TPD. Klofer et al 45 examined the gaseous products released during heating of solid HgCl 2 and solid Hg 2 Cl 2 . When solid HgCl 2 is heated, only HgCl 2 is present in the gas phase.…”

Preliminary exploration of direct mercury speciation in solid samples by using thermal release coupled to electrothermal atomic absorption spectrometry

“…It is known that mercury chloride sublimes below its boiling point of 276 °C. However, based on thermal release and TGA results as well as on published data, 14,19 we can assume that the formation of a signal with the maximum at 110 ± 8 °C can consider as corresponding to HgCl 2 sublimation. Thus, when using TR-ETA-AAS for mercury speciation in a mixture of mercury chloride, monomethylmercury chloride and mercury sulde, despite the fact that for some species transformation during continuous heating was conrmed, it does not prevent their baseline separation, as shown in Fig.…”

“…[9][10][11] Since then, a number of attempts have been made to upgrade and perfect this technique using various equipment and optimization schemes, as well as heating modes (stepwise and continuous). [12][13][14] However, the general problems concerning the essence of the process associated with the formation of an analytical signal have not yet been considered and understood. The most signicant of them is associated with the identication of mercury species in the sample when a number of compounds are simultaneously present in the mixture.…”