Aqueous solutions of sulfur produced via low-temperature hydrogen sulfide catalytic decomposition

Abstract

White globules of solid sulfur modification are obtained from saturated aqueous solutions. The chemical composition, morphology, and structure of the white sediment are investigated by means of X ray fluorescence analysis, scanning electron microscopy, and high resolution transmission electron microscopy. It is shown that the white sediment contains an unknown modification of globular hexagonal sulfur with glob ule sizes of 5-10 μm and interplanar distances of 0.45, 0.29, and 0.15 nm. A single absorption band at 880 cm -1 is found in the Raman scattering spectra of the saturated solutions above the sediment. It is sug gested that the white sediment consists of condensed S 2 phase.

The Reaction Mechanisms of H2S Decomposition into Hydrogen and Sulfur: Application of Classical and Biological Thermodynamics

“…As distinct from solid sulfur, the diatomic sulfur formed in the reaction (5) is well soluble in water, over 5 g of sulfur per liter of H 2 O [24]. The pH value and refractive index of the colorless sulfur solution are the same as those of the initial water, and the Raman spectrum of the solution exhibits only bands characteristic of water.…”

“…It is typical of solutions of diatomic gases that do not interact with water (N 2 , O 2 , H 2 , etc.). When the reaction (5) is carried out on metal catalyst immersed into water, white sulfur globules were obtained from the saturated solutions ( Figure 6) [24]. The size of the white spherical globules is up to 10 µm, while the smallest globules are practically transparent and colorless.…”

“…The size of the white spherical globules is up to 10 µm, while the smallest globules are practically transparent and colorless. The elemental analysis of the single globule obtained with the energy dispersive spectroscopy evidences in the only element -sulfur [24]. Electron diffraction on the separate sulfur globule indicates a hexagonal structure of the sulfur crystallites with the interplanar spacing of 0.45, 0.29, and 0.15 nm.…”

“…The scanning electron microscope images of white globular sulfur obtained from H 2 S on the metal catalyst immersed into water [20,24].…”

Purification of hydrogen sulfide from oxygen

“…One of the most complex and unpredictable problems encountered in the [1][2][3][4] was oxygen in the initial hydrogen sulfide as an uncontrolled impurity. The problem was that the reaction between hydrogen sulfide and oxygen is highly exothermic and proceeds spontaneously at room temperature in the presence of both sulfide and metal catalysts: 2 H 2 S + O 2 → 2 H 2 O + 1/4 S 8 (1) ( = -105.8 kcal/mol; = -55.3 cal/(mol К); = -89.3 kcal/mol; the data for our calculations were taken from [5]).…”