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In the Gutzeit test, AsH 3 is generated by reduction of aqueous arsenic compounds, typically arsenites, with Zn in the presence of H 2 SO 4. The evolved gaseous AsH 3 is then exposed to AgNO 3 either as powder or as a solution. With solid AgNO 3, AsH 3 reacts to produce yellow Ag 4 AsNO 3, whereas AsH 3 reacts with a solution of AgNO 3 to give ...
If, however, hydrogen is the desired end-product, the coal gas (primarily the CO product) undergoes the water gas shift reaction where more hydrogen is produced by additional reaction with water vapor: CO + H 2 O → CO 2 + H 2. Although other technologies for coal gasification currently exist, all employ, in general, the same chemical processes.
The hydrogen atoms in the arsinide anion may be substituted by organic or other groups which can then also produce ions, for example by methyl −CH 3, like in potassium methyl arsinide (K + CH 3 AsH −), [12] or by trimethylsilyl −Si(CH 3) 3. [1] The doubly bonded ligand =AsH (or AsH 2−) is called arsinidene. [11]
Steam can be added to the reaction in order to increase the generation of H 2, via the water-gas shift reaction (WGS) and/or steam methane reforming. The CLR process can produce a syngas with a H 2:CO molar ratio of 2:1 or higher, which is suitable for Fischer–Tropsch synthesis, methanol synthesis, or hydrogen production. The reduced oxygen ...
Synthesis gas ("syngas") is obtained from biomass/coal gasification is a mixture of hydrogen and carbon monoxide. The H 2:CO ratio is adjusted using the water-gas shift reaction. Coal-based FT plants produce varying amounts of CO 2, depending upon the energy source of the gasification process. However, most coal-based plants rely on the feed ...
Underground coal gasification converts coal to gas while still in the coal seam (in-situ). Gas is produced and extracted through wells drilled into the unmined coal seam. Injection wells are used to supply the oxidants (air, oxygen) and steam to ignite and fuel the underground combustion process. Separate production wells are used to bring the ...
Photomicrograph made with a scanning electron microscope and back-scatter detector: cross section of fly ash particles. Fly ash, flue ash, coal ash, or pulverised fuel ash (in the UK)—plurale tantum: coal combustion residuals (CCRs)—is a coal combustion product that is composed of the particulates that are driven out of coal-fired boilers together with the flue gases.
The presence of sulfur is another factor that affects the transformation of arsenic in natural water. Arsenic can precipitate when metal sulfides form. In this way, arsenic is removed from the water and its mobility decreases. When oxygen is present, bacteria oxidize reduced sulfur to generate energy, potentially releasing bound arsenic.