Hydrogen sulfide, adsorption and

Hydrogen Sulfide Adsorption and Decomposition on the Clean and S-Covered Ft(lll) Surface... 

Le Lauch, L.M., Subrenat, A., and Le Cloirec, P. (2003). Hydrogen sulfide adsorption and oxidation onto activated carbon cloth applications to odorous gaseous emission treatments. Langmuir, 19, 10869—77. 

Galea NM, Kadantsev ES, and Ziegler T. Studying reduction in solid oxide fuel cell activity with density functional theory-effects of hydrogen sulfide adsorption on nickel anode surface. JPhys Chem C 2007 111 14457-14468. 

The hydrogen sulfide adsorption on the HKUST-l/GO composites was only studied in moist conditions [44]. The choice was based on the presence of water in the ambient air and on the extensive studies of H2S reactive adsorption on carbonaceous materials where water was important for dissociation of hydrogen sulfide before its further reaction with surface active sites [5]. Here up to 20 wt% of H2S was adsorbed in the composite with the smallest content of GO. [44]. An increase in the GO content resulted in a decrease in the capacity but nevertheless it was higher than that on MOF... 

Petit C, Mendoza B, Bandosz TJ. Hydrogen sulfide adsorption on metal-organic frameworks and metal-organic frameworks / graphite oxide composites, ChemPhysChem 2010,11, 3678-3684. 

Bagreev, A. and Bandosz, T.J. (2002). A role of sodium hydroxide in the process of hydrogen sulfide adsorption/oxidation on caustic-impregnated activated carbons. Ind. Eng. Chem. Res., 41, 672—9. 

Tanada, S., Kita, T., Boki, K., and Kozaki, Y. (1985). Preparation of narrow pores carbon suitable for hydrogen sulfide adsorption. /. Environ. Sci. Health, A20, 87-96. 

Cal,. M.P., Strickler, B.W., and Lizzio, A.A. (2000). High temperature hydrogen sulfide adsorption on activated carbon. I. Effect of gas composition and metal addition. Carbon, 38, 1757-65. 

In all cases, a hydrogen sulfide adsorption-desorption unit will have to be included in the process following the pyrolysis step for gas purification and sulfur recovery for pulping. 

The analysis starts by ordering the components by composition, as given in Table 7.14. The first split suggested is the removal of the last three trace components hydrogen sulfide, benzene, and chloro-ethane. This split would correspond to the second heuristic in Table 7.12 remove troublesome trace impurities. The appropriate selector is of purification type. Four methods could be considered chemical absorption, catalytic conversion, molecular sieve adsorption and physical adsorption. 

Although direct relationship between the porosity of carbons and their hydrogen sulfide adsorption capacity was not established, the pore sizes should play a role in energetics of physical... 

The justification for the threshold in surface pH is based on the steps of hydrogen sulfide adsorption/oxidation on unmodified carbons [87, 94], They are as follows (1) H2S adsorption on the carbon surface, (2) its dissolution in a water film, (3) dissociation of H2S in an adsorbed state in the water film, (4) and surface reaction with adsorbed oxygen. 

Auger spectroscopy Auger electron spectroscopy is a powerful surface analysis technique, as the analytical signals come from the top few monolayer of the specimen. In this technique, a primary beam of electrons is used to produce inner shell vacancies in atoms of the specimen. This method has been used for the determination of sulfur, e.g., on GaAs surfaces and to study sulfur surface segregation in Ni-Al solid solutions and the adsorption on a GaAs (001) surface by hydrogen sulfide exposure and heat treatment. 

Okamoto, Y., Ohhara, M., Maezawa, A., Imanaka, T. Teranishi, S. Hydrogen sulfide adsorption on alumina, modified alumina, and molybdenum trioxide/alumina. J. Phys. Chem. 90, 2396-2407 (1986). 

Impurities such as chlorine, arsenic, and nickel used in the manufacturing process tend to shorten the life of the catalyst. The usual methods for desulfurization are by activated carbon adsorption at about 15 to 50°C or oxidation with zinc oxide or both. The use of zinc oxide is often preferred when large quantities of mercaptans and highly condensable hydrocarbons are present, which may quickly saturate the catalysts. The main function of the zinc oxide is to remove the hydrogen sulfide, mercaptans and chlorine. Combining activated carbon and zinc oxide is very effective in removing the different types of sulfide compounds. 

Figure 12-25. Equilibrium isotherms for hydrogen sulfide adsorption on molecular sieves, types 4A, 5A, and 13X. DataofUOP(1S93A)...

Sweetening. Another significant purification appHcation area for adsorption is sweetening. Hydrogen sulfide, mercaptans, organic sulfides and disulfides, and COS need to be removed to prevent corrosion and catalyst poisoning. They ate to be found in H2, natural gas, deethanizer overhead, and biogas. Often adsorption is attractive because it dries the stream as it sweetens. 

Adsorption systems employing molecular sieves are available for feed gases having low acid gas concentrations. Another option is based on the use of polymeric, semipermeable membranes which rely on the higher solubiHties and diffusion rates of carbon dioxide and hydrogen sulfide in the polymeric material relative to methane for membrane selectivity and separation of the various constituents. Membrane units have been designed that are effective at small and medium flow rates for the bulk removal of carbon dioxide. 

Adsorption Processes. The processes based on adsorption of hydrogen sulfide onto a fixed bed of soHd material are among the oldest types of gas treating appHcations (4). Two common sorbent materials for low concentration gas streams are iron oxide and zinc oxide. 

Molecular sieves are typically regenerated using a sHp stream of the treated gas at elevated temperature and reduced pressure. This regeneration step creates an enriched hydrogen sulfide stream which must then be further treated if the sulfur is to be recovered. A typical molecular sieve adsorption unit is shown schematically in Figure 2. 

Conversion Processes. Most of the adsorption and absorption processes remove hydrogen sulfide from sour gas streams thus producing both a sweetened product stream and an enriched hydrogen sulfide stream. In addition to the hydrogen sulfide, this latter stream can contain other co-absorbed species, potentially including carbon dioxide, hydrocarbons, and other sulfur compounds. Conversion processes treat the hydrogen sulfide stream to recover the sulfur as a salable product. 

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