For hydrogen sulfide poisoning

There is no proven antidote for hydrogen sulfide poisoning. Treatment consists of supportive measures such as evaluating and supporting airway, breathing, and circulation (ATSDR 1994). Sodium nitrite may or may not be an effective antidote, but if proper precautions in administration are observed, intravenous administration of sodium nitrite may help some hydrogen sulfide poisoned persons (Hall 1996 Hall and Rumack 1997). Hyperbaric oxygen therapy is controversial, but it may be effective for patients not treated successfully by other measures (ATSDR 1994). 

B. Nitrites are possibly effective for hydrogen sulfide poisoning if given within 30 minutes of exposure (see p 224). 

Shah, A.A. and F.C. Walsh. 2008. A model for hydrogen sulfide poisoning in proton exchange membrane fuel cells. /. Power Sources 185 287-301. 

After reading the sections provided in this part of the chapter, the reader should be able to formulate a numerical model that accounts for hydrogen sulfide poisoning of the anode of PEM fuel cells. 

The nervous system is vulnerable to attack from several directions. Neurons do not divide, and, therefore, death of a neuron always causes a permanent loss of a cell. The brain has a high demand for oxy gen. Lack of oxygen (hypoxia) rapidly causes brain damage. This manifests itself both on neurons and oligodendroglial cells. Anoxic brain damage may result from acute carbon monoxide, cyanide, and hydrogen sulfide poisonings. Carbon monoxide may also be formed in situ in the metabolism of dichloromethylene. 

In the case of life-threatening hydrogen sulfide poisoning, measurements of blood sulfide or urinary thiosulfate levels may be used to confirm exposure. However, samples need to be taken within two hours of exposure in order to be useful. The tests for measuring sulfide in the blood or thiosulfate in the urine are described in Section 2.7.1. 

Hall AH, Rumack BH. 1997. Hydrogen sulfide poisoning An antidotal role for sodium nitrite Vet Hum Toxicol39 152-154. 

Smilkstein MJ, Bronstein AC, Pickett HM, et al. 1985. Hyperbaric oxygen therapy for severe hydrogen sulfide poisoning. J Emerg Med 3 27-30. 

Nitrites have been used as vasodilators, as circulatory (blood pressure) depressants, as antidotes for cyanide and hydrogen sulfide poisoning (amyl and sodium nitrites), and to relieve smooth muscle... 

Poison titration is a convenient way to measure the concentration of active sites. The best procedure is to use a simple pulse reactor, such as that in Fig. 7.26. Pulses of a poisoning agent are injected between reactant pulses. If all the poison adsorbs irreversibly, then activity declines with each pulse. Typical results arc shown in Fig. 7.27, in which hydrogen sulfide poisons metal sites. Extrapolation of the activity curve to zero gives the amount of poison necessary to neutralize the active sites. A knowledge of surface stoichiometry is necessary to proceed further. For example, in Fig. 7.27 the assumed ratio was two nickel for each sulfur. This technique has the potential for innovative application to many systems. 

D. Enhanced elimination. There is no role for enhanced elimination procedures. Although hyperbaric oxygen therapy has been promoted for treatment of hydrogen sulfide poisoning, this is based on anecdotal cases and there is no convincing rationale or scientific evidence for its effectiveness. 

Continuing the line of catalytic oxidation on platinum. Peregrine Philips (1831, British Patent No. 6096) patented the oxidation of SO2 to SO3 on platinum, but he must have died before the first contact process plant for the production of sulfuric acid went on stream. And finally, along this line of work, Schweigger in the same year discovered that hydrogen sulfide poisoned platinum. 

Commercially, MCFCs are proposed by several vendors for biogas from anaerobic digestion processes of organic residues [37] and opportunity fuels such as landfill gas. These gases raise the issue of hydrogen sulfide poisoning, which is discussed in Section 3.2.2. 

The presence of sulfur compounds in the fuel stream of PEM fuel cells is due to the use of reformate as the fuel. The most common compound is hydrogen sulfide. Hydrogen sulfide poisoning of the catalyst sites is sometimes more severe than carbon monoxide poisoning and occurs even with trace amounts of sulfur. At low temperatures, the adsorption of sulfur onto the catalyst sites becomes very significant, thus, blocking the access for the hydrogen molecules to these sites. Heinzel et al. [Ill] reported a decrease... 

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. 

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