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Internal Combustion Engines
Published in D. Yogi Goswami, Frank Kreith, Energy Conversion, 2017
David E. Klett, Elsayed M. Afify, Kalyan K. Srinivasan, Timothy J. Jacobs
Additives are also used to increase octane ratings. In the past, a common octane booster added to automotive fuels was lead alkyls—tetraethyl or tetramethyl lead. For environmental reasons, lead has been removed from automotive fuels in most countries. It is, however, still used in aviation fuel. Low-lead fuel has a concentration of about 0.5 g/L, which boosts octane rating by about five points. The use of leaded fuel in an engine equipped with a catalytic converter to reduce exhaust emissions will rapidly deactivate the catalyst (typically a noble metal such as platinum or rhodium), quickly destroying the utility of the catalytic converter. Octane-boosting additives in current use include the oxygenators methanol, ethanol, and methyl tertiary butyl ether (MTBE).
Petroleum Hydrocarbons
Published in G. Mattney Cole, Assessment and Remediation of Petroleum Contaminated Sites, 2018
In regular gasoline blends lead compounds, such as tetramethyllead and tetraethyllead, are used to increase the octane number. Other hazardous compounds, including ethylene dichloride, EDC, and ethylene dibromide, EDB, are added as lead scavengers to prevent buildup of lead oxide deposits. In the combustion chamber, EDC combines with lead to produce lead chloride, PbCl2, a volatile compound that is carried from the engine with the flow of exhaust gases.
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Published in Maurizio Cumo, Antonio Naviglio, Safety Design Criteria for Industrial Plants, 2019
Claudia Bartolomei, Sergio Paribelli
Toxicity — Tetramethyl lead is highly toxic if it is inhaled, if it comes in contact with the eyes, or if it is swallowed. It may be absorbed through skin, but in this case it is moderately toxic. Tetramethyl lead is suspected to be carcinogen. It affects the central nervous system; intoxication resembles that caused by tetraethyl lead.
Estimating the proportion of bioaccessible lead (BaPb) in household dust wipe samples: a comparison of IVBA and PBET methods
Published in Journal of Environmental Science and Health, Part A, 2023
Chandima Wekumbura, Ganga M. Hettiarachchi, Christina Sobin
Lead in household dust most commonly results from deteriorating lead-based paint, lead-contaminated soil that is tracked indoors, and somewhat less commonly, lead dust carried into the home on work clothes and skin from the adults’ occupational exposures.[6–8] Inhaled Pb is uniquely toxic because it is not believed to be directly influenced by biochemical processes that alter its absorption. In the gut however, ingested lead encounters stomach acids that usually alter its absorption. Thus, the toxicity of ingested lead is associated with its bioaccessibility, defined as the fraction of total lead available for absorption into the blood stream via the gut.[9–11] Dissolved Pb in the form of free ion (Pb2+) is the form that can enter the body and mimic and antagonize the action of calcium (Ca2+) and zinc (Zn2+) ions.[12,13] Ingested lead undergoes a dissolution process in the gastrointestinal tract and the dissolution process varies according to the chemical form of the Pb.[14,15] Materials containing PbCO3 (lead carbonate) or Pb-manganese (Pb–Mn) oxides as the dominant Pb species showed high bioaccessibility (ranging from 60% to 100%) in many in vivo and in vitro studies.[16–24] In addition, many studies reported the low solubility of Pb–phosphate and anglesite, galena, and some Fe–Pb, Pb–O, and Pb sulfate species.[10,25–28] Lead in soil can exist as Pb containing minerals or Pb-bound to other soil minerals. However, the overall solubility and bioaccessibility of soil Pb depend on the relative amounts and reactivity of the different chemical forms (such as crystallinity) and physical forms of Pb and Pb-bound minerals (e.g., accessibility). Most synthetic Pb-associated products contain highly bioaccessible Pb compounds, i.e., leaded paint: PbCrO4 (lead(II) chromate), Pb3O4 (lead(II, IV) oxide), and PbCO3 (lead(II) carbonate), leaded gasoline: Pb(C2H5)4 (tetraethyl and/or tetramethyl lead), and lead arsenate pesticide (PbHAsO4).