Lead silicate solubility and the control of lead contamination in drinking water

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dc.contributor.authorWeaver, Cameron L.en
dc.contributor.departmentGeologyen
dc.date.accessioned2014-03-14T21:40:16Zen
dc.date.adate2009-07-11en
dc.date.available2014-03-14T21:40:16Zen
dc.date.issued1994en
dc.date.rdate2009-07-11en
dc.date.sdate2009-07-11en
dc.description.abstractThe intake of lead into the human body has become an area of major concern because high levels of lead are harmful and can cause physiological damage, especially in children. It has been suggested that adding NaSiO₃might control Pb²⁺ contamination of drinking water supplies (c.g., Thresh 1922). PbSiO₃ (am), the white, gelatinous precipitate formed by mixing Na₂SiO₃ solutions with Pb²⁺ bearing solutions, dissolves at pH<7 by the reaction: PbSiO₃ + H₂O + 2H⁺ = Pb²⁺ + H₄SiO₄ Measurements of the solubility of PbSiO₃ show that the K<sub>eq</sub> for this reaction is 7.41x10⁵ and the ΔG<sub>f</sub>° (PbSiO₃ (am)) is 1061.81 kJ mol⁻¹. This high value of K means that extreme amounts of a Na₂SiO₃ additive are required in a water supply system to reduce the Pb²⁺ concentration to the EPA MCL action level of 15 ppb. Furthermore, the high pH values that result from NaSiO₃ water treatments lead to the formation of lead hydroxycarbonate (hydrocerussite) because this carbonate phase is more stable in the pH range of natural waters (pH 5-8) than lead silicate.en
dc.description.degreeMaster of Scienceen
dc.format.extentvi, 31 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-07112009-040433en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-07112009-040433/en
dc.identifier.urihttp://hdl.handle.net/10919/43683en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1994.W395.pdfen
dc.relation.isformatofOCLC# 32451977en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V855 1994.W395en
dc.subject.lcshDrinking water -- Lead contenten
dc.subject.lcshLead silicates -- Solubilityen
dc.titleLead silicate solubility and the control of lead contamination in drinking wateren
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineGeologyen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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