Redox Transformations and Sulfur Speciation in Flue Gas Desulferization Sludge

Persistent Link:
http://hdl.handle.net/10150/191187
Title:
Redox Transformations and Sulfur Speciation in Flue Gas Desulferization Sludge
Author:
Barlas, Sajid Ali,1961-
Issue Date:
1995
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Changes in redox potential (Eh), major sulfur species and the solubility of selenium and boron in reduced flue gas desulfurization (FGD) sludge, when exposed to atmosphere were studied in laboratory experiments. Also the effect of organic carbon and temperature on reduction of FGD sludge and changes in concentration of major S species was studied. Stable isotopic ratios of sulfur and carbon compounds were used to investigate the possible pathways of S transformation in FGD sludge disposal site. Oxidation of reduced sludge appears to be a two step process, a fast step of chemical oxidation followed by a slow step of biological oxidation and is significantly affected by moisture content and mixing of the sludge. With the addition of organic carbon Eh of the FGD sludge dropped exponentially and reduction of sulfate initiated at Eh of about -75 mV and was maximum in the range of -265 to -320 mV. Temperatur8e of the profile and organic carbon appear to be the key factors affecting the rate and extent of reduction in flooded FGD sludge. Selenium solubility decreased four times as Eh dropped from 215 mV to -350 mV while boron solubility was unchanged in this range of Eh. Stable isotopic ratio of sulfate and sulfide are typical of bacterial reduction and suggest that only aqueous sulfate was being reduced. The low δ³⁴S values of CaSO₄ from the upper layers of profile indicate the production and upward movement of hydrogen sulfide gas in the FGD sludge.
Type:
Dissertation-Reproduction (electronic); text
Keywords:
Hydrology.; Watershed management -- Arizona.; Flue gases -- Desulfurization.
Degree Name:
Ph. D.
Degree Level:
doctoral
Degree Program:
Department of Soil and Water Sciences; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Artiola, Janick F.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleRedox Transformations and Sulfur Speciation in Flue Gas Desulferization Sludgeen_US
dc.creatorBarlas, Sajid Ali,1961-en_US
dc.contributor.authorBarlas, Sajid Ali,1961-en_US
dc.date.issued1995en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractChanges in redox potential (Eh), major sulfur species and the solubility of selenium and boron in reduced flue gas desulfurization (FGD) sludge, when exposed to atmosphere were studied in laboratory experiments. Also the effect of organic carbon and temperature on reduction of FGD sludge and changes in concentration of major S species was studied. Stable isotopic ratios of sulfur and carbon compounds were used to investigate the possible pathways of S transformation in FGD sludge disposal site. Oxidation of reduced sludge appears to be a two step process, a fast step of chemical oxidation followed by a slow step of biological oxidation and is significantly affected by moisture content and mixing of the sludge. With the addition of organic carbon Eh of the FGD sludge dropped exponentially and reduction of sulfate initiated at Eh of about -75 mV and was maximum in the range of -265 to -320 mV. Temperatur8e of the profile and organic carbon appear to be the key factors affecting the rate and extent of reduction in flooded FGD sludge. Selenium solubility decreased four times as Eh dropped from 215 mV to -350 mV while boron solubility was unchanged in this range of Eh. Stable isotopic ratio of sulfate and sulfide are typical of bacterial reduction and suggest that only aqueous sulfate was being reduced. The low δ³⁴S values of CaSO₄ from the upper layers of profile indicate the production and upward movement of hydrogen sulfide gas in the FGD sludge.en_US
dc.description.notehydrology collectionen_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.typetexten_US
dc.subjectHydrology.en_US
dc.subjectWatershed management -- Arizona.en_US
dc.subjectFlue gases -- Desulfurization.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineDepartment of Soil and Water Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairArtiola, Janick F.en_US
dc.contributor.committeememberHendricks, David M.en_US
dc.contributor.committeememberBohn, Hinrich L.en_US
dc.contributor.committeememberFfolliott, Peter F.en_US
dc.identifier.oclc213443399en_US
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