Aqueous alpha-lipoic acid solutions for removal of arsenic and mercury from materials used for museum artifacts

Persistent Link:
http://hdl.handle.net/10150/195574
Title:
Aqueous alpha-lipoic acid solutions for removal of arsenic and mercury from materials used for museum artifacts
Author:
Cross, Peggi
Issue Date:
2007
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:
Recorded use of pesticides in the conservation of artifacts dates back to the 16th century. Museums today are faced with a tremendous task of identification and remediation of pesticides from artifacts in order to protect museum workers and the general public. In addition, artifacts are being repatriated by Native American tribes for use in cultural ceremonies which may subject the practitioner to health risks. Arsenic and mercury salts are among the pesticides that were used that are highly persistent and toxic. The primary challenge lies in removing these hazardous and persistent metals without damaging the materials or pigments on the objects.Concentrated aqueous alpha-lipoic acid solutions were developed for removing arsenic and mercury pesticides from materials commonly used in museum artifacts. The alpha-lipoic acid solutions were reduced using natural sunlight or laboratory ultraviolet lamps to enhance the binding of arsenic. The solubility of alpha-lipoic acid in various organic and inorganic solutions was determined and environmental parameters that impact the reduction and solubility, such as pH and temperature, were examined. The kinetics of the reaction of arsenic (III) with reduced lipoic acid was examined by varying the reduced lipoic acid, base and arsenic concentration as well as temperature and stirring conditions. The results indicated that the reaction occurs at a moderate rate primarily within 8 seconds in air. The reaction is chemically rate limited enhanced at higher temperatures and lower pH. Aerobic conditions significantly decreased the extent of the reaction with increased stirring rate. This impact was minimized by using a nitrogen environment or by limiting agitation during the reaction step.The methods developed were capable of removing up to 1000 µg/cm2 arsenic (of sodium arsenite) from simulated artifacts to levels near the lower detection limit of the X-ray Fluorescence Spectrometer (1 µg/cm2) without leaving detectable residues according to Attenuated Total-Reflection Fourier Transform Infrared Spectroscopy. Similar results were achieved in removing mercury (of mercuric chloride) from non-sulfur containing materials; however, the solutions and processes developed were not capable of removing mercury from sulfur-containing materials such as wool and feathers.
Type:
text; Electronic Dissertation
Keywords:
arsenic; mercury; lipoic acid
Degree Name:
DMA
Degree Level:
doctoral
Degree Program:
Materials Science & Engineering; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Riley, Mark; Odegaard, Nancy
Committee Chair:
Riley, Mark

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleAqueous alpha-lipoic acid solutions for removal of arsenic and mercury from materials used for museum artifactsen_US
dc.creatorCross, Peggien_US
dc.contributor.authorCross, Peggien_US
dc.date.issued2007en_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.abstractRecorded use of pesticides in the conservation of artifacts dates back to the 16th century. Museums today are faced with a tremendous task of identification and remediation of pesticides from artifacts in order to protect museum workers and the general public. In addition, artifacts are being repatriated by Native American tribes for use in cultural ceremonies which may subject the practitioner to health risks. Arsenic and mercury salts are among the pesticides that were used that are highly persistent and toxic. The primary challenge lies in removing these hazardous and persistent metals without damaging the materials or pigments on the objects.Concentrated aqueous alpha-lipoic acid solutions were developed for removing arsenic and mercury pesticides from materials commonly used in museum artifacts. The alpha-lipoic acid solutions were reduced using natural sunlight or laboratory ultraviolet lamps to enhance the binding of arsenic. The solubility of alpha-lipoic acid in various organic and inorganic solutions was determined and environmental parameters that impact the reduction and solubility, such as pH and temperature, were examined. The kinetics of the reaction of arsenic (III) with reduced lipoic acid was examined by varying the reduced lipoic acid, base and arsenic concentration as well as temperature and stirring conditions. The results indicated that the reaction occurs at a moderate rate primarily within 8 seconds in air. The reaction is chemically rate limited enhanced at higher temperatures and lower pH. Aerobic conditions significantly decreased the extent of the reaction with increased stirring rate. This impact was minimized by using a nitrogen environment or by limiting agitation during the reaction step.The methods developed were capable of removing up to 1000 µg/cm2 arsenic (of sodium arsenite) from simulated artifacts to levels near the lower detection limit of the X-ray Fluorescence Spectrometer (1 µg/cm2) without leaving detectable residues according to Attenuated Total-Reflection Fourier Transform Infrared Spectroscopy. Similar results were achieved in removing mercury (of mercuric chloride) from non-sulfur containing materials; however, the solutions and processes developed were not capable of removing mercury from sulfur-containing materials such as wool and feathers.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectarsenicen_US
dc.subjectmercuryen_US
dc.subjectlipoic aciden_US
thesis.degree.nameDMAen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineMaterials Science & Engineeringen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorRiley, Marken_US
dc.contributor.advisorOdegaard, Nancyen_US
dc.contributor.chairRiley, Marken_US
dc.contributor.committeememberOdegaard, Nancyen_US
dc.contributor.committeememberLynch, Daviden_US
dc.contributor.committeememberEla, Wendellen_US
dc.identifier.proquest2052en_US
dc.identifier.oclc659747161en_US
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