Application of cyclodextrins for remediation of organic compounds and heavy metals in soils.

Persistent Link:
http://hdl.handle.net/10150/187213
Title:
Application of cyclodextrins for remediation of organic compounds and heavy metals in soils.
Author:
Wang, Xiaojiang
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:
Cyclodextrins, being microbially produced compounds, were investigated for their potential to increase the removal of low-polarity organic compounds in subsurface remediation. It is found that the apparent solubilities of many hydrophobic organic compounds are significantly increased in hydroxypropyl-β-cyclodextrin (HPCD) solutions. The relative solubilities (S(t)/S ₒ) of compounds increase linearly with increasing HPCD concentrations. The solubilization power of HPCD is found to be much greater than that of miscible cosolvents and to be less than that of synthetic surfactants. The lower solubilization power of cyclodextrin can be increased by the addition of a third component such as cyclopentanol. The addition of 0.1% cyclopentanol significantly enhances the solubilization power of β -cyclodextrin (β -CD) for pyrene, acenaphthene, phenanthrene, and fluoranthene which are able to form 1:2 complexes with β-CD in the presence of cyclopentanol. In contrast, cyclopentanol produces no pronounced effect and a marked decrease in the solubilization power of β -CD for naphthalene and anthracene, respectively. These two compounds form 1:1 complexes with β -CD both in the absence and presence of cyclopentanol. The solubilization of all PAHs by γ-cyclodextrin (γ -CD) is significantly enhanced by 1% cyclopentanol. This result indicates that cyclopentanol can increase the hydrophobicity of β -CD cavity without inducing structure-dependent selectivity. We investigated the ability of a modified cyclodextrin, carboxymethyl- β-cyclodextrin (CMCD), to simultaneously complex with low-polarity organic compounds and heavy metals. The results of this experiment show that CMCD could simultaneously enhance the solubilities of the selected organic compounds and complex with Cd²⁺. The complexation of Cd²⁺ by CMCD is not significantly affected by changes in pH or by the presence of relatively high concentration of Ca²⁺.
Type:
text; Dissertation-Reproduction (electronic)
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Soil and Water Science; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Brusseau, Mark L.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleApplication of cyclodextrins for remediation of organic compounds and heavy metals in soils.en_US
dc.creatorWang, Xiaojiangen_US
dc.contributor.authorWang, Xiaojiangen_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.abstractCyclodextrins, being microbially produced compounds, were investigated for their potential to increase the removal of low-polarity organic compounds in subsurface remediation. It is found that the apparent solubilities of many hydrophobic organic compounds are significantly increased in hydroxypropyl-β-cyclodextrin (HPCD) solutions. The relative solubilities (S(t)/S ₒ) of compounds increase linearly with increasing HPCD concentrations. The solubilization power of HPCD is found to be much greater than that of miscible cosolvents and to be less than that of synthetic surfactants. The lower solubilization power of cyclodextrin can be increased by the addition of a third component such as cyclopentanol. The addition of 0.1% cyclopentanol significantly enhances the solubilization power of β -cyclodextrin (β -CD) for pyrene, acenaphthene, phenanthrene, and fluoranthene which are able to form 1:2 complexes with β-CD in the presence of cyclopentanol. In contrast, cyclopentanol produces no pronounced effect and a marked decrease in the solubilization power of β -CD for naphthalene and anthracene, respectively. These two compounds form 1:1 complexes with β -CD both in the absence and presence of cyclopentanol. The solubilization of all PAHs by γ-cyclodextrin (γ -CD) is significantly enhanced by 1% cyclopentanol. This result indicates that cyclopentanol can increase the hydrophobicity of β -CD cavity without inducing structure-dependent selectivity. We investigated the ability of a modified cyclodextrin, carboxymethyl- β-cyclodextrin (CMCD), to simultaneously complex with low-polarity organic compounds and heavy metals. The results of this experiment show that CMCD could simultaneously enhance the solubilities of the selected organic compounds and complex with Cd²⁺. The complexation of Cd²⁺ by CMCD is not significantly affected by changes in pH or by the presence of relatively high concentration of Ca²⁺.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineSoil and Water Scienceen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairBrusseau, Mark L.en_US
dc.contributor.committeememberMiller, Raina M.en_US
dc.contributor.committeememberArtiola, Janick F.en_US
dc.identifier.proquest9603360en_US
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