Physico-chemical factors affecting rhamnolipid (biosurfactant) application for removal of metal contaminants from soil

Persistent Link:
http://hdl.handle.net/10150/282826
Title:
Physico-chemical factors affecting rhamnolipid (biosurfactant) application for removal of metal contaminants from soil
Author:
Ochoa Loza, Francisco Javier, 1956-
Issue Date:
1998
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:
Contamination of soil and groundwater environments by toxic metals and organic compounds is of major concern because of the potential health hazard posed for humans. Remediation of such sites may require the addition of chemical agents that help in the mobilization of contaminants which are likely to be bound to solid surfaces. Surfactants are one of the agents proposed for addition to enhance the removal of soil-bound contaminants. In this dissertation, a series of laboratory experiments were conducted to investigate constraints to the potential application of a microbially produced surfactant (biosurfactant) for removal of metal contaminants from soil. The first part of the dissertation describes the measurement of stability constants and 13 metals including ten of the metals most frequently found in contaminated sites as well as three of the most common metal cations found in soil, Ca²⁺, Mg ²⁺, and K⁺. The second part of the dissertation describes a series of experiments designed to determine the interaction of the biosurfactant with soil matrix components including clays, metal oxides, and organic matter. The biosurfactant used in this research was monorhamnolipid produced by Pseudomonas aeruginosa ATCC 9027. A mixture of mono- and dirhamnolipid produced by P. aeruginosa UG2 was also used in some cases. Results showed that selectivity of the monorhamnolipid followed the order: Al³⁺ > Cu²⁺ > Pb²⁺ > Cd²⁺ > Zn²⁺ > Fe³⁺ > Hg ²⁺ > Ca²⁺ > Co²⁺ > Ni²⁺ > Mn²⁺ > Mg²⁺ > K⁺. These results suggest that monorhamnolipid binds common metal contaminants in preference over common soil cations such as Ca²⁺, Mg²⁺, and K⁺. Rhamnolipid was shown to bind to some soil constituents very strongly including hematite, illite, kaolinite, and montmorillonite. These results indicate that the effectiveness of rhamnolipid in soils with high amounts of iron oxide or clay may be limited due to extensive sorption. Finally, it was found that monorhamnolipid sorbed more strongly than a rhamnolipid mixture containing both monorhamnolipid and dirhamnolipid. This suggests that the use of a biosurfactant mixture may improve the effectiveness of rhamnolipid in the removal of organic and metal contaminants from soil.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Agriculture, Soil Science.; Environmental Sciences.; Engineering, Environmental.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Soil, Water and Environmental Science
Degree Grantor:
University of Arizona
Advisor:
Maier, Raina M.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titlePhysico-chemical factors affecting rhamnolipid (biosurfactant) application for removal of metal contaminants from soilen_US
dc.creatorOchoa Loza, Francisco Javier, 1956-en_US
dc.contributor.authorOchoa Loza, Francisco Javier, 1956-en_US
dc.date.issued1998en_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.abstractContamination of soil and groundwater environments by toxic metals and organic compounds is of major concern because of the potential health hazard posed for humans. Remediation of such sites may require the addition of chemical agents that help in the mobilization of contaminants which are likely to be bound to solid surfaces. Surfactants are one of the agents proposed for addition to enhance the removal of soil-bound contaminants. In this dissertation, a series of laboratory experiments were conducted to investigate constraints to the potential application of a microbially produced surfactant (biosurfactant) for removal of metal contaminants from soil. The first part of the dissertation describes the measurement of stability constants and 13 metals including ten of the metals most frequently found in contaminated sites as well as three of the most common metal cations found in soil, Ca²⁺, Mg ²⁺, and K⁺. The second part of the dissertation describes a series of experiments designed to determine the interaction of the biosurfactant with soil matrix components including clays, metal oxides, and organic matter. The biosurfactant used in this research was monorhamnolipid produced by Pseudomonas aeruginosa ATCC 9027. A mixture of mono- and dirhamnolipid produced by P. aeruginosa UG2 was also used in some cases. Results showed that selectivity of the monorhamnolipid followed the order: Al³⁺ > Cu²⁺ > Pb²⁺ > Cd²⁺ > Zn²⁺ > Fe³⁺ > Hg ²⁺ > Ca²⁺ > Co²⁺ > Ni²⁺ > Mn²⁺ > Mg²⁺ > K⁺. These results suggest that monorhamnolipid binds common metal contaminants in preference over common soil cations such as Ca²⁺, Mg²⁺, and K⁺. Rhamnolipid was shown to bind to some soil constituents very strongly including hematite, illite, kaolinite, and montmorillonite. These results indicate that the effectiveness of rhamnolipid in soils with high amounts of iron oxide or clay may be limited due to extensive sorption. Finally, it was found that monorhamnolipid sorbed more strongly than a rhamnolipid mixture containing both monorhamnolipid and dirhamnolipid. This suggests that the use of a biosurfactant mixture may improve the effectiveness of rhamnolipid in the removal of organic and metal contaminants from soil.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectAgriculture, Soil Science.en_US
dc.subjectEnvironmental Sciences.en_US
dc.subjectEngineering, Environmental.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineSoil, Water and Environmental Scienceen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorMaier, Raina M.en_US
dc.identifier.proquest9912132en_US
dc.identifier.bibrecord.b39124265en_US
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