Show simple item record

dc.contributor.advisorLawler, Desmond F.en
dc.contributor.advisorKatz, Lynn Ellenen
dc.creatorBlaney, Lee Michaelen
dc.date.accessioned2011-09-19T16:50:50Zen
dc.date.available2011-09-19T16:50:50Zen
dc.date.issued2011-08en
dc.date.submittedAugust 2011en
dc.identifier.urihttp://hdl.handle.net/2152/ETD-UT-2011-08-3882en
dc.descriptiontexten
dc.description.abstractAnthropogenically-derived substances, including pharmaceuticals and personal care products, endocrine-disrupting chemicals, and pesticides, are increasingly being detected in drinking water supplies and wastewater effluents. Concerns over the presence of these compounds in water supplies include their ability to impart toxicological activity, their capacity to spread antibiotic resistance, and their potential to affect cell-signaling processes. For these reasons, water treatment processes geared towards removal of these trace organic contaminants are vital. In this work, ozone was used to treat four pharmaceutical contaminants: ciprofloxacin, cyclophosphamide, erythromycin, and ifosfamide. Ciprofloxacin and erythromycin are antibiotic/antimicrobial compounds, and cyclophosphamide and ifosfamide are chemotherapy agents. Ozone effectively transformed all four pharmaceuticals, even in the presence of background natural organic matter, which exerts a considerable ozone demand. The apparent rate constants for the reaction of the pharmaceuticals with ozone at pH 7 were determined: 3.03 M-1s-1 for cyclophosphamide; 7.38 M-1s-1 for ifosfamide; 1.57×104 M-1s-1 for ciprofloxacin; and 7.18×104 M-1s-1 for erythromycin. Cyclophosphamide and ifosfamide, which do not react quickly with ozone, exhibited high rate constants (2.7×109 M-1s-1) for transformation by hydroxyl radicals, which are formed through ozone decomposition. Nevertheless, complete removal of cyclophosphamide and ifosfamide was achievable using a novel continuous aqueous ozone addition reactor and an ozone-based advanced oxidation process (peroxone). In ozone-based processes, pharmaceuticals are systematically transformed via complex oxidative pathways towards CO2, H2O, and the oxidized forms of other elements. Intermediate oxidation products containing oxygen atoms or hydroxyl groups substituted into the chemical structure of the parent pharmaceutical were identified using liquid chromatography-mass spectrometry (LC-MS). Given the structural similarity of intermediate oxidation products to the parent pharmaceuticals, an antimicrobial activity assay was employed to monitor the removal of pharmacological activity associated with ciprofloxacin, erythromycin, and their respective intermediate oxidation products throughout treatment. For solutions containing ciprofloxacin or erythromycin, ozone was able to completely eliminate the corresponding antimicrobial activity. Ciprofloxacin intermediate oxidation products were pharmacologically active; however, erythromycin’s intermediate products did not contribute to the residual antimicrobial activity. These results suggest that the design of conventional and advanced ozone-based processes must incorporate ozone demand from background organic matter and account for destruction of pharmacologically active intermediates.en
dc.format.mimetypeapplication/pdfen
dc.language.isoengen
dc.subjectOzoneen
dc.subjectPharmaceuticalsen
dc.subjectWater treatmenten
dc.subjectNatural organic matteren
dc.subjectResidual pharmacological activityen
dc.titleOxidation of pharmaceuticals : impacts of natural organic matter and elimination of residual pharmacological activityen
dc.date.updated2011-09-19T16:51:10Zen
dc.identifier.slug2152/ETD-UT-2011-08-3882en
dc.contributor.committeeMemberLiljestrand, Howard M.en
dc.contributor.committeeMemberRichburg, John H.en
dc.contributor.committeeMemberSpeitel Jr., Gerald E.en
dc.contributor.committeeMemberKirisits, Mary Joen
dc.description.departmentCivil, Architectural, and Environmental Engineeringen
dc.type.genrethesisen
thesis.degree.departmentCivil, Architectural, and Environmental Engineeringen
thesis.degree.disciplineCivil Engineeringen
thesis.degree.grantorUniversity of Texas at Austinen
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophyen


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record