Kinetics of ciprofloxacin degradation by ozonation : effects of natural organic matter, the carbonate system, and pH

The presence of pharmacologically active and persistent compounds in drinking water sources is an environmental and public health concern. Sources of pharmaceuticals in the aquatic environment include wastewater treatment plant effluents and veterinary use. Antibiotics are of special concern because...

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Main Author: Marron, Corin Ann
Format: Others
Language:English
Published: 2010
Subjects:
Online Access:http://hdl.handle.net/2152/ETD-UT-2010-08-2027
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spelling ndltd-UTEXAS-oai-repositories.lib.utexas.edu-2152-ETD-UT-2010-08-20272015-09-20T16:56:26ZKinetics of ciprofloxacin degradation by ozonation : effects of natural organic matter, the carbonate system, and pHMarron, Corin AnnOzonationPharmaceuticalsCiprofloxacinWater treatmentNatural organic matterThe presence of pharmacologically active and persistent compounds in drinking water sources is an environmental and public health concern. Sources of pharmaceuticals in the aquatic environment include wastewater treatment plant effluents and veterinary use. Antibiotics are of special concern because of their role in the spread of bacterial resistance. Conventional drinking water treatment processes are often ineffective for removing trace organic contaminants. Ozonation processes have demonstrated the ability to remove pharmaceutical compounds from drinking water supplies. During the ozonation of drinking water, the primary oxidants are ozone and hydroxyl radicals formed during the decomposition of ozone. Both oxidants contribute to the removal of pharmaceutical compounds; however, the relative rates of destruction by these two oxidants depends on the treatment operating conditions, the background water chemistry and the structure and reactivity of the target compound. This study investigated the relative impact of natural water characteristics, such as pH, the carbonate system, and natural organic matter, on the removal of the fluoroquinolone antibiotic ciprofloxacin by ozonation processes. Rate constants for k"O3, Cip obtained at pH 7 were approximately one order of magnitude higher than at pH 5 because ciprofloxacin changes from a positively charged cation to a neutral species over this pH range. The results showed that there was very little variation of the rate constants for ciprofloxacin oxidation by O₃ or hydroxyl radicals regardless of the carbonate concentration or the presence of the two organic matters studied in this research. Typical values for k"O3, Cip and k"HO°, Cip obtained at pH 7 ranged between 1.49x10⁴ and 1.64x10⁴ M⁻¹s⁻¹ and 1.29x10¹⁰ to 1.80x10¹⁰ M⁻¹s⁻¹, respectively. However, the presence of carbonate and other hydroxyl radical scavengers did have an impact on O₃ and hydroxyl radical exposure. The relative impact of these two oxidants changed depending on the pH of the system and the presence of carbonate and natural organic matter.text2010-12-21T21:31:42Z2010-12-21T21:31:48Z2010-12-21T21:31:42Z2010-12-21T21:31:48Z2010-082010-12-21August 20102010-12-21T21:31:48Zthesisapplication/pdfhttp://hdl.handle.net/2152/ETD-UT-2010-08-2027eng
collection NDLTD
language English
format Others
sources NDLTD
topic Ozonation
Pharmaceuticals
Ciprofloxacin
Water treatment
Natural organic matter
spellingShingle Ozonation
Pharmaceuticals
Ciprofloxacin
Water treatment
Natural organic matter
Marron, Corin Ann
Kinetics of ciprofloxacin degradation by ozonation : effects of natural organic matter, the carbonate system, and pH
description The presence of pharmacologically active and persistent compounds in drinking water sources is an environmental and public health concern. Sources of pharmaceuticals in the aquatic environment include wastewater treatment plant effluents and veterinary use. Antibiotics are of special concern because of their role in the spread of bacterial resistance. Conventional drinking water treatment processes are often ineffective for removing trace organic contaminants. Ozonation processes have demonstrated the ability to remove pharmaceutical compounds from drinking water supplies. During the ozonation of drinking water, the primary oxidants are ozone and hydroxyl radicals formed during the decomposition of ozone. Both oxidants contribute to the removal of pharmaceutical compounds; however, the relative rates of destruction by these two oxidants depends on the treatment operating conditions, the background water chemistry and the structure and reactivity of the target compound. This study investigated the relative impact of natural water characteristics, such as pH, the carbonate system, and natural organic matter, on the removal of the fluoroquinolone antibiotic ciprofloxacin by ozonation processes. Rate constants for k"O3, Cip obtained at pH 7 were approximately one order of magnitude higher than at pH 5 because ciprofloxacin changes from a positively charged cation to a neutral species over this pH range. The results showed that there was very little variation of the rate constants for ciprofloxacin oxidation by O₃ or hydroxyl radicals regardless of the carbonate concentration or the presence of the two organic matters studied in this research. Typical values for k"O3, Cip and k"HO°, Cip obtained at pH 7 ranged between 1.49x10⁴ and 1.64x10⁴ M⁻¹s⁻¹ and 1.29x10¹⁰ to 1.80x10¹⁰ M⁻¹s⁻¹, respectively. However, the presence of carbonate and other hydroxyl radical scavengers did have an impact on O₃ and hydroxyl radical exposure. The relative impact of these two oxidants changed depending on the pH of the system and the presence of carbonate and natural organic matter. === text
author Marron, Corin Ann
author_facet Marron, Corin Ann
author_sort Marron, Corin Ann
title Kinetics of ciprofloxacin degradation by ozonation : effects of natural organic matter, the carbonate system, and pH
title_short Kinetics of ciprofloxacin degradation by ozonation : effects of natural organic matter, the carbonate system, and pH
title_full Kinetics of ciprofloxacin degradation by ozonation : effects of natural organic matter, the carbonate system, and pH
title_fullStr Kinetics of ciprofloxacin degradation by ozonation : effects of natural organic matter, the carbonate system, and pH
title_full_unstemmed Kinetics of ciprofloxacin degradation by ozonation : effects of natural organic matter, the carbonate system, and pH
title_sort kinetics of ciprofloxacin degradation by ozonation : effects of natural organic matter, the carbonate system, and ph
publishDate 2010
url http://hdl.handle.net/2152/ETD-UT-2010-08-2027
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