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Thermo- and Zero-Valent Iron-Activated Persulfate Oxidation of 3,5,6-Trichloro-2-pyridinol in an Aquatic System

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Date Issued:
2018
Abstract/Description:
The compound 3,5,6-trichloro-2-pyridinol (TCPy), a metabolite of the broad-spectrumorganophosphorous insecticide chlorpyrifos, is both more persistent and more water soluble thanits parent compound. This difference, which allows TCPy to more readily leach into surface waterand groundwater, has led to widespread contamination of TCPy in soils and aquatic environments.In this study, the degradation of TCPy by sulfate radicals was evaluated using zero valent ironactivatedpersulfate systems and heat activated persulfate system in aqueous media. Responsesurface methodology coupled with Box-Behnken design was applied in these studies to evaluatethe effects of the independent variables on the mineralization of TCPy by both systems. In eachsystem, the interactions, coefficients, and residuals of these variables were statically evaluated byAnalysis of variance. Results indicate that both systems can effectively oxidized TCPy in water.While ZV/PS exhibited a high mineralization rate of TCPy up to 81.1%, TCPy was completelymineralized in heat activated PS system. The reaction kinetics of the degradation process wereexamined as functions of experimental parameters in each system and the result revealed that theoxidation of TCPy in both systems followed a pseudo-first-order model under all conditions tested.Radical scavenging tests indicated that sulfate radicals are the predominated species in zero valentiron activated persulfate system, whereas hydroxyl radicals are the predominated species in heatactivated persulfate system. The presence of chloride, sulfate and phosphate anions showednegligible effects on TCPy oxidation by heat activated PS system. The degradation pathways ofTCPy were proposed based on the products identified by GC-MS. Calculated ?G values usingdensity functional theory agreed with the proposed experimental pathway.
Title: Thermo- and Zero-Valent Iron-Activated Persulfate Oxidation of 3,5,6-Trichloro-2-pyridinol in an Aquatic System.
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Name(s): Mogharbel, Roaa, Author
Yestrebsky, Cherie, Committee Chair
Beazley, Melanie, Committee Member
Zou, Shengli, Committee Member
Legron-Rodriguez, Tamra, Committee Member
Randall, Andrew, Committee Member
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2018
Publisher: University of Central Florida
Language(s): English
Abstract/Description: The compound 3,5,6-trichloro-2-pyridinol (TCPy), a metabolite of the broad-spectrumorganophosphorous insecticide chlorpyrifos, is both more persistent and more water soluble thanits parent compound. This difference, which allows TCPy to more readily leach into surface waterand groundwater, has led to widespread contamination of TCPy in soils and aquatic environments.In this study, the degradation of TCPy by sulfate radicals was evaluated using zero valent ironactivatedpersulfate systems and heat activated persulfate system in aqueous media. Responsesurface methodology coupled with Box-Behnken design was applied in these studies to evaluatethe effects of the independent variables on the mineralization of TCPy by both systems. In eachsystem, the interactions, coefficients, and residuals of these variables were statically evaluated byAnalysis of variance. Results indicate that both systems can effectively oxidized TCPy in water.While ZV/PS exhibited a high mineralization rate of TCPy up to 81.1%, TCPy was completelymineralized in heat activated PS system. The reaction kinetics of the degradation process wereexamined as functions of experimental parameters in each system and the result revealed that theoxidation of TCPy in both systems followed a pseudo-first-order model under all conditions tested.Radical scavenging tests indicated that sulfate radicals are the predominated species in zero valentiron activated persulfate system, whereas hydroxyl radicals are the predominated species in heatactivated persulfate system. The presence of chloride, sulfate and phosphate anions showednegligible effects on TCPy oxidation by heat activated PS system. The degradation pathways ofTCPy were proposed based on the products identified by GC-MS. Calculated ?G values usingdensity functional theory agreed with the proposed experimental pathway.
Identifier: CFE0007762 (IID), ucf:52386 (fedora)
Note(s): 2018-12-01
Ph.D.
Sciences, Chemistry
Doctoral
This record was generated from author submitted information.
Subject(s): 3 -- 5 -- 6-trichloro-2-pyridinol
persulfate
sulfate radical
Zero valent iron
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFE0007762
Restrictions on Access: public 2019-06-15
Host Institution: UCF

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