• Login
    View Item 
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of UA Campus RepositoryCommunitiesTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournalThis CollectionTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournal

    My Account

    LoginRegister

    About

    AboutUA Faculty PublicationsUA DissertationsUA Master's ThesesUA Honors ThesesUA PressUA YearbooksUA CatalogsUA Libraries

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Understanding electrochemical inactivation of contaminants in water

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    azu_td_hy_e9791_2004_163_sip1_w.pdf
    Size:
    5.418Mb
    Format:
    PDF
    Description:
    azu_td_hy_e9791_2004_163_sip1_w.pdf
    Download
    Author
    Wang, Jiankang
    Issue Date
    2004
    Keywords
    Hydrology.
    Electrolytic reduction.
    Water -- Pollution.
    Committee Chair
    Farrell, James
    
    Metadata
    Show full item record
    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
    This research investigated the mechanism, kinetics, and feasibility of chlorinated aliphatic compounds inactivation by electrochemical reduction using nickel and iron electrodes. Reactions of trichloroethylene (TCE) and tetrachloroethylene (PCE) with zerovalent iron were investigated to determine the role of atomic hydrogen in their reductive dechlorination using Tafel analysis and electrochemical impedance spectroscopy (EIS). Comparison of iron corrosion rates with those for TCE reaction showed that TCE reduction occurred almost exclusively via atomic hydrogen at low pH values and via atomic hydrogen and direct electron transfer at neutral pH values. In contrast, reduction of PCE occurred primarily via direct electron transfer at both low and neutral pH values. The EIS data showed that all the rate limitations for TCE and PCE dechlorination occurred during the transfer of the first two electrons. Carbon tetrachloride (CT) reductive dechlorination was studied at a nickel rotating disk electrode using chronoampermetry (CA) and EIS. Only trace levels of methylene chloride and chloromethane were produced, indicating that sequential hydrogenolysis was not the predominant pathway for methane production. EIS showed that the ratelimiting step for CT reduction was the transfer of the first electron to a physically adsorbed CT molecule. The feasibility of an electrochemical reductive dechlorination method for removing CT from potable water was carried out in a flow-through reactor using bare and polymer coated porous nickel electrodes. Destruction of half-life values for CT with the bare nickel electrode ranged from 3.5 to 5.8 minutes for electrode potentials ranging from -652 to -852 mV with respect to the standard hydrogen electrode (SHE). Faradic current efficiencies could be increased by 100 to 360% by coating the electrode with a silicone polymer. This research also investigated electrochemical oxidation of triclosan, a biocidal agent, using Ebonex® and boron-doped diamond (BDD) film anodes. Product analysis showed that breaking the ether linkage was easier than opening the aromatic ring. Microtox® testing indicated that residual triclosan accounted for nearly all the toxicity in the treated water, despite the fact that chlorinated byproduct concentrations were significantly higher than those of triclosan itself.
    Type
    Dissertation-Reproduction (electronic)
    text
    Degree Name
    Ph.D.
    Degree Level
    doctoral
    Degree Program
    Chemical and Environmental Engineering
    Graduate College
    Degree Grantor
    University of Arizona
    Collections
    Dissertations

    entitlement

     
    The University of Arizona Libraries | 1510 E. University Blvd. | Tucson, AZ 85721-0055
    Tel 520-621-6442 | repository@u.library.arizona.edu
    DSpace software copyright © 2002-2017  DuraSpace
    Quick Guide | Contact Us | Send Feedback
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.