• 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 Production and Regeneration Of Hybrid Fiber-Ferric Hydroxide Adsorbents For Arsenic Removal From Drinking Water

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    etd_13573_sip1_m.pdf
    Size:
    3.626Mb
    Format:
    PDF
    Download
    Author
    Chaudhary, Binod K.
    Issue Date
    2014
    Keywords
    DFT Modeling
    Ferric Hydroxide
    Homopolymer Polyacrylonitrile
    Kinetics
    Regeneration
    Environmental Engineering
    Arsenic
    Advisor
    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
    Drinking water contaminated with arsenic is a worldwide problem, especially in developing nations. The research presented in this dissertation describes two major goals: development of hybrid homopolymer polyacrylonitrile (PAN)-based sorbents for arsenate removal from drinking water and understanding regeneration of arsenate from ferric hydroxide-based adsorbents. The homopolymer PAN fiber was chemically modified to introduce functional groups using NaOH and hydrazine hydrate (HH) separately, or in combination of both. The modified fibers were characterized using Fourier transform infrared spectroscopy (FTIR) and ion exchange measurements. The ferric hydroxides were impregnated onto functionalized fibers using two iron loading procedures. The best arsenate removal performance was obtained using the simplest pretreatment procedure of soaking in 10% NaOH at 95 °C for ninety min, followed by precipitation coating of ferric hydroxide. This suggests that adsorbents based on a low-cost PAN fabric may be produced in developing areas of the world where commercial products may not be available. A density functional theory (DFT) molecular modeling was used to compare free energies of reactions and activation barriers in the formation of arsenate-ferric hydroxide complexes. Slow kinetics associated with arsenate adsorption and desorption attributed to the high activation barriers in forming and breaking bonds with the ferric hydroxides. Another aspect of regeneration study focused on the effects of underlying properties of the ferric hydroxides-loaded adsorbents on arsenate recovery. The arsenate loaded ferric hydroxide adsorbent containing no or weak base functionalities can be regenerated using NaOH, while addition of NaCl to NaOH solution is required for same recovery of arsenate from the adsorbents containing strong base anion exchange functionalities. Moreover, the irreversible fraction of arsenate on the adsorbent can be reduced by increasing the concentration of NaOH. Thus, understanding arsenate desorption kinetics and effects of support properties of ferric hydroxide-based adsorbents are important for environmental fate of arsenate and in designing adsorption systems for removing arsenate from potable water.
    Type
    text
    Electronic Dissertation
    Degree Name
    Ph.D.
    Degree Level
    doctoral
    Degree Program
    Graduate College
    Environmental Engineering
    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.