• 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

    Thermodynamic and isotopic systematics of chromium chemistry

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    azu_td_hy_e9791_1996_276_sip1_w.pdf
    Size:
    14.16Mb
    Format:
    PDF
    Description:
    azu_td_hy_e9791_1996_276_sip1_w.pdf
    Download
    Author
    Ball, James William,1945-
    Issue Date
    1996
    Keywords
    Hydrology.
    Chromium.
    Ion exchange chromatography.
    Committee Chair
    Bassett, Randy
    
    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 investigation has produced four major results: (1) Thermodynamic properties of chromium metal, aqueous ions, hydrolysis species, oxides and hydroxides were compiled. Data were critically evaluated, some data were recalculated, and thermodynamic properties were selected. (2) A method was developed for separating chromium from its natural water matrix using sequential anion and cation exchange chromatography. (3) A method for determining the ⁵³Cr/⁵²Cr ratio using solid-source thermal ionization mass spectrometry with the silica gel-boric acid ionization- - enhancement technique was developed. (4) Ground water samples from six locations were analyzed for their ⁵³Cr/⁵²Cr ratio using the above methods. Results from carefully measured electromotive force (emf) values for the reduction of Cr³⁺ to Cr²⁺ were recalculated for compatibility with the infinite dilution standard state, and a revised ∆G°(f) for Cr²⁺(aq) was calculated. Equilibrium constants for chromium(III) hydrolysis were taken from Rai, et al. (1987) and for chromium(VI) hydrolysis from Palmer, et al. (1987). The ion exchange method is based on retention of chromium(VI) on strongly basic anion exchange resin at pf1 4 and its reductive elution with 2N HNO₃ . Chromium(III) is retained on strongly acidic cation exchange resin at pH 1.3 and eluted with 5N HNO₃. Possible interferents include metals that form both oxyanions and cations. High-purity reagents and containers made of rigorously cleanable noncontaminating materials are required. Samples for mass spectrometry are pretreated with aqua regia and concentrated nitric acid, then mixed with silica and boric acid and transferred to the tantalum filament of a stainless steel and glass sample holder. The ⁵³Cr/⁵²Cr ratio was measured to avoid isobaric interferences with iron. To be significantly different from each other, isotopic signatures must differ by at least 0.5 per mil. Samples from six locations were examined for their ⁵³Cr/⁵²Cr ratio. For the samples with natural origin, the spread in δ⁵³Cr values of-2.0 to +3.0 per mil suggests that samples of chromium derived from differing source materials or from different geographic locations have distinct isotopic signatures. Conclusions regarding source-related variations in the isotopic signature of contaminant chromium are problematic, because specific information about the respective source materials is lacking.
    Type
    Dissertation-Reproduction (electronic)
    text
    Degree Name
    Ph. D.
    Degree Level
    doctoral
    Degree Program
    Hydrology and Water Resources
    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.