KU ScholarWorks

  • myKU
  • Email
  • Enroll & Pay
  • KU Directory
    • Login
    View Item 
    •   KU ScholarWorks
    • Engineering
    • Civil, Environmental & Architectural Engineering Scholarly Works
    • View Item
    •   KU ScholarWorks
    • Engineering
    • Civil, Environmental & Architectural Engineering Scholarly Works
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Calorimetric determination of the enthalpies of formation of hydrotalcite-like solids and their use in the geochemical modeling of metals in natural waters

    Thumbnail
    View/Open
    Allada_calorimetric_determination2006.pdf (321.3Kb)
    Issue Date
    2006
    Author
    Allada, Rama kumar
    Peltier, Edward
    Navrotsky, Alexandra
    Casey, William H.
    Johnson, C. Annette
    Berbeco, Hillary Thompson
    Sparks, Donald L.
    Publisher
    Clay Minerals Society
    Type
    Article
    Article Version
    Scholarly/refereed, publisher version
    Metadata
    Show full item record
    Abstract
    Interest in hydrotalcite-like compounds has grown due to their role in controlling the mobility of aqueous metals in the environment as well as their use as catalysts, catalyst precursors and specialty chemicals. Although these materials have been studied in a number of contexts, little is known of their thermodynamic properties. High-temperature oxide melt solution calorimetry was used to measure the standard enthalpy of formation for compounds M(II)1−xAlx(OH)2(CO3)x/2·mH2O (0.2 < x < 0.4, M(II) = Mg, Co, Ni and Zn). The enthalpy of formation of these compounds from the relevant single cation phases was also determined. The formation of HTLCs results in a 5–20 kJ/mol enthalpy stabilization from the single cation hydroxides and carbonates and water. The data are correlated to two variables: the ratio of divalent to trivalent cation in the solid (M(II)/Al) and the identity of the divalent cation. It was observed that the M(II)/Al ratio exerts a minor influence on the enthalpy of formation from single-cation phases, while greater differences in stabilization resulted from changes in the chemical nature of the divalent cation. However, the data do not support any statistically significant correlation between the composition of HTLCs and their heats of formation. Equilibrium geochemical calculations based upon the thermodynamic data illustrate the effect of HTLCs on the speciation of metals in natural waters. These calculations show that, in many cases, HTLCs form even in waters that are undersaturated with respect to the individual divalent metal hydroxides and carbonates. Phase diagrams and stability diagrams involving Ni-bearing HTLCs and the single-cation components are presented. The Ni(II) concentration as a function of pH as well as the stability diagram for the equilibrium among minerals in the CaO-NiO-Al2O3-SiO2-CO2-H2O system at 298 K are plotted.
    Description
    This is the published version. Copyright 2006 Clay Minerals Society
    URI
    http://hdl.handle.net/1808/18927
    DOI
    https://doi.org/10.1346/CCMN.2006.0540401
    Collections
    • Civil, Environmental & Architectural Engineering Scholarly Works [75]
    Citation
    Allada, Rama Kumar, Edward Peltier, Alexandra Navrotsky, William H. Casey, C. Annette Johnson, Hillary Thompson Berbeco, and Donald L. Sparks. "Calorimetric Determination of the Enthalpies of Formation of Hydrotalcite-like Solids and Their Use in the Geochemical Modeling of Metals in Natural Waters." Clays Clay Miner. Clays and Clay Minerals 54.4 (2006): 409-17. http://dx.doi.org/10.1346/CCMN.2006.0540401

    Items in KU ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.


    We want to hear from you! Please share your stories about how Open Access to this item benefits YOU.


    Contact KU ScholarWorks
    785-864-8983
    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    785-864-8983

    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    Image Credits
     

     

    Browse

    All of KU ScholarWorksCommunities & CollectionsThis Collection

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Contact KU ScholarWorks
    785-864-8983
    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    785-864-8983

    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    Image Credits
     

     

      Contact KU ScholarWorks
    Lawrence, KS | Maps
     
    • Academics
    • Admission
    • Alumni
    • Athletics
    • Campuses
    • Giving
    • Jobs

    The University of Kansas prohibits discrimination on the basis of race, color, ethnicity, religion, sex, national origin, age, ancestry, disability, status as a veteran, sexual orientation, marital status, parental status, gender identity, gender expression and genetic information in the University’s programs and activities. The following person has been designated to handle inquiries regarding the non-discrimination policies: Director of the Office of Institutional Opportunity and Access, IOA@ku.edu, 1246 W. Campus Road, Room 153A, Lawrence, KS, 66045, (785)864-6414, 711 TTY.

     Contact KU
    Lawrence, KS | Maps