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Electrochemical phase diagrams for aqueous redox systems

Zappia, Michael Joseph
http://rave.ohiolink.edu/etdc/view?acc_num=case1054840226

Abstract Details

1990, Doctor of Philosophy, Case Western Reserve University, Chemical Engineering.
An entirely new type of electrochemical phase diagram, the electron number diagram, has been discovered. The theoretical foundation for the electron number diagram and its relationship to conventional potential-pH diagrams have been developed. Electron number diagrams are obtained by a thermodynamic transformation in which potential is replaced by a measure of the number of electrons. The chemical potential of electrons and the number of electrons are conjugate thermodynamic variables. The areas in which electron number diagrams provide information complementary to and in addition to that from conventional potential-pH diagrams have been identified. Experimental electron number diagrams have been constructed for the aqueous sulfur system. Two-dimensional sections of the three-dimensional electron number diagram at both constant pH and constant electron number have been determined and compared with the sections computed from theory. Agreement between the computed and measured diagrams has been found. A rigorous thermodynamic theory for complex aqueous redox systems has been developed and used for interpretation of the various types of electrochemical phase diagrams. The dimensionality of potential-pH and electron number diagrams has been related to the Gibbs phase rule analysis of aqueous redox systems. An efficient computational method, based on the theoretical analysis of complex aqueous redox systems, has been developed. The equations describing the equilibrium composition are obtained from a minimum set of formation reactions. The formation reactions use a set of reactants (components) whose chemical potentials are chosen to be the independent variables in the computation. This procedure permits the sequential rather than simultaneous solution of the equation set in the case of ideal solutions. Efficient stability criteria, obtained from theory, here used to determine the stability of solid phases. The algorithm was implemented on IBM PCs and compatible computers. Electron number, potential-pH and chemical potential diagrams have been computed for a variety of complex aqueous systems, including the following systems containing two active redox elements: the aqueous Cd-Te system; the aqueous Ga-As system; and the aqueous U-C system.
John Angus (Advisor)
248 p.
Engineering, Chemical
electrochemical phase diagrams aqueous redox systems

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Citations

  • Zappia, M. J. (1990). Electrochemical phase diagrams for aqueous redox systems [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1054840226

    APA Style (7th edition)

  • Zappia, Michael. Electrochemical phase diagrams for aqueous redox systems. 1990. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1054840226.

    MLA Style (8th edition)

  • Zappia, Michael. "Electrochemical phase diagrams for aqueous redox systems." Doctoral dissertation, Case Western Reserve University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=case1054840226

    Chicago Manual of Style (17th edition)

case1054840226
635
© 1990, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.