TY - JOUR
T1 - Protonation enthalpies of metal oxides from high temperature electrophoresis
AU - Rodriguez-Santiago, Victor
AU - Fedkin, Mark V.
AU - Lvov, Serguei N.
N1 - Funding Information:
The authors gratefully acknowledge the financial support for this work by the National Science Foundation (EAR 07-32559) and the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences, US Department of Energy, through a grant to Oak Ridge National Laboratory (DE-AC05-00OR22725).
PY - 2012/4/1
Y1 - 2012/4/1
N2 - Surface protonation reactions play an important role in the behavior of mineral and colloidal systems, specifically in hydrothermal aqueous environments. However, studies addressing the reactions at the solid/liquid interface at temperatures above 100°C are scarce. In this study, newly and previously obtained high temperature electrophoresis data (up to 260°C) - zeta potentials and isoelectric points - for metal oxides, including SiO 2, SnO 2, ZrO 2, TiO 2, and Fe 3O 4, were used in thermodynamic analysis to derive the standard enthalpies of their surface protonation. Two different approaches were used for calculating the protonation enthalpy: one is based on thermodynamic description of the 1-pKa model for surface protonation, and another one - on a combination of crystal chemistry and solvation theories which link the relative permittivity of the solid phase and the ratio of the Pauling bond strength and bond length to standard protonation enthalpy. From this analysis, two expressions relating the protonation enthalpy to the relative permittivity of the solid phase were obtained.
AB - Surface protonation reactions play an important role in the behavior of mineral and colloidal systems, specifically in hydrothermal aqueous environments. However, studies addressing the reactions at the solid/liquid interface at temperatures above 100°C are scarce. In this study, newly and previously obtained high temperature electrophoresis data (up to 260°C) - zeta potentials and isoelectric points - for metal oxides, including SiO 2, SnO 2, ZrO 2, TiO 2, and Fe 3O 4, were used in thermodynamic analysis to derive the standard enthalpies of their surface protonation. Two different approaches were used for calculating the protonation enthalpy: one is based on thermodynamic description of the 1-pKa model for surface protonation, and another one - on a combination of crystal chemistry and solvation theories which link the relative permittivity of the solid phase and the ratio of the Pauling bond strength and bond length to standard protonation enthalpy. From this analysis, two expressions relating the protonation enthalpy to the relative permittivity of the solid phase were obtained.
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U2 - 10.1016/j.jcis.2012.01.002
DO - 10.1016/j.jcis.2012.01.002
M3 - Article
C2 - 22285101
AN - SCOPUS:84857046021
SN - 0021-9797
VL - 371
SP - 136
EP - 143
JO - Journal of Colloid And Interface Science
JF - Journal of Colloid And Interface Science
IS - 1
ER -