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Title: Evaluation of internally consistent parameters for the triple-layer model by the systematic analysis of oxide surface titration data

Journal Article · · Geochimica et Cosmochimica Acta
;  [1]
  1. Johns Hopkins Univ., Baltimore, MD (United States)

Systematic analysis of surface titration data from the literature has been performed for ten oxides (anatase, hematite, goethite, rutile, amorphous silica, quartz, magnetite, {delta}-MnO{sub 2}, corundum, and {gamma}-alumina) in ten electrolytes (LiNO{sub 3}, NaNO{sub 3}, KNO{sub 3}, CsNO{sub 3}, LiCl, NaCl, KCl, CsCl, Nal, and NaClO{sub 4}) over a wide range of ionic strengths (0.001 M-2.9 M) to establish adsorption equilibrium constants and capacitances consistent with the triple-layer model of surface complexation. Experimental data for the same mineral in different electrolytes and data for a given mineral/electrolyte system from various investigators have been compared. In this analysis, the surface protonation constants (K{sub s,1} and K{sub s,2}) were calculated by combining predicted values of {Delta}pK(log K{sub s,2} - log K{sub s,1}) with experimental points of zero charge; site-densities were obtained from tritium-exchange experiments reported in the literature, and the outer-layer capacitance (C{sub 2}) was set at 0.2 F {center_dot} m{sup -2}. 98 refs., 8 figs., 27 tabs.

DOE Contract Number:
FG02-96ER14616
OSTI ID:
576314
Journal Information:
Geochimica et Cosmochimica Acta, Vol. 61, Issue 14; Other Information: PBD: Jul 1997
Country of Publication:
United States
Language:
English