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Please use this identifier to cite or link to this item: http://apo.ansto.gov.au/dspace/handle/10238/335

Title: Thermochemical data for environmentally-relevant elements.
Authors: Markich, SJ
Brown, PL
Keywords: Organic acids
Geochemistry
Computer codes
Stability
Issue Date: Dec-1999
Publisher: Australian Nuclear Science and Technology Organisation
Citation: Markich, S. J. & Brown, P. L. (1999). Thermochemical data (log K) for environmentally-relevant elements : 1. H, Na, K, Ca, Mg, Fe, Mn, U, A1, Pb, Zn, Cu and Cd with model fulvic acid (Aspartate, citrate, malonate, salicylate and tricarballyate). Australian Nuclear Science and Technology Organisation, Lucas Heights Science and Technology Centre, Lucas Heights, N.S.W
Abstract: This study provides an extensive stability constant (log K) database suitable for calculating the speciation of selected environmentally-relevant elements (H Na K Ca Mg Fe Mn U Al Pb Zn Cu and Cd) in an aqueous system where a model fulvic acid (comprising aspartic citric malonic salicylic and tricarballylic acids) is used to simulate metal binding by dissolved organic material Stability constants for inorganic metal complexes and minerals were selected primarily from critical literature complications and/or reviews. In contrast few critically evaluated data were available for metal complexes with aspartic citric, malonic, salicylic and tricarballylic acids. Consequently, data from original research articles were carefully evaluated and compiled as part of the study, following defined selection criteria. To meet the objective of compiling a comprehensive and reliable database of stability constants, all relevant equilibria and species, ranging from simple binary metal complexes to more complex ternary, and even quaternary, metal complexes were included where possible. In addition to the selection of stability constants from empirical sources, estimates of stability constants were performed when this could be done reliably, based on the unified theory of metal ion complexation and/or linear free energy relationships. The stability constants are given as common logarithms (log10) in the form required by the HARPHRQ geochemical code and refer to the standard state, i.e. 298.15 k (25—C), 106 Pa (1 atm) and, for all species, infinite dilution (ionic strength = 0 moI L-1). In addition to the compilation of stability constant data, an overview is given of geochemical speciation modeling in aqueous systems and available conceptual models of metal binding by humic substances.
URI: http://apo.ansto.gov.au/dspace/handle/10238/335
ISBN: 0642599726
ISSN: 10307746
Appears in Collections:Scientific and Technical Reports

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