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Kinetics of aluminum-fulvic acid complexation in acidic waters

Journal Article · · Environ. Sci. Technol.; (United States)
DOI:https://doi.org/10.1021/es00160a011· OSTI ID:6502870

A fluorescence technique has been used to study the complex formation kinetics of aluminum with a single metal-free fulvic acid isolated from an Adirondack Mountain forest soil. In the pH range of 3.0-4.5, two kinetically distinguishable components of the fulvic acid mixture have been identified, which define two types of average aluminum binding sites. Both fulvic acid average sites conform to a bidentate chelating binding site kinetic analysis, from which rate and equilibrium parameters have been obtained. From comparison of rate and equilibrium constants of aluminum-salicyclic acid complexation, the authors conclude that the faster reacting component of fulvic acid probably contains salicyclic acid type aluminum binding sites. Results are also compared with those of an aluminum-fluoride kinetic study. Fulvic acid and fluoride react with aluminum by the same mechanism and therefore have the same pH dependence. The dependence of the rate on temperature is, however, quite different for the two reactions. The environmental implications of these findings are discussed. 45 references, 5 figures, 6 tables.

Research Organization:
Univ. of Maine, Orono
OSTI ID:
6502870
Journal Information:
Environ. Sci. Technol.; (United States), Journal Name: Environ. Sci. Technol.; (United States) Vol. 21:6; ISSN ESTHA
Country of Publication:
United States
Language:
English