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Coprecipitation of Iron and Aluminum During Titration of Mixed AP+, Fe3+, and Fe2+ Solutions

Published online by Cambridge University Press:  02 April 2024

P. M. Bertsch ,
W. P. Miller ,
M. A. Anderson  and
L. W. Zelazny
P. M. Bertsch
Affiliation:
Division of Biogeochemistry, Savannah River Ecology Laboratory, University of Georgia, P.O. Drawer E, Aiken, South Carolina 29801
W. P. Miller
Affiliation:
Department of Agronomy, University of Georgia, Athens, Georgia 30602
M. A. Anderson
Affiliation:
Department of Agronomy, Soil, and Environmental Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
L. W. Zelazny
Affiliation:
Department of Agronomy, Soil, and Environmental Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
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Abstract

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Potentiometric titration analysis was used to examine the hydrolysis behavior of Fe2+ Fe3+, and Al3+ in pure solution and in mixture, in order to evaluate the potential for coprecipitation and mixed solid-phase formation. Mixtures of Fe3+ and Al3+ did not interact during neutralization; base consumed in their respective buffer regions was equivalent to the total metal added. Fe2+-Al3+ solutions, however, showed excess base consumption in the Al3+ buffer region, indicating hydrolysis of Fe2+ at lower than normal pH. Ferric/ferrous iron analyses of systems at the Al endpoint (pH 5.5) showed amounts of oxidized Fe equivalent to the excess base consumption (∼10% of total Fe), with substantial amounts of Fe2+ sorbed to or occluded within Al polymers present. Increased electrolyte levels or the presence of SO42- inhibited oxidation and sorption of Fe2+ on Al surfaces, suggesting that Fe hydrolysis and oxidation was catalyzed at the surfaces. Increasing Al3+: Fe2+ ratios in the titrated solutions also increased the amount of Fe2+ coprecipitation, supporting a surface-mediated reaction mechanism. Ferrous iron oxidation was sensitive to O2 levels, which also affected the amount of coprecipitation. These findings suggest that surface-facilitated oxidation of Fe2+ may be important in the formation of mixed Fe-Al mineral phases in dilute soil solutions.

Keywords

AluminumHydrolysisIronOxidationPotentiometrie titration
Type
Research Article
Information
Clays and Clay Minerals , Volume 37 , Issue 1 , February 1989 , pp. 12 - 18
Copyright
Copyright © 1989, The Clay Minerals Society

References

Arden, T. V., 1950 The solubility of ferrous and ferrosic hydroxides J. Chem. Soc 882 – 885.CrossRefGoogle Scholar
Baes, C. P. and Mesmer, R. E., 1976 The Hydrolysis of Cations New York Wiley 228 – 237.Google Scholar
Barnhisel, R. I., Bertsch, P. M. and Page, A. L., 1982 Aluminum Methods of Soil Analysis, Part 2 2nd Madison, Wisconsin American Society of Agronomy 275 – 297.Google Scholar
Chen, M. and Davidson, N., 1955 The kinetics of oxygenation of ferrous iron in phosphoric acid solution J. Amer. Chem. Soc. 77 793 – 798.Google Scholar
Fey, M. V. and Dixon, J. B., 1981 Synthesis and properties of poorly crystalline hydrated aluminous goethites Clays & Clay Minerals 29 91 – 100.CrossRefGoogle Scholar
Gerstl, Z. and Banin, A., 1980 Fe+2-Fe+3 transformations in clay and resin ion-exchange systems Clays & Clay Minerals 28 335 – 345.CrossRefGoogle Scholar
Millero, F. J., 1985 The effect of ionic interactions on the oxidation of metals in natural waters Geochim. Cosmo-chim. Acta 49 547 – 553.CrossRefGoogle Scholar
Misawa, T., Hashimoto, K. and Shimodarra, S., 1973 Formation of Fe(II)-Fe(III) intermediate green complex on oxidation of ferrous iron in neutral and slightly alkaline sulfate solutions J. Inorg. Nucl. Chem. 35 4167 – 4174.CrossRefGoogle Scholar
Schwertmann, U., Taylor, R. M., Dixon, J. B. and Weed, S. B., 1977 Iron oxides Minerals in Soil Environments Wisconsin Soil Science Society of America, Madison 145 – 180.Google Scholar
Sposito, G. and Mattigod, S. V., 1980 GEOCHEM. Dept. Soil and Environ. Sci. California Univ. California, Riverside.Google Scholar
Stucki, J. W. and Anderson, W. L., 1981 The quantitative assay of minerals for Fe+2 and Fe+3 using 1,10 phenanthroline Soil Sci. Soc. Amer. J. 45 663 637.Google Scholar
Stumm, W. and Morgan, J. J., 1981 Aquatic Chemistry New York Wiley 465 – 469.Google Scholar
Sugimoto, T. and Matijevic, E., 1980 Formation of uniform spherical magnetite particles by crystallization from ferrous hydroxide gels J. Colloid Interf. Sci. 74 227 – 243.CrossRefGoogle Scholar
Sung, W. and Morgan, J. J., 1980 Kinetics and product of ferrous iron oxygenation in aqueous solutions Environ. Sci. Tech. 14 561 – 568.CrossRefGoogle Scholar
Taylor, R. M., 1984 The rapid formation of crystalline double hydroxy salts and other compounds by controlled hydrolysis Clay Miner. 19 591 – 603.CrossRefGoogle Scholar
Taylor, R. M. and McKenzie, R. M., 1980 The influence of aluminum on iron oxides. VI. The formation of Fe(II)-Al(III) hydroxychlorides, sulfates, and carbonates as new members of the pyroaurite group and their significance in soils Clays & Clay Minerals 128 179 – 187.CrossRefGoogle Scholar
Taylor, R. M. and Schwertmann, U., 1974 Maghemite in soils and its origin. II. Maghemite synthesis at ambient temperature and pH 7 Clay Miner. 10 299 – 310.CrossRefGoogle Scholar
Taylor, R. M. and Schwertmann, U., 1978 The influence of aluminum on iron oxides. I. The influence of Al on Fe oxide formation from the Fe(II) system Clays & Clay Minerals 26 373 – 383.CrossRefGoogle Scholar
Tronc, E. and Jolivet, J.-P., 1984 Exchange and redox reactions at the interface of spinel-like iron oxide colloids in solution: Fe(II) absorption Absorp. Sci. Tech. 247 – 251.CrossRefGoogle Scholar