Abstract
Humic acid sample was separated from the bottom sediments of Lake Quarun, in Egypt. It was purified and characterized by elemental analysis, potentiometric titration, IR, UV-visible and 13C NMR spectroscopies. The product of humic acid was very low (0.009%), gray in color and has low carboxylate capacity (2.4 meq/g). The first derivative of the titration curve indicated one maximum only, which implies one kind of carboxylate groups. The binding constant of 234Th with Lake Quarun humic acid was determined by solvent extraction. Only one parameter, β 1, was required to fit the binding as a function of carboxylate concentration: the Th4+ bound to the carboxylate sites in the gray humic acid forming 1:1 complex only. The binding constant increased with the degree of ionization and with the pKa of the humic acid.
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References
H. Baker, F. Khalili, Anal. Chim. Acta, 542 (2005) 240.
G. R. Aiken, D. M. McKnight, R. L. Wershaw, P. MacCarthy, Humic Substances in Soil, Sediment and Water, John Wiley & Sons, New York, 1985, p. 14.
F. J. Stevenson, Humus Chemistry (Genesis, Composition, Reactions), 2nd ed., John Wiley and Sons, New York, 1994.
P. Dubach, N. C. Mehta, Soils Fertilizers, 26 (1963) 239.
M. H. B. Hayes, R. S. Swift, The Chemistry of Soil Organic Colloids, in: The Chemistry of Soil Constituents, D. J. Greenland, M. H. B. Hayes (Eds), Wiley-Interscience, New York, 1978, p. 179.
M. Schnitzer, S. U. Khan, Soil Organic Matter, Elsevier, New York, 1978, p. 319.
W. Hummel, M. A. Glaus, L. R. Van Loon, Radiochim. Acta, 84 (1999) 111.
A. A. Helal, H. F. Aly, D. M. Imam, S. M. Khalifa, J. Radioanal. Nucl. Chem., 227 (1998) 49.
J. P. Pinheiro, A. M. Mota, M. L. Simoes Goncalves, J. Anal. Chim. Acta, 284 (1994) 525.
L. Hargitai, J. Sci. Total Environ., 81/82 (1989) 643.
R. A. Torres, G. R. Choppin, J. Radiochim. Acta, 35 (1984) 143.
P. M. Shanbhag, G. R. Choppin, J. Inorg. Nucl. Chem., 43 (1981) 3369.
A. A. Helal, D. M. Imam, H. F. Aly, J. Radioanal. Nucl. Chem., 237 (1998) 7.
A. A. Helal, Aly A. Helal, N. Z. Selim, S. M. Khalifa, J. Radioanal. Nucl. Chem., 267 (2006) 369.
A. A. Helal, Aly A. Helal, N. Z. Selim, S. M. Khalifa, J. Radioanal. Nucl. Chem., 267 (2006) 363.
D. F. Peppard, G. W. Mason, J. L. Maier, W. J. Driscoll, J. Inorg. Nucl. Chem., 4 (1957) 334.
A. A. Helal, D. M. Imam, H. F. Aly, Egypt. J. Anal. Chem., 5 (1996) 79.
M. S. Caceci, G. R. Choppin, Radiochim. Acta, 33 (1983) 113.
K. L. Nash, G. R. Choppin, J. Inorg. Nucl. Chem., 42 (1980) 1045.
N. A. Tolba, Proc. 1st Symp., Lake Quarun, Fayoum 8 April, 1995, p. 37.
A. A. Helal, D. M. Imam, S. M. Khalifa, H. F. Aly, J. Radioanal. Nucl. Chem., 232 (1998) 159.
A. A. Helal, D. M. Imam, S. M. Khalifa, H. F. Aly, J. Radiochem., 48 (2006) 419.
C. Steinberg, U. Muenster, Geochemistry and Ecological Role of Humic Substances in Lake Water, in: Humic Substances in Soil, Sediment and Water, John Wiley & Sons, New York, 1985, p. 166.
R. Ishiwatari, J. Soil Sci., 107 (1969) 53.
F. J. Stevenson, K. M. Goh, J. Geochim. Acta, 35 (1971) 417.
M. Schnitzer, S. U. Khan, Humic Substances in the Environment, Marcel Dekker, New York, 1972, p. 59.
R. A. Torres, Ph. D. Thesis, Florida State University, USA, 1982.
A. A. Helal, G. A. Morad, S. M. Khalifa, J. Radiochem., 47 (2005) 520.
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Helal, A.A. Binding constant of thorium with gray humic acid. J Radioanal Nucl Chem 274, 575–580 (2007). https://doi.org/10.1007/s10967-006-6920-2
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DOI: https://doi.org/10.1007/s10967-006-6920-2