Influence of gamma-radiation on the behavior of humic acids from peat and tropical soil

  • W. T. L. da Silva
  • S. C. da Silva
  • M. O. de Oliveira Rezende


HA samples obtained from sedimentary soil and peat in aqueous media were irradiated with γ-rays, in the dose range from 10 to 100 kGy, with the aim to study the chemical differences in the material before and after irradiation. The materials were analyzed by elemental analysis, UV/Vis spectroscopy (E4/E6 ratio), functional groups content, gel permeation chromatography (GPC) and IR spectroscopy. Gas chromatography was utilized to analyze the generated gases. Humic acids from peat and from soil are quite different. After irradiation an increasing in the average molecular weight was observed which depends on the material characteristics. There was observed also a release of CO2 upon irradiation. By infrared spectroscopy, with the help of computer simulations, the characteristic bands of ester C=O and C−O stretchings reinforces the contribution of carboxylic groups in the condensation process.


Ester Humic Acid Aqueous Medium Carboxylic Group Dose Range 
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  1. 1.
    F. J. Stevenson, Humus Chemistry, Willey, New York, 1982.Google Scholar
  2. 2.
    I. H. Suffet, P. Maccarthy (Eds), Aquatic Humic Substances: Influence on Fate and Treatment of Pollutants, ACS Books, Washington, 1989.Google Scholar
  3. 3.
    H. K. J. Powell, R. M. Town, Anal. Chim. Acta, 267 (1992) 47.CrossRefGoogle Scholar
  4. 4.
    R. L. Malcolm, Anal. Chim. Acta, 232 (1990) 19.CrossRefGoogle Scholar
  5. 5.
    G. Davies, E. A. Ghabbour, J. Jansen, J. Varnum, in: Polymers and Others Advanced Materials,P. N. Prasad, J. E. Mark, J. F. Tung (Eds), 3rd ed., Plenum, New York, 1995, p. 677.Google Scholar
  6. 6.
    P. J. Spedding, Fuel, 67 (1988) 883.CrossRefGoogle Scholar
  7. 7.
    A. Charlesby, in: Radiation Chemistry — Principles and Applications,Farhataziz, M. A. J. Rodgers (Eds), VCH Publishers, New York, 1987, p. 451.Google Scholar
  8. 8.
    F. M. Lanças, D. M. Pereira, J. Radioanal. Nucl. Chem., 172 (1993) 387.Google Scholar
  9. 9.
    N. Senesi, Y. Chen, M. Schnitzer, Fuel, 56 (1977) 171.CrossRefGoogle Scholar
  10. 10.
    G. V. Buxton, in: Radiation Chemistry — Principles and Applications,Farhataziz, M. A. J. Rodgers (Eds), VCH Publishers, New York, 1987, p. 321.Google Scholar
  11. 11.
    W. T. L. Silva, E. M. Vieira, V. M. Cruzes, M. O. O. Rezende, Química Nova, 18 (1995) 541.Google Scholar
  12. 12.
    M. Schnitzer, in: Soil Organic Matter,M.Schnitzer, S. V. Khan (Eds), Elsevier, Amsterdam, 1978, p. 3.Google Scholar
  13. 13.
    M. Schnitzer, U. C. Gupta, Soil. Sci. Soc. Proc., 274 (1965) 274.CrossRefGoogle Scholar
  14. 14.
    V. M. Cruzes, S. C. Silva, M. O. O. Rezende, FTIR study of humic acids, to be published.Google Scholar
  15. 15.
    HyperChem 4.5, Molecular Visualization and Simulation, Hypercube, 1994.Google Scholar
  16. 16.
    C. J. Pouchert, The Aldrich Library of FT-IR Spectra, Vol 3 (Vapour Phase), 1st ed., Aldrich, 1989.Google Scholar

Copyright information

© Akadémiai Kiadó 1997

Authors and Affiliations

  • W. T. L. da Silva
    • 1
  • S. C. da Silva
    • 1
  • M. O. de Oliveira Rezende
    • 1
  1. 1.Instituto de Química de São CarlosUniversidade de São PauloSão CarlosBrasil

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