Reaction of aquatic humic substances with aluminium

a Al-27 NMR study

Russell Francis Howe, X Q Lu, J Hook, W D Johnson

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Al-27 NMR spectroscopy showed that humic substances from swamp water can complex aluminium(III) ion. At the relatively low concentration of 0.002 M humic substances, the Al-27 NMR spectrum shows only one peak, with a chemical shift at 6.5 ppm. As the concentrations of the humic substances increased, the Al-27 NMR spectra showed three peaks with chemical shifts at 6.5, 12.4, and 16.5 ppm, respectively, indicating that there are at least three complexing species formed in the solutions of humic substance at the different concentrations. Humic substances from surface soil, pear and brown coal also formed complexes with aluminium(III). Investigation of the reaction of organic acids with aluminium(III) ion indicated that the chemical shifts of aluminium complexes observed in solutions of swamp humic substances are similar to those in oxalic acid solutions, suggesting that the three peaks represent aluminium complexes formed in the humic substances with one, two and three oxalic acid-like groups. Significant complexation of aluminium occurs at low pH, suggesting that humic substances play an important role in the transport of this metal in acidic environments.

Original languageEnglish
Pages (from-to)377-383
Number of pages7
JournalNew Zealand Journal of Marine and Freshwater Research
Volume48
Issue number5
Publication statusPublished - 1997

Keywords

  • nuclear magnetic-resonance
  • acidic waters
  • fulvic-acid
  • speciation
  • aluminium(III)
  • complexes
  • fluoride
  • binding

Cite this

Reaction of aquatic humic substances with aluminium : a Al-27 NMR study. / Howe, Russell Francis; Lu, X Q ; Hook, J ; Johnson, W D .

In: New Zealand Journal of Marine and Freshwater Research, Vol. 48, No. 5, 1997, p. 377-383.

Research output: Contribution to journalArticle

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abstract = "Al-27 NMR spectroscopy showed that humic substances from swamp water can complex aluminium(III) ion. At the relatively low concentration of 0.002 M humic substances, the Al-27 NMR spectrum shows only one peak, with a chemical shift at 6.5 ppm. As the concentrations of the humic substances increased, the Al-27 NMR spectra showed three peaks with chemical shifts at 6.5, 12.4, and 16.5 ppm, respectively, indicating that there are at least three complexing species formed in the solutions of humic substance at the different concentrations. Humic substances from surface soil, pear and brown coal also formed complexes with aluminium(III). Investigation of the reaction of organic acids with aluminium(III) ion indicated that the chemical shifts of aluminium complexes observed in solutions of swamp humic substances are similar to those in oxalic acid solutions, suggesting that the three peaks represent aluminium complexes formed in the humic substances with one, two and three oxalic acid-like groups. Significant complexation of aluminium occurs at low pH, suggesting that humic substances play an important role in the transport of this metal in acidic environments.",
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T2 - a Al-27 NMR study

AU - Howe, Russell Francis

AU - Lu, X Q

AU - Hook, J

AU - Johnson, W D

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Y1 - 1997

N2 - Al-27 NMR spectroscopy showed that humic substances from swamp water can complex aluminium(III) ion. At the relatively low concentration of 0.002 M humic substances, the Al-27 NMR spectrum shows only one peak, with a chemical shift at 6.5 ppm. As the concentrations of the humic substances increased, the Al-27 NMR spectra showed three peaks with chemical shifts at 6.5, 12.4, and 16.5 ppm, respectively, indicating that there are at least three complexing species formed in the solutions of humic substance at the different concentrations. Humic substances from surface soil, pear and brown coal also formed complexes with aluminium(III). Investigation of the reaction of organic acids with aluminium(III) ion indicated that the chemical shifts of aluminium complexes observed in solutions of swamp humic substances are similar to those in oxalic acid solutions, suggesting that the three peaks represent aluminium complexes formed in the humic substances with one, two and three oxalic acid-like groups. Significant complexation of aluminium occurs at low pH, suggesting that humic substances play an important role in the transport of this metal in acidic environments.

AB - Al-27 NMR spectroscopy showed that humic substances from swamp water can complex aluminium(III) ion. At the relatively low concentration of 0.002 M humic substances, the Al-27 NMR spectrum shows only one peak, with a chemical shift at 6.5 ppm. As the concentrations of the humic substances increased, the Al-27 NMR spectra showed three peaks with chemical shifts at 6.5, 12.4, and 16.5 ppm, respectively, indicating that there are at least three complexing species formed in the solutions of humic substance at the different concentrations. Humic substances from surface soil, pear and brown coal also formed complexes with aluminium(III). Investigation of the reaction of organic acids with aluminium(III) ion indicated that the chemical shifts of aluminium complexes observed in solutions of swamp humic substances are similar to those in oxalic acid solutions, suggesting that the three peaks represent aluminium complexes formed in the humic substances with one, two and three oxalic acid-like groups. Significant complexation of aluminium occurs at low pH, suggesting that humic substances play an important role in the transport of this metal in acidic environments.

KW - nuclear magnetic-resonance

KW - acidic waters

KW - fulvic-acid

KW - speciation

KW - aluminium(III)

KW - complexes

KW - fluoride

KW - binding

M3 - Article

VL - 48

SP - 377

EP - 383

JO - New Zealand Journal of Marine and Freshwater Research

JF - New Zealand Journal of Marine and Freshwater Research

SN - 0028-8330

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ER -