Comparative studies of the reduction behavior of chromium(VI) by humic substances and their precursors

Ken Nakayasu, Masami Fukushima, Keiko Sasaki, Shunitz Tanaka, Hiroshi Nakamura

Research output: Contribution to journalArticle

71 Citations (Scopus)

Abstract

Hexavalent chromium (Cr[VI]) is reduced by dissolved organic carbons (DOCs) such as humic substances, tannic acid (TA), and gallic acid (GA). The kinetic constants and the resulting chemical species after the reduction were compared with each other. The kinetic constants for GA and TA, which are model precursors of humic substances, were two to three orders of magnitude larger than those for the humic substances when these kinetic constants were expressed as a function of the molar concentration of the reductive functional group (F(red)) in various DOCs. After the reduction of Cr(VI), the percentages of the species complexed with GA and TA were higher than those with the humic substances. This appears to be due to the formation of high molecular weight compounds by polymerization during the reduction of Cr(VI) and complexation of Cr(III) with the polymerized compounds. The UV-vis spectrophotometric data and gel permeation chromatography support this view.

Original languageEnglish
Pages (from-to)1085-1090
Number of pages6
JournalEnvironmental Toxicology and Chemistry
Volume18
Issue number6
DOIs
Publication statusPublished - May 27 1999

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Humic Substances
humic substance
Gallic Acid
chromium
Tannins
comparative study
acid
Organic carbon
Kinetics
kinetics
Carbon
dissolved organic carbon
Gel permeation chromatography
Complexation
Functional groups
Polymerization
Molecular weight
Gel Chromatography
complexation
polymerization

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Health, Toxicology and Mutagenesis

Cite this

Comparative studies of the reduction behavior of chromium(VI) by humic substances and their precursors. / Nakayasu, Ken; Fukushima, Masami; Sasaki, Keiko; Tanaka, Shunitz; Nakamura, Hiroshi.

In: Environmental Toxicology and Chemistry, Vol. 18, No. 6, 27.05.1999, p. 1085-1090.

Research output: Contribution to journalArticle

Nakayasu, Ken ; Fukushima, Masami ; Sasaki, Keiko ; Tanaka, Shunitz ; Nakamura, Hiroshi. / Comparative studies of the reduction behavior of chromium(VI) by humic substances and their precursors. In: Environmental Toxicology and Chemistry. 1999 ; Vol. 18, No. 6. pp. 1085-1090.
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