Equilibrium and Coagulation Characteristics of Humic Iron Complex in Estuaries

• FUJII Manabu

  Department of Civil Enginee ring, Graduate School of Engineering, Tohoku University

• SASAKI Akira

  Department of Civil Enginee ring, Graduate School of Engineering, Tohoku University

• WATANABE Toru

  Department of Civil Enginee ring, Graduate School of Engineering, Tohoku University

• OMURA Tatsuo

  Department of Civil Enginee ring, Graduate School of Engineering, Tohoku University

Bibliographic Information

Other Title

• 河口・沿岸域におけるフミン鉄の錯平衡と凝集特性

Abstract

Humic iron complex is one of the most essential minerals for the growth of aquatic organisms in estuaries. However, the behavior of humic iron complex has not been known so well in estuaries where salinity widely changes. In this study, the effect of salinity on the behavior of humic iron complex was investigated with the Dando humic and fulvic acids. The increase of salinity, especially divalent cations such as magnesium and calcium ions, enhanced the coagulation of humic substances (HS). When the salt concentration increased from 0 to 30g/L, 81% of dissolved humic acid (HA) and 18% of dissolvedfulvic acid (FA) transformed to the particulate (>0.45μm) due to the coagulation. Gel chromatography analysis with UV spectrometer (254nm) revealed that high molecular weight and hydrophobic fractions of humic substances were important factors relevant to the coagulation. The increase of salinity also enhanced the dissociation of iron from HA and FA. With the increase of salt concentration from 0 to 30g/L, 98% and 88% of iron dissociated from HA and FA, respectively. It was expected that amino and sulfo groups on the surface of HA and FA which possess a high affinity with iron contributed to the subsistence of dissolved iron in estuaries.

Journal

• ENVIRONMENTAL ENGINEERING RESEARCH

  ENVIRONMENTAL ENGINEERING RESEARCH 41 389-400, 2004

  Japan Society of Civil Engineers

Keywords

• Humic and fulvic acids
• Iron
• Estuary
• Coagulation
• Equilibrium

Details

• CRID: 1390001204112780416
• NII Article ID: 130003949389
• DOI: 10.11532/proes1992.41.389
• ISSN: 1884829X
• ISSN: 13415115
• Text Lang: ja
• Data Source:
  • JaLC
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed