Influence of mineral-bound humic substances on the sorption of hydrophobic organic compounds

Journal Article · Mon Oct 01 00:00:00 EDT 1990 · Environmental Science and Technology; (United States)

DOI:https://doi.org/10.1021/es00080a009· OSTI ID:5453303

Murphy, E M; Zachara, J M; Smith, S C ^[1]

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1. Pacific Northwest Laboratory, Richland, WA (USA)

The sorption of three hydrophobic organic compounds (HOC) was investigated on hematite and kaolinite that had been coated with natural humic substances over a mass percent carbon range of 0.01-0.5%. Increasing quantities of sorbed humic substances increased the sorption of HOC. Anthracene, the most hydrophobic HOC, showed the greatest sorption enhancement, while the most aromatic coating, peat humic acid, was the strongest sorbent. Depending on the type of humic acid coating and the mineral substrate, the experimental K{sub oc} values were either higher or lower than those predicted by the K{sub ow}. The sorptivity of a given humic acid for HOC was not the same on kaolinite and hematite, suggesting that the orientation and structure of the humic substance on the mineral may affect the surface area of the organic phase and the accessibility of hydrophobic domains that control HOC sorptivity. Sorption isotherms for HOC on the humic-coated mineral substrates were nonlinear, implying that the sorption phenomenon was adsorption onto rather than partitioning into the surface organic phase.

• DOE Contract Number: AC06-76RL01830
• OSTI ID: 5453303
• Journal Information: Environmental Science and Technology; (United States), Vol. 24:10; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
ORGANIC COMPOUNDS
SORPTION
ANTHRACENE
ENVIRONMENTAL TRANSPORT
HEMATITE
HUMIC ACIDS
KAOLINITE
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
AROMATICS
CHALCOGENIDES
CONDENSED AROMATICS
HYDROCARBONS
IRON COMPOUNDS
IRON ORES
IRON OXIDES
MASS TRANSFER
MINERALS
ORES
ORGANIC ACIDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
540220* - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)
580000 - Geosciences