Geosorbent organic matter and its relationship to the binding and sequestration of organic contaminants

Walter J. Weber, Weilin Huang, Eugene J. LeBoeuf

Research output: Contribution to journalConference article

61 Scopus citations


A dual reactive domain model (DRDM) for sorption of hydrophobic organic contaminants by soils, sediments, and other geosorbents is described. The model is predicated on the hypothesis that heterogeneous natural sorbent organic matter (SOM) comprises two principal chemostructurally different domains; a highly amorphous domain and a relatively condensed domain. The existence of two chemically and phenomenologically different SOM domains is evidenced by observations of a glass transition for a soil-derived humic acid. Extensive examinations of phenanthrene sorption and desorption for a broad range of soils, sediments, shales, and kerogens reveal that sorption by condensed SOM matrices is nonlinear and hysteretic while sorption by amorphous SOM domains is linear and completely reversible. Semi-quantitative correlations between SOM oxygen/carbon (O/C) atomic ratios and isotherm linearity (n), single-point KOC values, and degrees of sorption-desorption hysteresis indicate that the geochemistry of SOM determines binding and sequestration of organic contaminants by soils and sediments. The model reconciles observations of, and provides predictability for, various complex sorption phenomena associated with soils and sediments.

Original languageEnglish (US)
Pages (from-to)167-179
Number of pages13
JournalColloids and Surfaces A: Physicochemical and Engineering Aspects
Issue number1-2
Publication statusPublished - Jun 15 1999
Externally publishedYes
EventProceedings of the 1997 International Conference on Interfaces against Pollution - Wageningen, Neth
Duration: Aug 10 1997Aug 13 1997


All Science Journal Classification (ASJC) codes

  • Surfaces and Interfaces
  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry


  • Contaminant sequestration
  • Desorption
  • Geosorbent organic matter
  • Humic acid glass transitions
  • Hydrophobic organic contaminants
  • Phenanthrene
  • Sorption

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