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Reevaluation of Partitioning as a Mechanism of Nonionic Chemicals Adsorption in Soils
Author(s) -
Mingelgrin U.,
Gerstl Z.
Publication year - 1983
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1983.00472425001200010001x
Subject(s) - adsorption , partition coefficient , chemistry , partition (number theory) , aqueous solution , aqueous two phase system , soil water , solubility , phase (matter) , organic chemistry , computational chemistry , soil science , mathematics , environmental science , combinatorics
A critical evaluation of recent suggestions that the adsorption of nonionic organic compounds by soils can be well‐correlated with the partition of the compounds between an aqueous and a nonpolar phase (usually 1‐octanol), or with water solubility is presented. The physical basis proposed for these assumptions is that adsorption of nonionic organic compounds on soil organic matter is a “partition” process between the aqueous phase and a hydrophobic surface phase. The evidence presented in the literature for the dominance of a partition mechanism is insufficient to prove its general applicability. For example, systems in which a distinct hydrophobic phase at the solid surface does not exist are shown to exhibit the uptake behavior presumed to characterize partition. Theoretically, as well as practically, surface uptake cannot be simply defined as “adsorption” or “partition”, but rather there is a continuum of possible interactions starting with fixed site adsorption and ending with true partition between three‐dimensional phases.