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The Sorption of Nonionic Organic Solutes to Humic Acid‐Mineral Complexes: Effect of Cosolutes
Author(s) -
Onken B. M.,
Traina S. J.
Publication year - 1997
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/jeq1997.00472425002600010020x
Subject(s) - sorption , chemistry , adsorption , humic acid , pyrene , anthracene , environmental chemistry , naphthalene , phenanthrene , organic matter , organic chemistry , fertilizer
In binary isotherms, pyrene and naphthalene sorption were enhanced by the presence of anthracene as a cosorbate. Sorption enhancement was observed at low fractional organic carbon content ( f oc ) (<3 × 10 −5 ) and diminished f oc increased. The addition of cosolutes to low f oc systems (<3 × 10 −5 ) appeared to aid the transition from adsorption/condensation type surface interactions to an interaction more like partitioning. It is postulated that observed sorption enhancement in higher f oc systems (= 3 × 10 −5 ) was due to an increase in effective f oc resulting from cosolute sorption. The presence of a cosolute did not affect systems where partitioning was already the primary process. If partitioning was not occurring, the addition of a cosolute reduced the surface excess of the solute by competing for adsorption sites. This competition occurred until surface organic C increased to a sufficient concentration to promote partitioning. This research indicates that the use of K oc values derived from K ow data in low f oc systems significantly underestimate the interactions of nonionic organic solutes with low organic C surfaces.