U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings
of the Technical Meeting, Colorado Springs, Colorado, September 20-24, 1993,
Water-Resources Investigations Report 94-4015
Modeling Breakthrough of Nitrogen Heterocyclic Compounds in
Laboratory Columns Containing Creosote-Contaminated Aquifer Material
by
Ean Warren (U.S. Geological Survey, Menlo Park, Calif.) and E.
Michael Godsy (U.S. Geological Survey, Menlo Park, Calif.)
Abstract
Laboratory-column breakthrough curves for the nitrogen-containing heterocyclic
compounds found in the water soluble fraction of creosote were modeled and
compared assuming local equilibrium and nonequilibrium conditions. The aquifer
material consisted of a low organic-carbon-content (0.024 percent organic
carbon), low ion-exchange-capacity (2 meq/100 g) clayey sand. Retardation
factors and partition coefficients for quinoline, 2(1H)-quinolinone, carbazole,
and acridine, derived from breakthrough curves, were contrasted with those
obtained from batch experiments. Retardation factors for quinoline and 2(1H)-quinolinone
were comparable to each other, although those for carbazole and acridine
were quite different despite similar chemical structures and octanol-water
partition coefficients. Transport of quinoline, 2(1H)-quinolinone, and acridine
is governed by organic and ionic interactions; however, transport of carbazole
is controlled by organic interactions alone. In addition, although the local
equilibrium assumption can be used to describe quinoline and 2(1H)-quinolinone
breakthrough curves, carbazole and acridine breakthrough curves require
nonequilibrium kinetics.
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