Influence of nonlinear sorption kinetics on the slow-desorbing organic contaminant fraction in soil

Journal Article · Sat May 01 04:00:00 EDT 1999 · Environmental Science and Technology

DOI:https://doi.org/10.1021/es980233e· OSTI ID:354343

Schlebaum, W; Schraa, G; Van Riemsdijk, W H ^[1]

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1. Wageningen Agricultural Univ. (Netherlands)

Release rates of hydrophobic organic compounds (HOCs) from the soil matrix influence the availability of HOCs in soils or sediments for microbial degradation or removal by physical means (e.g., soil washing or soil venting). In this study it was shown that the initial contaminant concentration influences the desorption rate. This was attributed to the presence of a limited number of high affinity sites that cause nonlinear sorption behavior. The experimental results could be described with a kinetic model composed of two separate compartments. One compartment was described with a Freundlich isotherm and corresponding kinetics and was assumed to represent sorption to high affinity sites. The second compartment was described with a linear sorption isotherm and first-order kinetics. The model was used to simulate the influence of purging strategies on removal of QCB. The simulations showed that after removal of a fast-desorbing fraction, the slow-desorbing fraction could be efficiently removed at very low purging rates. Intermittent purging reduced the total purging time but the simulations showed large fluctuations in the aqueous pentachlorobenzene concentration. For each subsequent purging interval, the purging efficiency decreased due to the nonlinear desorption kinetics of the slow-desorbing fraction of pentachlorobenzene.

• OSTI ID: 354343
• Journal Information: Environmental Science and Technology, Journal Name: Environmental Science and Technology Journal Issue: 9 Vol. 33; ISSN ESTHAG; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CHLORINATED AROMATIC HYDROCARBONS
DESORPTION
MATHEMATICAL MODELS
REMEDIAL ACTION
SOIL CHEMISTRY
SOILS