In situ decontamination of soil containing 2,3,7,8-tetrachlorodibenzo-p-dioxin: Physical parameter analysis and mathematical model

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5121200

Dougherty, E J

The extremely low water solubility and vapor pressure of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) cause it to be a very persistent soil contaminant. A relatively low-cost cleanup technique has been investigated. This involves adding a mixture of organic solvents to contaminated soil, then allowing time for transport and photodegradation of the TCDD at the surface of the soil. In the development of the optimum conditions for this process, several studies of fundamental TCDD properties have been undertaken. TCDD transport may occur when an organic phase provides a transportation medium, but measurements of physical constants necessary to describe this migration are not available in the literature. The rate constants for adsorption and desorption of TCDD to Norfolk loamy sand in four organic liquids have been determined from a kinetic analysis of new experimental data. In order to describe TCDD movement in an organic liquid in soil, diffusivity measurements were needed. These were conducted using a Taylor-Aris dispersion technique, and values for the diffusivities were found. Experiments to quantify the diffusive transport of TCDD in soil containing various levels of organic solvents were also designed and modeled using the results of the previous studies. Finally, the kinetics of TCDD photodegradation were investigated. These data were used in extending the transport analysis to describe the movement of TCDD in soil with organics in long-term studies in sunlight, where the contaminant can undergo photodegradation. The model describes the transport, accumulation, and degradation of TCDD, and could be used to simulate various decontamination conditions without the necessity of carrying out experiments.

• Research Organization: North Carolina State Univ., Raleigh, NC (United States)
• OSTI ID: 5121200
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
ADSORPTION
CLEANING
DECONTAMINATION
DESORPTION
DIOXIN
ENVIRONMENTAL TRANSPORT
HETEROCYCLIC COMPOUNDS
IN-SITU PROCESSING
LAND POLLUTION
MASS TRANSFER
MATHEMATICAL MODELS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC SOLVENTS
PHYSICAL PROPERTIES
POLLUTION
PROCESSING
REMEDIAL ACTION
SOILS
SOLUBILITY
SOLVENTS
SORPTION
THERMODYNAMIC PROPERTIES
VAPOR PRESSURE