Sorption of 2,3,7,8-tetrachlorodibenzo-p-dioxin to soils from water/methanol mixtures
Sorption of /sup 14/C-labeled 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to soils from water/methanol mixtures has been evaluated by batch shake testing. Uncontaminated soils from Times Beach, MO, were used in these experiments and ranged in fraction organic carbon (f/sub oc/) from 0.0066 to 0.077. Volume fraction methanol in the liquid phase (f/sub s/) was varied between 0.25 and 1.0. Sorption kinetics were influenced by soil type and f/sub s/; at f/sub s/ of 0.5, sorption equilibrium for low-f/sub oc/ soils was achieved within 1 day, while sorption to the high-f/sub oc/ soil required as long as 30 days to reach equilibrium. For f/sub s/ of 1.0 and the high-f/sub oc/ soil, sorption equilibrium was attained in about 10 days. Sorption isotherms were linear, and when sorption partition coefficients (K/sub D/, mL/g) were converted to K/sub m/ (mol/g), these latter values were log-linearly related to f/sub s/. K/sub m/ values for two soils, when normalized on f/sub oc/, gave values of K/sub m,oc/ that collapsed onto a single line having the equation determined by linear regression analysis: log K/sub m,oc/ = -4.97f/sub s/ + 5.30 with r/sup 2/ = 0.98 and s = 0.20. log K/sub oc/, the logarithm of the aqueous-phase partition coefficient normalized on f/sub oc/, for TCDD extrapolated from this relationship is 6.6 +/- 0.7. The slope of the log-linear relationship is related to the effect of f/sub s/ on TCDD solubility and on TCDD-soil and solvent-soil interactions.
- Research Organization:
- Univ. of Maryland, College Park (USA)
- OSTI ID:
- 6870618
- Journal Information:
- Environ. Sci. Technol.; (United States), Vol. 22:7
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DIOXIN
SORPTION
SOILS
CONTAMINATION
CARBON 14 COMPOUNDS
METHANOL
MISSOURI
MIXTURES
SOIL CHEMISTRY
TRACER TECHNIQUES
ALCOHOLS
CHEMISTRY
DISPERSIONS
FEDERAL REGION VII
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
NORTH AMERICA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
USA
510200* - Environment
Terrestrial- Chemicals Monitoring & Transport- (-1989)
510101 - Environment
Terrestrial- Basic Studies- Radiometric Techniques- (-1989)