Transport and sorption of volatile organic compounds and water vapor within dry soil grains

Journal Article · Tue Feb 01 04:00:00 EST 1994 · Environmental Science and Technology; (United States)

DOI:https://doi.org/10.1021/es00051a020· OSTI ID:5138944

Lin, T F; Nazaroff, W W ^[1]; Little, J C ^[2]

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1. Univ. of California, Berkeley, CA (United States) Lawrence Berkeley Lab., CA (United States)
2. Univ. of California, Berkeley, CA (United States)

Mechanisms governing the rates of adsorption and desorption of benzene, trichloroethylene, and water vapor by dry soil grains are investigated. For three different test soils, determinations are made of organic carbon content, specific surface area, grain density, grain porosity, and pore size distribution. Experimental measurements of the rates of adsorption and desorption show that periods of hours are required to achieve equilibrium. In addition, adsorption is observed to be much faster than desorption. A porous sphere model accounting for internal diffusion in spherical grains coupled with a nonlinear Freundlich isotherm is used to interpret the sorption rate data. The model follows both adsorption and desorption trends reasonably well using a single fitted parameter, the effective diffusivity. The model also provides good resolution of the substantial asymmetry in the rates of uptake and release. In a refinement, a parallel pore model is used to account more fully for effects of the experimentally measured pore size distribution. 37 refs., 9 figs., 3 tabs.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5138944
• Journal Information: Environmental Science and Technology; (United States), Journal Name: Environmental Science and Technology; (United States) Vol. 28:2; ISSN ESTHAG; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
54 ENVIRONMENTAL SCIENCES
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
ADSORPTION ISOTHERMS
AROMATICS
BENZENE
CHLORINATED ALIPHATIC HYDROCARBONS
DESORPTION
DIFFUSION
EQUILIBRIUM
FLUIDS
GASES
GRAIN DENSITY
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROCARBONS
ISOTHERMS
LAND POLLUTION
MATHEMATICAL MODELS
MATTER
MICROSTRUCTURE
MONITORING
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
POLLUTION
POROSITY
SOILS
SORPTION
SURFACE AREA
SURFACE PROPERTIES
VAPORS
VOLATILE MATTER
WATER VAPOR