DESORPTION-KINETICS OF TRICHLOROETHYLENE FROM POWDERED SOILS

The short-term desorption of trichloroethylene (TCE) from standard powdered soils including limestone, flint clay, glass sand, plastic day, and soda feldspar was examined using an infra red absorption technique. The vapor-phase concentration of TCE as a function of desorption time is adequately described by the Langmuir kinetic mechanism. The desorption is rather rapid, with the vapor phase reaching a near steady-state value in several hours. The desorption rates are independent of the resident time for laboratory exposure of the soil to TCE in the range of 19-1350 h. The rate coefficients for desorption exhibit an Arrhenius temperature dependence with an activation energy of 0.37 +/- 0.03 eV and are linearly dependent on the surface area to volume ratio for particle sizes up to 10 mu m. The cross-section for optical absorption at lambda = 3.2 mu m was determined to be a = 3.34 +/- 0.01 x 10(-20) cm(2).