Adsorption of VOC vapors at the air-water interface in unsaturated media

• Main Author: Enright, Bryn Alison.
• Other Authors: Conklin, Martha H.
• Language: en
• Published: The University of Arizona. 1998
• Online Access: http://hdl.handle.net/10150/191340

The sorption of organic vapors to the air-water interface was studied using a wetted gas chromatograph column packed with a diatomaceous earth based media. Data were collected from 22 experiments on heptane, benzene, trichloroethene (TCE), perchioroethene (PCE), p-xylene and toluene at different moisture contents (lO%-30%). Sorption isotherms were constructed and air-water partitioning coefficients calculated. Results showed that sorption of the acyclics was primarily at the air-water interface and the aromatics were controlled by both adsorption at the interface and dissolution. These results also showed that solubility is not always a good indicator of the magnitude of the interface-air distribution coefficient as previous research suggests. The implication of this study is that adsorption to the air-water interface can be significant and must be quantified to accurately predict transport through the vadose zone.