Vapor‐phase Diffusion of Benzene in Soil

The volatilization of benzene (C 6 H 6 ), a component of volatile emissions from landfills receiving certain industrial wastes, was characterized in the laboratory using a simulated landfill apparatus. The steady‐state vapor diffusion of C 6 H 6 in soil under isothermal conditions and negligible water flow was directly related to soil air‐filled porosity. The volatilization flux of C 6 H 6 through a soil cover was greatly reduced by increased soil bulk density and increased soil‐water content. The actual flux through the soil cover could be predicted from the soil porosity term, P 10/3 a P −2 T , where P a is the soil air‐filled porosity and P T is the total porosity. The diffusion coefficient in air for C 6 H 6 calculated from the experimental results was 8.91 × 10 −6 m 2 s −1 , at 20 °C, which agrees with other reported data.