Wednesday, June 11, 2008
McKinley/Hayes (Hyatt Regency Columbus)

Measurements of Effective Vapor Diffusion Coefficients in Porous Substrates

Hongyang Li, Ali R. Zand, Jennifer Meyers, Elizabeth Bowden, Lars Beholz, Bojan Markicevic, Yuri Sikorski, Matthew S. Sanders, and Homayun Navaz. Kettering University, Flint, MI

Release of toxic chemicals, such as pesticides, chemical warfare agents, etc.; into soil, subsurface, concrete, brick and asphalt poses a great threat to the biosphere environment. A determination of the vapor-phase effective diffusion coefficient is important for predicting the fate of chemicals deposited onto porous substrates and carrying out the remediation work. In the present analysis the mass flux through the medium as well as the vapor concentration along porous substrate bed were measured. For the measurement of mass flux, an analytical balance was used and changes in mass were recorded in time, while the concentration profile along the porous substrate bed was measured in-situ using Single-Drop Vapor Phase MicroExtraction (SDVPME) method via a simple experimental apparatus. The measurements were taken once a linear (steady-state) concentration profile along the column was established.