Journal Article

Comparison of Naphthalene Diffusion and Non-equilibrium Adsorption-Desorption Experiments

Gamst, Jesper, Olesen, Torben, Scow, Kate, Komatsu, Toshiko, Moldrup, Per, Rolston, Dennis E

2003

Overview

Diffusion of hydrophobic organic compounds (HOCs) may be exploited to control spreading of these contaminants in the vadose zone. Effective (net) diffusion of naphthalene was studied in five unsaturated soil types using several experimental approaches on repacked soil columns. Soil type did not appear to affect gas diffusion, but it did affect naphthalene sorption behavior, with nonlinear and nonsingularity effects being observed. Gas diffusion was the primary naphthalene transport mechanism in half-cell experiments; effective diffusion coefficients were calculated from various concentration profiles. These and other findings suggest that the sorption nonlinearity was a good indicator of the degree of nonsingularity in both HOC adsorption-desorption and effective diffusion. Batch and half-cell experiments provided useful information for predicting HOC diffusive transport.