The dissolution, diffusion, and volatilization of a free-phase benzene glob in the presence of air sparging were measured in laboratory-scale air sparging reactors and modeled using a dissolution-diffusion-volatilization (DDV) model. The estimated dissolution rate coefficients (K-f) from the DDV model ranged from 0.0050 to 0.017 min/min while the estimated volatilization rate coefficients (K-L) ranged from 0.012 cm/min to 0.029 mm/min. The DDV model fitted well the aqueous phase migration of benzene for air channels spaced at 45 and 60 mm. For air channels spaced at 30 mm, the model fitted the aqueous migration at most locations except above the benzene glob where the model underestimated the experimentally determined concentrations. However, the mass removed using the gas phase concentrations as predicted by the model were 65% of the actual mass removed. These observations suggest that other mass transport mechanisms may influence benzene mass removal, especially when the air channels are close to the benzene glob.
