NMR Imaging of nonaqueous‐phase liquid dissolution in a porous medium

Abstract

AbstractIt is demonstrated how NMR imaging can be used noninvasively to quantify the volume of nonaqueous phase liquid (NAPL) present in an otherwise water‐saturated porous medium. Data were recorded during the operation of a pump and treat (PT) remediation scheme on a bed of water‐saturated sand contained within a vertical column. The model contaminant used was n‐hexanol, and three different aqueous flow rates were employed. These data were then critically compared with the predictions of three models currently used to describe the dissolution of NAPL during a PT scheme: the linear mass‐transfer model, the pore‐diffusion model, and the shrinking‐core model. The pore‐diffusion model gave best agreement with the experimental data. However, none of the models predicted the observed dependence of mass transfer on Darcy velocity.