A higher mass flux from the effected DNAPL migration and distribution patterns by brine flow in saturated porous media

Abstract

This study investigated the influence of groundwater salinity on DNAPL migration and distribution in saturated physically homogeneous and heterogeneous porous media. Interfacial tension (IFT) of PCE/aqueous phase containing NaCl and contact angles through the aqueous phase measured results showed that the contact angle decreased and IFT increased with NaCl concentration, leading to the fact that the wettability of quartz sand can be changed from water-wet to strong water-wet. Three sets of two-dimensional (2-D) sandbox experiments conducted with different salinity showed DNAPL migrated faster in the vertical direction in salinity, yielding decreased residual DNAPL entrapped in the migration path. In addition, the salinity-induced strong water-wet media promoted DNAPL trapping at relatively lower saturation both in the coarse or medium sand, and the volume of PCE entrapped as ganglia increased in the salinity cells. The salinity enhanced the dissolution of PCE from the source zone due to the PCE zone architecture change.