Analytical Solution of the One-Dimensional Transport of Ionic Contaminants in Porous Media with Time-Varying Velocity

The one-dimensional convection–dispersion equation has been widely used to describe the migration process of contaminant leachate through barriers. However, most existing solutions are limited simple conditions. In this study, a model with time-dependent velocity was established while considering change in permeability coefficient. analytical solution obtained by using integral transformation method. Based on model, three special conditions were assumed for comparison. results showed that concentration levels pollutants inside barrier would significantly increase flow velocity, and pollutant concentrations be increased four times compared normal when rate two times. transports heavy metal ions variable velocities soil–bentonite soil–attapulgite barriers predicted under field breakthrough time reduced as much engineering practice, barrier’s service performance can improved controlling temperature seepage improving chemical compatibility materials.