The transport of silica powders and lead ions under unsteady flow and variable injection concentrations

Abstract

The transport of silica powders (SPs), which are a type of suspended particles, and lead ions (a heavy metal species) in saturated porous media under unsteady flow and variable lead ion injection concentrations was investigated. During the transport of lead ions alone, the lead ion concentration in the effluent was almost constant during the entire penetration process; i.e., the transport of lead ions was not affected by changes in the seepage velocity. After coupling with SPs, the penetration process of lead ions varied significantly with the seepage velocity. At a low lead ion injection concentration, the presence of SPs significantly promoted the transport of lead ions. However, at a high lead ion concentration, the presence of SPs tended to inhibit the transport of lead ions. The present study aims to broaden the potential prospects for the application of SP-like particulate materials in the treatment of pollutants in permeable soil.