Transport and retention of engineered nanoporous particles in porous media: Effects of concentration and flow dynamics

Abstract

Engineered nanoporous particles are an important class of nano-structured materials that can be functionalized in their internal surfaces for various applications including groundwater contaminant sequestration. This paper reported a study of transport and retention of engineered nanoporous silicate particles (ENSPs) that are designed for treatment and remediation of contaminants such as uranium in groundwater and sediments. The transport and retention of ENSPs were investigated under variable particle concentrations and dynamic flow conditions in a synthetic groundwater that mimics field groundwater chemical composition. The dynamic flow condition was achieved using a flow-interruption (stop-flow) approach with variable stop-flow durations to explore particle retention and release kinetics in saturated porous media. The results showed that the ENSPs transport was strongly affected by the particle concentrations and dynamic flows. The experimental data were used to evaluate the applicability of various kinetic models that were developed for colloidal particle retention and release in describing ENSPs transport. Both experimental and modeling results indicated that dynamic groundwater flow condition is an important parameter to be considered in exploring and modeling engineered particle transport in subsurface porous media.