A review of transport of nanoparticles in porous media

Transport and deposition of nanoparticles in saturated porous media is a topic of great importance in several fields of science and engineering. Colloidal transport is a peculiar multiscale problem, as pore-scale phenomena have an important impact on the transport at the larger scales. This study provides an overview of several numerical techniques employed in the investigation of pore-scale flow and transport in porous media. First, different approaches used to represent soil pore structure are analyzed. Then, particle transport is analyzed in both the Lagrangian and Eulerian theoretical frameworks, and the solutions proposed in the literature for the description of the forces acting on the particles are revised. The last part of the review presents approaches for the upscaling from pore scale to the macroscopic scale. To link microscale deposition processes to the macroscale description of particle transport, the concept of the single collector efficiency is commonly applied and is discussed in this review along with alternatives.