Microscale Simulation of Nanoparticles Transport in Porous Media for Groundwater Remediation

Micro and Nanoscale zerovalent iron (MZVI and NZVI) is one of the most promising reagent for the remediation of contaminated groundwater; these particles, in fact, can efficiently degrade, through redox reactions, recalcitrant and carcinogenic compounds. The aim of this study is to simulate at the microscale the transport of iron nanoparticles, their interaction with the porous media and their deposition on the aquifer material. The simulations have been carried out with a Langrangian approach implemented in COMSOL Multiphysics 4.2a. The model under study includes the relevant forces acting on the single particles such as drag, Brownian, gravity, Van der Waals and electric double layer force. The simulation results can deliver, thanks to this microscale description, an estimation of the attachement efficiency that can be used for macroscale simulations and compared with the relationships obtained by the clean bed filtration approach.