Mathematical Modeling of Transport and Retention of Nano-Scale Particles in Homogeneous Porous Media

The production, use, and disposal of nanomaterials could lead to their appearance in the environment, creating high exposure to humans and the ecosystem and affecting mobility and bioavailability of other toxics. Mathematical models were performed to validate experimental data investigating the transport and retention of nano-scale particles in water-saturated porous media. The aqueous suspension of nano-particles was introduced into several columns packed with sand at different flow rates. Effluent concentration and retention profile data were accurately simulated using a numerical model that solves conservation of mass and momentum, and the interaction and deposition of nano-particle with bed material. The mathematical model is based on porous media approach with a specific area-to-volume ratio pre-specified. The model predications were performed using computational fluid dynamic software, FluentŪ. The model accounted for the attachment kinetics of nano-particle to the bed and a limiting retention capacity. The retention capacity was estimated using batch experiments, while the reaction kinetics is an approximate lump of all the mechanisms that occur to the nano-particle through its journey within the column.