26. Models of Sorption Type for Colloid-Facilitated Transport in Aquifers

This chapter considers sorption-based numerical models simulating 1D migration of chemical species in the presence of mobile reactive colloids. One of the model extensions includes a module for simulating the migration of a colloid mixture characterized by heterogeneous distributions of particle size and sorption properties. The modeling analysis is accompanied by simple analytical assessments based on characteristic solutions. The simulation and analytical results indicate that species binding to colloids may lead to a considerable enhancement of the colloid-mediated solute migration. The differences in the kinetic constants for sorption and desorption as well as sorption irreversibility appreciably affect the transport rate at local and regional scales.