A Lagrangian Method for Reactive Transport with Solid/Aqueous Chemical Phase Interaction.

A significant drawback of Lagrangian (particle-tracking) reactive transport models has been their inability to properly simulate interactions between solid and liquid chemical phases, such as dissolution and precipitation reactions. This work addresses that problem by implementing a mass-transfer algorithm between mobile and immobile sets of particles that allows aqueous species of reactant that are undergoing transport to interact with stationary solid species. This mass-transfer algorithm is demonstrated to solve the diffusion equation and thus does not introduce any spurious mixing. The algorithm is capable of simulating an arbitrarily small level of diffusion, and can be combined with diffusive random walks to simulate the desired level of diffusion in a reactive transport system.