Study of the behavior of solid reagents in aquifer confined under different conditions of chemical kinetics

Abstract

This research presents a numerical solution of the multicomponent reactive transport problem in a two-dimensional saturated  porous media  under  steady  fow  conditions. The  solved  problem  is  a  system with  two  simultaneous reactions,  one  instantaneous  and  another  slow  relative  to  the  groundwater  fow  and  the  physical  processes  of solute transport, assuming that the aquifer is physically homogeneous and does not exhibit any temporal or spatial variations in temperature.

Based on the methodology proposed by Molins et al. [1] and developed by Donado et al. (submitted to Water Resour. Res.)  [2],  the  reactive  transport  system  is decoupled  into  two components, one  for each  reaction  (equilibrium and kinetic). Thus,  the conservative component represents  the equilibrium reaction and  the kinetic component  the slow reaction. This way the multicomponent reactive system is reduced to the solution of two partial differential equations.

The main outcome of this research is that the equilibrium reaction rate can be defned as a function of the mixing and the kinetic reaction rate.