  We analyse a PDE system modelling poromechanical processes (formulated in
mixed form using the solid deformation, fluid pressure, and total pressure)
interacting with diffusing and reacting solutes in the medium. We investigate
the well-posedness of the nonlinear set of equations using fixed-point theory,
Fredholm's alternative, a priori estimates, and compactness arguments. We also
propose a mixed finite element method and rigorously demonstrate the stability
of the scheme. Error estimates are derived in suitable norms, and numerical
experiments are conducted to illustrate the mechano-chemical coupling and to
verify the theoretical rates of convergence.
