Numerical Simulation of Solid Phase Adsorption Models Using Time-Integrated, Up-Winded Finite Element Strategies

The effectiveness of bio-pharmaceuticals for the treatment of a wide range of diseases has led to increased research to improve bio-separations processes, including the use of high-capacity ion-exchange membranes. In this paper, we develop and analyze a numerical scheme for approximating solutions to mathematical models associated with advection-dominated, solid phase adsorption processes. The scheme utilizes streamline-up-winded continuous Galerkin finite elements to discretize the transport equation. Temporal integration is used to handle the nonlinear adsorption term. We show solvability of the up-winded discrete scheme and provide numerical verification of expected convergence rates. We compare numerical results with experimental data and demonstrate the effects of a variety of flow profiles on the model results. We also show up-winding is needed to produce stable and accurate results for these models, especially for coarse meshes.