Modeling shock layers in ion‐exchange displacement chromatography

Abstract

Abstract In ideal displacement chromatography (systems with infinite mass‐transfer kinetics), various solutes are separated by sharp discontinuities. In real systems, however, the shocks are eroded into shock layers because of the finite rates of mass transfer. The thickness of these shock layers, which can reduce the yields achievable in these systems, depend on the flow rate, particle diameter and the “difficulty” of these separations. The steric mass action formalism of ion‐exchange chromatography was used in concert with a solid film linear driving force model to describe the effects of flow rate, particle diameter, and the degree of difficulty of the separation on ion‐exchange displacement systems. Simple pulse techniques are employed to estimate the thermodynamic and mass‐transfer parameters. The simulations are then compared to experimental results over a range of conditions. The results demonstrate that this relatively simple modeling approach can be employed to describe the behavior of these nonideal displacement systems.