Computational simulations of the mass transfer zone in GS adsorption column packed with Fe³⁺ type ion exchanger

In this work, a mesoporous Fe³⁺ type ion exchanger (DOW-3) was used to adsorb the geniposide (GS) involved in gardenia yellow pigment waste water. To test its viability, the mass transfer zone (MTZ) in dynamic adsorption column that plays an important role in the future scale-up of the GS adsorption process was studied systematically. Simulation of the MTZ behavior under various operation conditions in a packed adsorption column enabled the predictions of breakthrough curves of GS for the mesoporous adsorbent. Several modes of mass transport and processes taking place simultaneously, such as permeation, convection, dispersion and adsorption equilibrium were incorporated in the proposed model. Modeling process firstly affected the behavior of MTZ when it formed and moved throughout the column, and then had a much greater impact on the shape of breakthrough curve in the simulation. The dynamics of MTZ were studied under different adsorption conditions such as various column heights, flow rates and inlet concentrations. Moreover, the post-processing technique and 3D visualization of MTZ simulation results were capable of demonstrating the expanding and progressing of the MTZ related to the adsorption isotherm. The basic findings of MTZ dynamics will be very useful for process scale up. Additionally, the effective molecule docking results obtained from this study, help us fully understand the contribution of various molecular forces in the adsorption mechanism.