Numerical Investigations into the Influence of Operational Parameters on Diffusion and Migration in Electrodialytic Nitrate Removal

A comprehensive two-dimensional (2D) macro-scopic model to describe an electrodialysis system to remove nitrates from a model solution was described. This model is intended to quantify the diffusion and migration contributions to global mass transport. We have chosen nitrate removal because of its environmental and sustainability importance. No important changes in flux values are found with an increase in the flow rate, indicating that in this particular case, where only a 1:1 electrolyte is split in the central compartment, migration effects govern the transport of ionic species involved in electrodialysis. Then, the only experimental parameter that has a considerable influence is the externally applied current. The model obtained is capable of describing the electrodialytic nitrate removal. For this reason, the increment of flow rate in this kind of system must be taken carefully since pumping energy consumption by the increase in the flow rate could increase considerably. This galvanostatic model provides information that could be helpful to better understand the ED process and to improve the electrodialysis design.

Automated summary

A comprehensive two-dimensional macroscopic model was described to analyze an electrodialysis system for nitrate removal. The model focuses on quantifying the effects of diffusion and migration on mass transport. The study found that an increase in flow rate does not significantly affect flux values, while the externally applied current is the only experimental parameter with considerable influence.