Numerical modeling of the wastewater purification process from heavy metals using the electrodialysis method

Abstract

This study aimed to develop a mathematical model of ion transport in a system featuring a free electrolyte with membrane barriers and to investigate the interaction between diffusion and migration flows in different parts of the channel. The article presents the results of numerical modelling of the wastewater treatment process for copper ions using the electrodialysis method. Electrodialysis is a promising technology for removing dissolved ions from aqueous media due to its high efficiency, environmental safety, and the possibility of regenerating valuable components. The study developed a mathematical model that enables the simulation of how heavy metal ions, specifically copper ions (Cu²⁺), migrate through an electrodialysis cell under the influence of an electric current. The model is implemented in the COMSOL Multiphysics environment, which enables the consideration of all the above aspects with high accuracy. The modelling process analysed the features of the transport of Cu²⁺ and SO₄²⁻ ions in the electrodialysis unit. Opposite directions of migration flow for cations and anions were found, which is consistent with the nature of their electric charges. Spatial heterogeneity of flow distribution was also established, and the need to take these features into account when optimising electrodialysis processes was substantiated. The modelling results confirm the effectiveness of electrodialysis for removing heavy metal ions from wastewater and indicate critical areas where efficiency losses may occur or ion concentrations exceed permissible limits. The obtained data can be used to improve the geometry of the channels, the membranes configuration and energy efficiency of electrodialysis units.