Mathematical modeling of desalination and brine concentration processes in batch recirculating electrodialysis system

Abstract

This study presents the development of a mathematical model to accurately predict the dynamics of salt and water transport in a batch electrodialysis system used for either NaCl desalination or LiCl brine concentration. The primary aim of the model is to simulate the desalination of high-salinity water under specified current density conditions. The governing equations for the electrodialysis stack and associated tanks were formulated and solved using numerical methods. Model predictions were validated against experimental data, demonstrating high accuracy: the deviation between measured and predicted tank concentrations was within ±2 % for both NaCl and LiCl systems. In addition, the study investigated how initial salt concentration, current density, and flow rate influence system performance. The results show that system efficiency is significantly affected by the initial brine concentration. Increasing the salt concentration from 5 wt% to 10 wt% and 20 wt% reduced desalination efficiencies by approximately 67 % and 93 %, respectively. Moreover, salt flux improved with higher current density, with a 71 % increase in desalination observed when current density was raised from 100 A/m2 to 400 A/m2. © 2025 Elsevier Ltd