Investigation of water transport phenomena in electrodialysis for high-concentration brine production

This study explores water transport phenomena during brine concentration using an electrodialysis (ED) system. Desalination experiments were performed under constant current and constant voltage conditions to assess the effects of operational parameters on desalination performance and water transport mechanisms. The results revealed that electro-osmotic water transport averaged 3.03 g of H 2 O per g of NaCl, consistent with the ion hydration number. Based on these findings, the maximum concentrate concentration achievable via ED was estimated to be approximately 24.8 wt% in this study. At lower current densities, osmotic water transport became more prominent, resulting in reduced concentrate concentrations and decreased current efficiency. Conversely, higher current densities significantly improved current efficiency and concentrate concentration, albeit with increased energy consumption. This study offers valuable insights into optimizing ED operational parameters to enhance process efficiency and facilitate the effective production of high-concentration brine. • Electro-osmotic and osmotic water transport in ED was investigated. • Electro-osmosis moves 3.03 g of water per 1 g of NaCl in ED systems. • The maximum brine concentration achievable via ED is affected by water transport. • Higher current density enhances current efficiency and minimizes osmotic transport. • Osmotic water transport depends on the concentration gradient and desalination duration.