Multi-functional electrodialysis process to treat hyper-saline reverse osmosis brine: producing high value-added HCl, NaOH and energy consumption calculation

Abstract

Addressing the environmental challenges of desalination brines is becoming increasingly crucial, especially in regions reliant on seawater desalination. This study focuses on electrodialysis (ED) technology, a solution that transforms concentrated brines into valuable acids and bases like sodium hydroxide (NaOH) and hydrochloric acid (HCl). The current research optimizes ED operating conditions (initial brine concentration, voltage, and treatment time) by using design expert^®software, aiming to minimize energy consumption and maximize acid/base concentration. The current research resulted, that under optimal conditions (75 g/L as initial salt concentration and 24 V applied for 6 h), ED produced HCl and NaOH at concentrations of (0.86 M and 0.93 M) for internal use in water treatment plants. Additionally, the study demonstrated the ability to lower brine salinity to acceptable discharge levels (35 g/L) within a short timeframe (2 h). Notably, at optimized ED conditions offering a significant potential for cost savings and sustainability improvements.