Bipolar Electrodialysis for NaCl Conversion into NaOH and HCl
DESALT Bipolar Electrodialysis (EDBM or BPED) is a versatile technology with a wide range of applications across various industries.
One of its primary applications is the conversion of Sodium Chloride (NaCl) into Sodium Hydroxide (NaOH) and Hydrochloric Acid (HCl).
This process not only facilitates the production of these essential chemicals but also plays a key role in the desalination industry by recovering valuable components from waste brine.
Bipolar Electrodialysis for NaOH & HCl Production - Working Principle
Bipolar Electrodialysis for NaCl Conversion Into NaOH & HCl
Bipolar electrodialysis works by creating an electric potential across a stack of alternating cation-exchange and anion-exchange membranes, with bipolar membranes placed between them. These bipolar membranes are key because they are capable of dissociating H2O into hydrogen ions (H⁺) and hydroxide ions (OH⁻) at the interface.
The process involves feeding a solution of NaCl between the membranes. When an electric current is applied, the following reactions occur:
-
Ion Migration: The Na⁺ ions migrate towards the cation-exchange membrane, while the Cl⁻ ions move towards the anion-exchange membrane.
-
Water Dissociation at Bipolar Membranes: thanks to the bipolar membranes, water is dissociated into H⁺ and OH⁻ ions. This is where the actual conversion happens. The H⁺ ions formed at the bipolar membrane interface create hydrochloric acid (HCl), and the OH⁻ ions form sodium hydroxide (NaOH).
-
NaOH and HCl concentration: The produced NaOH (basic solution) is concentrated in the cation-exchange membrane side, while HCl (acidic solution) forms on the anion-exchange membrane side.
Advantages of Bipolar Electrodialysis for NaOH and HCl Production from LiCl Solutions
High Purity
-
Bipolar Electrodialysis relies on selective ion exchange membranes (AEM, CEM, and BPM), which ensure that only specific ions are transported through the membranes. This selectivity minimizes contamination from other ions present in the feed solution.
-
At the same time, the bipolar membranes provide a clean and controlled source of hydroxide ions. This precision in ion generation and movement enhances the purity of the final base and acid products.
-
Traditional chemical methods often introduce impurities during the reaction processes or through the use of reagents. EDBM, on the other hand, operates under a controlled electric field, significantly reducing the introduction of extraneous substances.
We design and manufacture lab, pilot, and industrial scale solutions for Bipolar Electrodialysis.
Get in touch today for more info.