Salt Splitting
There is growing pressure on industry to reduce the amount of process wastewater.
The energy transition and the need to develop circular economy models have put the spotlight on the topic of wastewater.
The commitment that industrial companies must make to the treatment and recovery of harmful emissions is increasingly important, especially concerning wastewater discharges.
Electrochemical salt splitting is a new and emerging technology for markets that has circular economy principles in mind and can offer a solution to the growing pressure of treating salt-contaminated wastewater. Electrochemical salt splitting, also known as electrochemical desalination or electrochemical salt removal, is a process that uses electricity to separate salts. This technique allows the regeneration of acids and bases from their salts and the production of clean water. This establishes a closed-loop system that can dramatically reduce net reagent consumption and water usage, while eliminating the need to dispose of large quantities of salt and contaminated water.
How does the electrochemical salt splitting process work?
The process typically uses an electrochemical cell where electrodes are immersed in a salty water solution. When an electric current is applied through the electrodes, it initiates water electrolysis. This means that the electrical energy breaks down the water molecules into oxygen and protons at the anode and hydrogen and hydroxyl ions are produced at the cathode according to the following reactions:
2H₂O → O₂ + 4H⁺ + 4e⁻ (anode)
2H₂O + 2e⁻ → H₂ + 2OH⁻ (cathode)
Meanwhile, these electrical currents cause the migration of ions towards the oppositely charged electrodes due to their attraction. Specifically, the anions migrate towards the anode where positively charged ions are formed (the H+ protons) while cations move towards the cathode where negatively charged ions, the hydroxyl OH-, are produced. These are the key movements that allow the separation of ions.
As a result of this migration, the salt ions are directed toward the electrodes, clean water remains in the middle, and all three components can be collected separately in different areas of the electrochemical cell.