Researchers develop electrochemical method to extract magnesium from seawater

Researchers have developed a new electrochemical method to extract magnesium from seawater more sustainably and cost-effectively. Currently, most magnesium is sourced from mineral deposits in rocks, a process involving energy-intensive mining, crushing, and heating.

As reported in ACS Energy Letters, the new system utilizes specially engineered bismuth electrodes to selectively remove magnesium ions. While magnesium is the second most abundant positively charged ion in seawater after sodium, the high concentration of sodium makes separation difficult. Traditional extraction methods often rely on heavy chemical use or expensive membranes.

The new approach uses an electrochemical cell with thin bismuth sheets and two channels separated by a membrane. By applying an electric current, the electrodes modulate the local acidity of the seawater, allowing magnesium to be collected as magnesium hydroxide. By reversing the electric field and liquid flow, the magnesium hydroxide can be converted into magnesium chloride, which has extensive industrial and commercial applications.