A New Pump Can Reduce Salt Content From Seawater

Scientists have designed a revolutionary solution that could reshape desalination and water purification after making a membrane that can transport ions through water without relying on mechanical systems or chemical reactions.

The international research team, including scientists from Germany’s Helmholtz-Zentrum Hereon, introduced a novel type of io pump that uses ultra-thin metal layers on either side of a porous membrane.

These layers control the movement of electrically charged particles. In contrast to traditional electrochemical systems, which rely on energy-intensive reactions, this approach uses rapid electrical switching to promote ion flow.

"This work introduces a new way to drive continuous ion transport in water by harnessing ratchet mechanisms in nanoporous materials," Francesca Toma, PhD, head of the Hereon Institute of Functional Materials for Sustainability in Teltow, Germany, pointed out.

The innovation represents a significant advance in fundamental electrochemistry. It reportedly relies on a simple physical effect. When a low electrical voltage is applied and rapidly switched on and off, the metal interfaces undergo repeated charging and discharging cycles.

Small imbalances in this process generate a controlled flow of ions and effectively pump them without the need for chemical reactions or moving parts. This is the first time the effect has been used for ion transport.

"Controlling the movement of ions through liquids is critical for many technological and biological processes," the researchers emphasized.

To demonstrate the approach’s potential, the team integrated the membrane into a compact desalination system. In lab tests, the device was able to reduce the salt content of water by up to 50 percent while operating at very low voltages.

Importantly, the system achieved this without pumps, filters that require pressure, or chemical additives, all factors that typically drive up the energy cost, as well as the complexity of existing desalination technologies.

The project brought together researchers from the University of California, Irvine, Tel Aviv University, the University of Massachusetts Boston, as well as Lawrence Berkeley National Laboratory (LBNL).

The results highlighted the membrane’s potential for developing highly energy-efficient water purification and desalination solutions. The membrane could also enable selective separation of ions with the same electric charge by exploiting subtle differences in how ions behave under an electric field.