Neue Entsalzungstechnik nutzt Temperaturgradienten und bis zu 80 % weniger Energie

Researchers from The Australian National University have developed a new desalination method called thermodiffusive desalination ([Nature Communications](https://www.nature.com/articles/s41467-024-47313-5)) , which significantly reduces energy requirements by about 80% compared to traditional methods. This technique avoids the negative environmental impacts and high costs associated with existing desalination technologies, such as reverse osmosis and thermal methods.

[Thermodiffusive desalination](https://scx2.b-cdn.net/gfx/news/hires/2024/new-electricity-free-d-1.jpg) uses low-grade heat from sources like sunlight or industrial processes. It operates on the principle of thermodiffusion, where salt migrates to the cooler side of a temperature gradient without needing a phase change. In their prototype, seawater is pushed through a narrow channel with a hot top plate (over 60°C) and a cool bottom plate (20°C). This setup produces low-salinity water from the top and high-salinity water from the bottom. Each pass reduces salinity by 3%, eventually lowering seawater salinity from 30,000 ppm to below 500 ppm after multiple cycles. At that level and this cost the technique produces water suitable for agricultural use (maximum 2000 ppm), an area unaddressed with current, more expensive techniques, and is still suitable for human consumption (maximum 500ppm).

This method does not require membranes or ion-adsorbing materials, avoiding issues like fouling and corrosion. It is scalable and suitable for use in developing countries and remote regions, providing a decentralized approach to water security.

“There are thousands of remote regions, and dozens of small countries around the world facing water scarcity,” Dr Torres said. “They are in the places where climate change is having the worst impacts, drying their land and destroying their agriculture. We need thermodiffusive desalination to decentralise the process and sustainably bring water security these regions.”

The researchers are currently developing a larger device for use in Tonga, powered by a solar panel, to address the island’s severe drought conditions.