A major breakthrough in seawater desalination could help billions of people access clean water.

Scientists have developed a method to make seawater evaporate faster than freshwater, offering a more efficient and eco-friendly way to combat global water shortages.

Today, up to 36% of the world’s population faces severe water shortages for at least four months each year.

By 2050, this number could rise to 75%, creating a dire need for solutions.

While desalination—turning seawater into fresh water—is one of the best options, traditional methods use a lot of energy and leave behind a large carbon footprint.

Researchers from the University of South Australia (UniSA), led by Professor Haolan Xu, have been working on a solar-powered desalination technique called interfacial evaporation.

This method is energy-efficient and sustainable, but there has been one major hurdle: seawater evaporates more slowly than freshwater because salt ions interfere with the process.

In collaboration with researchers from China, Prof Xu’s team has found a way to overcome this limitation.

By adding common clay minerals to a special hydrogel evaporator, they increased the evaporation rate of seawater by 18.8%—a remarkable improvement, as previous studies found seawater evaporation rates were 8% slower than freshwater.

The process involves using minerals like halloysite nanotubes, bentonite, zeolite, and montmorillonite combined with carbon nanotubes and sodium alginate to form a photothermal hydrogel. This material floats on the water’s surface and absorbs sunlight to drive evaporation.

Prof Xu explains that the key lies in an ion exchange process. The minerals in the hydrogel attract magnesium and calcium ions from seawater to the evaporation surface, speeding up the process. This happens naturally during solar evaporation, making it simple and cost-effective.

This new approach could be easily integrated into existing desalination systems, boosting their efficiency. Considering there are about 17,000 desalination plants worldwide, even small improvements could result in tens of millions of tons of extra clean water.

Excitingly, the hydrogel evaporator maintained its performance after months of being in seawater, proving its durability. The next step for the researchers is to refine the method further and bring it closer to real-world applications.

This breakthrough offers hope for solving global water scarcity and ensuring more people have access to clean, fresh water.