A new method for evaporating seawater faster than fresh water represents a meaningful progress in desalination technology which can benefit billions of people.
Currently, approximately 36% of the 8 billion people in the world suffer from it severe shortage of fresh water for at least four months of the year, and this figure could increase to 75% in 2050.
Seawater desalination is one of the most effective strategies to alleviate the impending shortage, But existing processes consume enormous amounts of energy and leave a large carbon footprint.
Professor Haolan Xu,a materials researcher at the University of Saxony,has collaborated with researchers in China on a project to develop a simple but effective strategy to reverse this limitation. These new findings were published in the journal Advanced materials.
By introducing common, inexpensive clay minerals into a photothermal hydrogel floating evaporator, the team achieved seawater evaporation rates 18.8% higher than pure water. This is a significant progress,as previous studies have shown that evaporation rates of seawater were around 8% lower than pure water.
“The key to this progress lies in the ion exchange process at the air-water interface,” says Professor Xu in a statement.
“The minerals selectively enrich seawater magnesium and calcium ions on evaporation surfaces, increasing the evaporation rate of seawater. This ion exchange process occurs spontaneously during solar evaporation, making it very convenient and economical.“.
Considering the global desalination market, which has approximately 17,000 plants operating worldwide, even small decreases in desalination performance can result in the loss of tens of millions of tons of clean water.
“This new strategy, which could be easily integrated into existing evaporation-based desalination systemswill provide further access to huge quantities of clean water, which will benefit billions of people around the world,” says Professor Xu.
the researchers say the hydrogel evaporator maintained its performance even after months of immersion in seawater.
The next steps will involve exploring further strategies that can make the evaporation of seawater faster than the evaporation of pure water and their application in practical seawater desalination.