Researchers have developed a way to collect clean water from fog. This new technology uses a material that purifies water from polluted air as it is captured.
Peru’s capital, Lima, is one of the driest cities in the world, despite being located next to the Pacific Ocean. The cool air rising from the ocean into the Andes rarely condenses, causing very little rainfall. To solve this problem, residents have been using nets to extract moisture from the air for years, sometimes collecting hundreds of liters of water per day.
This simple technique is also used in other arid regions like Bolivia, Chile, Morocco, and Oman. However, there is one significant challenge: in areas near cities and industrial zones, the air is often polluted. The water collected from fog contains harmful pollutants and must be thoroughly purified before it can be used for drinking or cooking.
Scientists develop a self-purifying solution
To address this problem, researchers from ETH Zurich and the Max Planck Institute for Polymer Research in Mainz have modified fog nets to clean the water as it is collected. The team behind this innovation includes material scientists Ritwick Ghosh and Thomas Schutzius. They coated metal mesh with a polymer and titanium dioxide mixture. This coating works as a catalyst, breaking down harmful pollutants in the fog droplets.
Schutzius has since moved to the University of California in Berkeley, while Ghosh continues his research in Mainz.
Low-energy solution shows promising results
The most impressive aspect of this new technology is its efficiency. The fog nets require very little maintenance and no external energy source other than sunlight. Titanium dioxide only needs UV light to regenerate, making it a cost-effective solution. In a test setup in Zurich, the researchers were able to remove 94 percent of organic compounds, including diesel droplets and other toxic substances. Remarkably, the material remains chemically active for some time even in darkness.
“Our goal now is to optimize the process so the purification works continuously, day and night,” Ghosh explained. The team is already in talks with start-ups and potential manufacturing partners for large-scale production, and interest has been expressed from companies in the U.S., Canada, and Switzerland.
