In certain parts of the world like Peru, Bolivia, Chile, Morocco, and Oman, fog is like a guest that overstays its welcome.
It’s always there! And for a long time, people living in these foggy areas have come up with a clever trick.
They hang big nets outside to catch the tiny droplets of water from the fog. These droplets gather on the net, trickle down, and are collected in containers.
It might sound odd, but in areas where it doesn’t rain much, this is an inventive way to get water for drinking, cooking, and cleaning.
And you’d be surprised—just one of these nets can catch several hundred liters of water in a day!
But here’s the catch: if the air is dirty and polluted, so is the water from the fog. So in big cities, this fog-water isn’t really safe to drink or cook with unless it’s cleaned first.
This is where a team of smart researchers from ETH Zurich steps in. They thought, “What if we could catch this water and clean it at the same time?”
They designed a special net using metal wires and covered it with a mix of special materials and something called titanium dioxide.
The materials help in collecting water droplets faster, making sure they don’t fly away with the wind. But the real magic happens with titanium dioxide—it breaks down nasty stuff in the water droplets, making the water clean and safe.
Ritwick Ghosh, one of the brains behind this project, explained that this new system not only catches the fog-water but also cleans it. This means that even in cities with lots of air pollution, this water will be good to use.
Now, you might be wondering how they keep the cleaning power of titanium dioxide active. Here’s the cool part—it has a “photocatalytic memory.”
All it needs is about half an hour of sunlight, and it’ll be ready to clean water for a whole day! And even when the sun isn’t shining, which is common in foggy areas, this special net keeps working in the dark for quite a while.
The researchers wanted to make sure their idea worked, so they tested it in a lab and also set up a small working model in Zurich. The results?
The net caught 8% of the water from the man-made fog they created and cleaned up 94% of the pollutants they added to it. This included tiny diesel particles and a chemical called bisphenol A, which isn’t good for us.
But wait, there’s more! This fancy fog-catching net can be used in other ways, too. Thomas Schutzius, another scientist on the team, mentioned how it could be useful in power plants.
When power plants are cooled down, they release steam into the air. In countries like the US, a lot of fresh water is used for cooling these plants.
Why let all that water just disappear into the sky? Schutzius suggests catching and cleaning some of that water before it’s gone, especially if it can be returned to the environment.
All in all, the hope is to make more use of the water from fog and steam, which hasn’t really been appreciated before.
By doing so, it might help places that don’t have a lot of water, giving them a fresh, clean, and unexpected source.
The study was published in Nature Sustainability.
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Source: ETH Zurich.
