Due to abrupt changes in our environment, scientists are working tirelessly to find ever more ingenious ways to meet humanity’s needs, such as, in this case, getting clean water from the desert air.
A new prototype device, developed by the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, is capable of absorbing water and then releasing it on request. It’s the kind of invention that could prove invaluable to people living in arid and desert regions, where water is already rather scarce.
How does the device work?
The key to this device is a special hydrogel based on calcium chloride. It can be irresistible to water, but it generally turns to a salty liquid as it absorbs the steam. But thanks to the work of the engineers, the hydrogel mixture keeps it in a solid form until the water is needed.
“The most notable aspects of the hydrogel are its high performance and low cost,” says Renyuan Li, co-author of the study in the journal Environmental Science & Technology .
With an estimated 13 trillion tons of water vapor in the atmosphere, the power to collect some of that water to keep humans hydrated would be a breakthrough, especially for the hundreds of millions of people in the world without a source of water. adequate water.
Although calcium chloride has been tried to use before, it has been difficult to make it practical as a material for storing water.
How did they do it?
The experts solved the problem by converting the salt into a polymer so that it would hold its shape until heated. In addition, the carbon nanotubes would help release the water.
The idea is that the device can capture water from the air at night and then release it when it warms up during the day.
This is exactly how the prototype tested by the researchers works: 35 grams of hydrogel were able to capture 37 grams of water overnight with a relative humidity of around 60%.
The next day, 2.5 hours of sunshine were enough to release 20 grams of water, which was collected in a ready-to-drink device.
The hydrogel is now ready to use again, the researchers report.
However, scientists are still not satisfied, they hope to modify the design so that the water is released continuously and not intermittently. These devices can save lives, which makes them an incredibly important tool.
There are many initiatives underway , but this new hydrogel-based device is ticking a lot of the boxes necessary for its massive success.
“This type of atmospheric water generator is cheap and affordable, works perfectly with a wide range of humidity, does not need electricity, and is therefore especially suitable for the production of clean water in remote areas,” the researchers write.
Reference: Hybrid Hydrogel with High Water Vapor Harvesting Capacity for Deployable Solar-Driven Atmospheric Water Generator. Renyuan Li, Yusuf Shi, Mossab Alsaedi, Mengchun Wu, Le Shi, and Peng Wang. Water Desalination and Reuse Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia . Environ. Sci. Technol. , 2018, 52 (19), pp 11367–11377 / DOI: 10.1021 / acs.est.8b02852
