Newly Developed Gel Extracts Drinking Water From The Air

But that might be about to change, a prototype developed by Peng Wang from the Water Desalination and Reuse Center at Kaust has shown the potential to overcome this problem inexpensively and reliably.

The device is based around the cheap, stable, nontoxic salt, calcium chloride.

Hydrogel absorbs while staying solid

This salt has the ability to absorb so much vapor from its environment it will become a pool of liquid.

“The deliquescent salt can dissolve itself by absorbing moisture from air,” says Renyuan Li, a Ph.D. student in Wang’s team.

While the salt has the impressive ability to absorb water from the air, the fact it turns it into salty water is less useful. To beat the problem, the researchers incorporated the salt into a polymer known as a hydrogel.

Carbon nanotubes allow water extraction via sunlight

This material can absorb a lot of water while remaining solid. A small amount of carbon nanotubes were also added to the mix that will assist the captured water vapor to be released.

Just 0.42 percent by weight were added, but the material impressive ability to absorb sunlight and convert the captured energy into heat is essential to extracting the liquid.

A simple 35-gram prototype of the completed extraction device was left outside and managed to collect 37 g of water in weather conditions of 60 percent humidity.

Researchers work to scale up a prototype

The following day, after absorbing sunlight for just 2.5 hours almost all of the absorbed water was released and collected.

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“The hydrogel’s most notable aspects are its high performance and low cost,” says Li.

The researchers say that if the prototype was scaled up to produce 3 liters of water per day, an amount considered the minimum water requirement for an adult, the cost of the gel could be as low as half a cent per day.

The research was published in the recent edition of Environmental Science and Technology.