MIT's new device can extract drinking water from air
What's the story
Researchers at the Massachusetts Institute of Technology (MIT) have developed a revolutionary device that can extract drinking water from the air without any power or filters.
The innovative technology, called a passive atmospheric water harvester, uses a vertical panel of hydrogel to absorb water vapor from the atmosphere.
This method is not entirely new but has been improved upon by MIT engineers with some clever design tweaks.
Innovative approach
How the device works
The hydrogel used in the MIT device is designed like a sheet of bubble wrap, with small 'domes' that expand when they absorb water.
This design increases the surface area and capacity to absorb water vapor.
The hydrogel is enclosed in a glass layer coated with a cooling polymer film.
As the absorbed vapor evaporates, these domes shrink back in an origami-like manner, and the evaporated vapor condenses on the glass surface and flows down through a tube.
Salt stabilization
Improvements over traditional designs
In traditional water harvester designs, micro- or nano-porous hydrogels are infused with salts to improve absorption.
However, these salts can leak out with the collected water, making it undrinkable.
The MIT team overcame this issue by using a hydrogel with a microstructure that doesn't have nanoscale pores for salt to escape from.
They also added liquid glycerol to stabilize the salt and prevent it from crystallizing and leaking out when water flows through the tubes.
Testing results
Device outperformed other passive designs
The MIT team tested their window-sized device in California's arid Death Valley, where it produced between 57ml and 161.5ml of drinking water per day across different humidity levels.
They found that their invention outperformed other passive and even some actively powered designs in the driest conditions observed in the valley.
However, they believe an array of these vertically hydrogel panels could be deployed in water-scarce regions to deliver larger amounts for an entire household.