A team of engineers from the Massachusetts Institute of Technology (MIT) has developed a new device that can extract water from the air to provide safe drinking water, even in extremely dry desert environments. This innovative device operates independently without the need for batteries or solar panels.
According to a press release from MIT, around 2.2 billion people globally lack access to safe drinking water. In the United States, over 46 million people face water scarcity issues, either due to a lack of piped water or unsafe drinking water.
In an effort to help people gain access to safe and affordable drinking water, MIT engineers are working on harnessing an unconventional water source – the air. The Earth’s atmosphere contains abundant water vapor that can be collected and condensed to provide clean drinking water in regions lacking traditional water resources like rivers and lakes.
The newly developed device by MIT engineers is a black vertical panel about the size of a window, made of water-absorbent hydrogel material enclosed in a glass box coated with a cooling layer.
This hydrogel material resembles black bubble wrap with small domed structures inside. When these structures absorb water vapor, they expand, and when the vapor evaporates, they contract. The evaporated water vapor condenses on the glass, flows down through a pipe, and ultimately becomes clean drinking water.
The device operates independently without the need for batteries, solar panels, or electrical grid power supply. The research team tested the device in North America’s driest region, Death Valley in California, for over a week. Even under extremely low humidity conditions, the device was able to extract drinking water from the air at a rate of 160 milliliters (approximately two-thirds of a cup) per day.
The researchers estimate that even in arid desert environments, arranging multiple vertical panels in a small array can provide drinking water for a household. Additionally, the water production of the system increases with humidity, allowing it to provide more drinking water in temperate and tropical climates.
Unlike similar water-absorbent gel-based water collectors, MIT’s new device addresses another crucial issue. Water produced by other team’s collectors may contain salt and require additional filtration. Salt is a natural water-absorbent material, and researchers have embedded salt (usually lithium chloride) in the hydrogel to enhance its water absorption rate. However, this salt might leak along with the collected water during the final collection.
In contrast, the MIT research team added an additional ingredient – glycerol, a liquid compound that naturally stabilizes salt, to the hydrogel in their new device. This keeps the salt contained in the gel without crystallizing and leaking with the water, ensuring that the collected water’s salt content remains below the standard threshold for safe drinking water.
While the current device has only one panel with limited water collection capacity, using multiple panels simultaneously could provide enough drinking water for a household, with a relatively small footprint.
The researchers noted that this is a proof-of-concept design, with room for optimization. For instance, they can explore multi-panel designs and develop next-generation materials to further enhance the device’s internal performance.
Professor Xuanhe Zhao from MIT’s Department of Mechanical Engineering and Department of Civil and Environmental Engineering remarked, “We envision a future where you could assemble a series of these panels. Because they are all vertical, they take up very little space.”
He added, “Now people can scale it up or have it in tandem panels to provide drinking water for people and make a real impact.”
The research findings were published in the journal Nature Water on June 11.