A team of researchers at Massachusetts Institute of Technology (MIT) have developed a new material that can pull moisture directly from the air, even in arid climates. The material can even turn this moisture into drinkable water and is described in a recent article published in Advanced Materials.
Specifically, researchers turned to hydrogel materials, which are often found in materials like diapers and are known to be super absorbent. In the past, other teams have attempted to do something similar with other hydrogel materials, using a range of different materials (usually, salts) to create a material that can absorb moisture from the surrounding atmosphere. These include salts such as rock salt, which have a good track record of being able to absorb moisture from the surrounding atmosphere.
As part of their study, researchers chose lithium chloride, which was already proven to be an effective option for pulling in moisture. However, a vessel was needed to contain the moisture that lithium chloride pulled in. Using hydrogels, researchers were able to create a material that could both take in moisture and expand to accommodate more and more water.
And the more salt a hydrogel could hold, presumably, the more water it could absorb. The problem, however, was that many previous attempts had capped the record amount hydrogels could hold at about six grams per gram of polymer used. To see if it was possible to incorporate more salt, researchers soaked their hydrogel materials in salt water and found that, after 30 days, the hydrogels were holding around 24 grams of lithium chloride per gram of polymer. When finally testing their materials in an arid environment with around 30% humidity, the hydrogel absorbed roughly 1.79 grams of water per gram of polymer, a record.
As humans grapple with the effects of climate change, such as droughts that can affect access to water for entire populations, the need for new ways to supply drinking water are of paramount importance. The team’s work has led to a material that is highly effective and low in cost, which provide solutions in the future.
Sources: Science Daily; Advanced Material
