Indeed, a team of engineers at MIT has just presented a super-absorbent material that can extract a record amount of moisture from the air, even in very dry conditions (humidity below 30%).

The secret is…in the diaper

Specifically, this team works with hydrogels, "elastic gels and slippery gels" that are made primarily of water and a little bit of reticulated polymer. It's, as I say, a very common material because it's used in disposable diapers, and in fact, researchers recognize that a lot of time has been spent thinking about how they could "make this work just as well to absorb the vapor from the air."

The image of a lot of top-notch engineers and scientists doing brainstorming in front of a diaper is reckless.

How did they do that?

Looking for solutions to the problem, researchers found that there are certain salts that have proven to be very effective in extracting steam from the air. Lithium chloride, for example, "is capable of absorbing more than 10 times its own mass in moisture".

That is, lithium chloride alone can get water out of the air, the problem is that it cannot store it (just what the hydrogel does). What if they were trying to combine those two characteristics into one thing?

They weren't the first to try. In fact, previous researchers found that "there was a limit" to how much salt you can put into a hydrogel of that kind. about "4 to 6 grams of salt per gram of polymer". And that, though it's better than anything, didn't yield any great results either: about 1.5 grams of vapor per gram of material (30 percent relative humidity).

To circumvent this problem, they simply did nothing. They literally deposited the hydrogel in a saline solution, as the other investigators had done; but instead of removing it at 24-48 hours, they left it for a month.

As expected, the hydrogel had continued to incorporate salt until it reached 24 grams. The result is a transparent, godly material that works much better than the previous ones: it's not a disruption, but it shows us the way to get it. It is then enough to heat and condense it to obtain pure water. Yes, on paper, it's as promising as it looks.

• Mostly for applications. And it's that, even if it doesn't seem like it, 'drying the air' is a very useful thing. Not only to create passive water collectors in areas where droughts are recurring, but for things like air conditioning equipment (where you could save energy).
• The problem is always: making it viable and cost-effective. It's not only a matter of learning how to make it quickly and cheaply; it's also finding a way to get that water out of the material for easy recycling.