The world is running short of clean water at a time when the global population is growing.

What to do? Pull water out of the air.

Researchers at the Massachusetts Institute of Technology are doing it using a hydrogel, a cross-linked network of large molecules that holds water.

They salted the hydrogel with lithium chloride, which is able to absorb 10 times its own mass in water vapor. 

The salt pulls water—fog, humidity, steam, whatever form the water takes—from air and the hydrogel holds it until it’s collected.

The material even collects a useful amount of water at 30-percent humidity, which is roughly typical humidity in a desert at night, the researchers said.

The material can be made cheaply at commercial scale, according to the developers.

The key challenge now is to coax the salt to absorb vapor faster so it can deliver useful amounts of water more than once a day.

TRENDPOST: As developed, this material becomes another competitor for lithium, already becoming scarce in comparison to demand for it by the electric vehicle industry.

However, two things can free up lithium for this new use.

First, a variety of alternative battery chemistries—for vehicles and other mobile devices—are in development that reduce or eliminate the need for lithium.

Second, artificial intelligence is already at work designing new materials to order: researchers specify what a molecule is to be able to do and AI simulates countless chemical reactions to see which are promising enough to test on the bench.

As MIT’s group develops its hydrogel further, materials for its manufacture also will evolve.

MIT’s water-loving salted hydrogel

Photo: MIT

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