Cheap gel membrane can suck water every day out of thin air

The gel is made up of two inexpensive and widely available main ingredients: cellulose, which comes from the cell walls of plants, and konjac rubber, a widely used food additive. These two ingredients combine to create a gel film that can absorb water from the air then release it on demand without much energy.

First, the porous structure of the rubber attracts condensate out into the air around it. Meanwhile, cellulose is designed to react to mild temperatures by switching to hydrophobic mode, releasing trapped water.

The gel film can carry an amazing amount of water out into the air.

The team says making the gel is quite simple. The basic ingredients are mixed together then poured into molds, set for two minutes. It is then freeze-dried and then removed from the mold. Basically, it can be made into any shape needed and expands fairly easily at low cost.

In tests, the gel film was able to pull an amazing amount of water out into the air. At 30% relative humidity, it can produce 13 L (3.4 gal) of water per day per kilogram of gel, and even when the humidity drops to a low 15%, for desert air it can still produce more than 6 L (1.6 gal) a day per kilogram.

That's a huge improvement over the other water harvesters they've mentioned over the years. The previous peak was 8.66 L (2.3 gal), but that was in air with much higher humidity. Others peaked at 5.87 L (1.55 gal) at 30% humidity, or as low as 1.3 L (0.3 gal).

The efficiency of the new gel film can be further improved, the team says, by creating thicker films, absorbent layers or other plaque forms of the material. Perhaps most importantly, the material is extremely cheap to manufacture, at around $2 per kilogram. It's the other major factor in scaling the technology and bringing it to remote areas and developing countries, where it needs it most.