Nearly everyone has used some kind of analogy for incredible odds in reference to water in the desert. We all know that the very definition of a desert is the lack of water and a major problem for the people living there, so imagine what it would be like to be able to pull water out of the blue, clear sky? Another analogy intended to express the idea that you could get something from nothing, but scientists are doing just that. Scientists have refined an old invention to create a device that can pull water from air.
What invention was refined to create a device to pull water from air?
The invention was actually created 20 years ago. Scientists combined a cluster of metal ions with a three to five other separate but functional chemical elements or molecules. The metal ions in the middle constantly steal electrons from the functional clusters bonding them together into a new star-shaped molecule. The molecule is highly reactive their shape causes any bonds between other molecules to leave holes between the molecules. Scientists named the holes pores and the entire structure became known as metal-organic framework. Since then over 20,000 types of metal-organic frameworks have been created by combining all types of metals with all types of other compounds. They are built to attract specific molecules to separate those molecules from other compounds, almost like a filter. In this case, metal-organic framework number 801 using zirconium was needed to absorb water in low humidity.
What does the device look like?
- The container is a box with a sun absorbing device on top that will allow it to heat the box while keeping the box air tight.
- The inside roof of the box requires a minimum of a kilogram of metal-organic framework crystals. Each crystal is about 5 microns in size, similar to the size of dust particles. Those crystals will be held together with a piece of thin, porous copper.
- On the bottom of the inside of the box will be a porous condenser. This condenser will lead water droplets down to a collector below it.
How does the device work?
As complicated as the parts are, the way the device operates to pull water from air is actually quite simple. It is merely a box that is opened and closed.
- At night when the air is cool, the box will be open to allow the metal-organic framework to collect water molecules from the air. Then in the morning the box will be closed.
- During the day, solar cells will absorb UV light to heat up the box.
- As the box heats up, the water collected overnight in the metal-organic framework will turn into water vapor.
- As the water becomes water vapor, it will move around inside the space in the box.
- When the water vapor comes into contact with the condenser on the bottom of the box, it cools enough to turn back into liquid form
- As each droplet forms on the condenser, it passes through it to fall into the collector at the bottom of the box.
The metal-organic framework works so well that it can collect almost 3 liters of water for each kilogram that is set up to pull water from air.
How long will it be before we see or hear about this device being used?
As we said before, the current design only uses 1 kilogram of crystallized zirconium. Just that small amount has been proven not only to pull water from air, but almost 3 liters of water from desert air! This could solve problems for Earth and Mars. If you recall the blogs “On the way to Mars don’t forget the water parts 1 and 2“, water is a major issue for the Mars missions. The only problem is that zirconium is a little expensive, but not to worry. A new kind of metal-organic framework has already been created that replaces that zirconium with aluminum! Aluminum makes the entire cost of the device much cheaper. Once all the changes have been made and proven to work just as well, then it is only a matter of time before freshwater is found easier than in a bottle or even the tap.