A New Auto-Water Collection System — Biomimetic Hydrogel
We are almost making climate change irreversible, and it has been affecting us in various aspects of our lives. As the Economist describes, “For business, water scarcity is where climate change hits home,” and I would describe “climate change as a knife, and water scarcity is the keen blade of the knife,” which hurts you the most [1].
We are in an emergency, and we need a contingent solution.
A new study was recently published on Nature, and it shows an interesting and innovative way to collect water from the air by using hydrogel with a special shape — the tree-shaped surface micro-topologies. With the remarkable design, the hydrogel was able to collect 34 L (~ 9 gallons) of water per day per square meter. It could potentially help us to access various water sources.
What is Hydrogel?
A hydrogel is made out of hydrophilic polymers that can swell in water and hold a large amount of water while at the same time maintaining the structure based on its cross-linking of individual polymer chains [2]. Hydrogels were first reported by Wichterle and Lím (1960) [3]. A hydrogel usually contains high porosity which may be up to 90%, so it will be able to contain water inside the structure.
How Does the System Work?
The researchers believe that nature has given us a perfect design, and the tree structure can be efficient to collect water. Once the tree-shaped hydrogel has been made, it will be placed into a fog (humidity ≅ 100%) environment and start collecting water in a day/night cycle.
During the night, the tree-shaped structure will be the main functional part to effectively collect water. Water droplets will likely condense onto the cones of the hydrogel tree. When the water droplet is heavy enough, then it will flow down to the surface and into the water storage.
During the daytime, on the other hand, evaporation under the sun will be more effective to remove the water from the hydrogel which contains 90% of water in the structure. This will allow us to collect water the whole day long.
While the downside is the humidity has to be close to 100% in order to start off the system, we could still potentially leverage our knowledge and play around with the system to alleviate the pressure of water scarcity. The water production capacity, according to the article, is high enough for a single family to water their yard and other simple applications. With more layers of hydrogel being installed, we will then be able to collect more water if necessary.
Conclusion
Although this article shows us the preliminary result to collect water only on a small scale, the application of hydrogel actually has the potential to be scaled up and help us solve the water scarcity problem in the near future. In addition, the whole system does not require any artificial energy input except the sun power, so it also has the potential to be utilized in various placed including urban or rural areas.
[1] For businesses, water scarcity is where climate change hits home. 2022. The Economists
[2] An Introduction to Hydrogels and Some Recent Applications. 2016
[3] Hydrophilic Gels for Biological Use. 1960. Nature
[4] All-day fresh water harvesting by microstructured hydrogel membranes. 2022. Nature
