Did you know that our atmosphere holds six times more water than all the rivers on Earth combined? It’s true! Those dew drops on grass and water droplets on a cold juice bottle are proof of this incredible natural reservoir. However, despite its abundance, 2 billion people still lack access to clean drinking water.
But there’s hope. Scientists have been working on a technique called atmospheric water harvesting (AWH) that can extract freshwater from the air. However, there have been challenges in implementing AWH on a large scale. Two key factors need to be addressed for an effective and continuous AWH system: reversible water absorption and efficient waste heat management.
Now, a team of researchers in China may have found a solution inspired by plant leaves. They have created a core-shell structural cellulose nanofiber-based aerogel called Core-Shell@CNF. This innovative material not only operates using sunlight but also produces electricity.
Producing fresh water out of thin air
The Core-Shell@CNF has a hydrophilic core that attracts water molecules and a hydrophobic shell that repels water. The core contains LiCl particles, which are excellent at absorbing water, while the shell has carbon black particles and a water-resistant PDMS coating. This design is inspired by the structure of plant leaves, which protect the interior tissue from dehydration and oxidation while allowing the transport of water molecules.
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The AWH process begins at night when the aerogel absorbs water. As air with water vapor passes through the material, the LiCl particles inside absorb the water molecules. The hydrated salts turn into a liquid film and then a salty solution, while the hydrophobic shell prevents water from leaking outside. This combination allows the Core-Shell@CNF to continuously gather water.
During the day, the carbon black particles absorb sunlight and heat up, increasing the temperature inside the aerogel. This causes the salty solution to release water vapor, re-forming the original salt. The aerogel’s porous structure aids in transferring heat and water molecules, making the desorption process effective.
The researchers conducted multiple absorption-desorption cycles to test the limits of their AWH material and improve its efficiency. They made several design improvements, resulting in a final aerogel structure with fewer pores and thicker external walls. These changes enhanced the material’s hydrophobicity and mechanical strength.
In outdoor tests, each kilogram of the aerogel collected a bit under a gram of freshwater in 24 hours. While the researchers aim to further increase efficiency, the collected water already met the drinking water requirements of the World Health Organization and the US Environmental Protection Agency.
A recent breakthrough in material science has yielded a sun-powered material capable of generating clean water and electricity simultaneously. Developed by researchers from the University of Central Florida in collaboration with the U.S. Air Force, the innovative material is made from polyurethane nanoparticles and exhibits remarkable properties.
The sun-powered material is capable of trapping and storing solar energy, which is then transposed into useful forms of energy. This process happens through a number of steps in which solar radiation is first absorbed by the nanoparticles and then converted to heat. This heat is then used to power a water splitting process, which produces clean water, oxygen, and hydrogen. The hydrogen can then be converted to electricity via fuel cells.
This remarkable material has the potential to be used in a number of applications from powering remote areas to powering devices. Not only can the material produce clean water and electricity, but it can also be used to power sensors, water pumps, and other such technologies that are often needed in remote or hard-to-reach areas.
In addition to its use in powering devices, the material could also be used to provide clean water to areas in need. The material can absorb sunlight and then convert it into clean water, avoiding traditional methods of water purification which can be cost-prohibitive.
Overall, this innovative sun-powered material has the potential to revolutionize the way we power our devices and produce clean water in remote or hard-to-reach areas. The joint effort between the University of Central Florida and the U.S. Air Force is a promising step in developing this technology.
