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Madrid, November 27 (EUROPA PRESS) .- It has been shown that an economical hydrogel material was able to effectively capture the water from the air even under conditions low humidity, then release it at the request of the user.
A new study from KAUST (University of Science and Technology King Abdullah) suggests that a simple device capable of capturing its own weight in the ambient air and then releasing this water Sun-heated can be a new source of safe water. drink in remote and arid regions.
On a global scale, the Earth 's air contains nearly 13 billion tons of water, a vast, renewable reservoir of clean water. The testing of many materials and devices developed to take advantage of this water source has proven to be too inefficient, expensive or complex for practical use. A prototype device developed by Peng Wang of the Centry water desalination and reuse team could finally solve this problem.
At the heart of the device is a cheap, stable and non-toxic chloride, calcium chloride. Renyuan Li, a student of Wang's team, explains Renyuan Li, a student of Wang's team. This deliquescent salt has such an affinity for water that it absorbs such a large amount of ambient air vapor that a puddle of liquid is formed. "Deliquescent salt can dissolve by absorbing moisture from the surface, air," he says.
Calcium chloride has great potential for water recovery, but the fact that it is converted from a solid liquid into a salty liquid after absorbing water constitutes a major obstacle to its use as a water catchment device, says Li.
"Systems using liquid sorbents are very complicated," he says. To solve this problem, the researchers incorporated the salt into a polymer called hydrogel, which can hold a large volume of water while remaining solid. They also added a small amount of carbon nanotubes, 0.42% by weight, to ensure release of the captured water vapor. Carbon nanotubes very effectively absorb sunlight and convert captured energy into heat.
The team has incorporated 35 grams of this material into a single prototype. Remained outside during the night, he captured 37 grams of water in one night when the relative humidity was about 60%. The next day, after 2.5 hours of natural irradiation in the sun, most of the absorbed water was released and collected inside the device.
"The most remarkable aspects of the hydrogel are its high performance and low cost," says Li. If the prototype was extended to produce 3 liters of water a day, the minimum water required for an adult, the cost of absorbent hydrogel material would cost only half a dollar a day.
The next step will be to refine the absorbent hydrogel so that it releases the water collected continuously rather than in batches, Wang explains.
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