https://nazology.net/archives/155759
For most of us, we take it for granted that if we turn on the tap, water will flow out of the tap.
In fact, about two-thirds of the world's population suffers from water shortages, and it is estimated that "about 40% of the world's annual water demand will not be met by 2030.
Even in Japan, where water systems are well equipped, water will continue to be inadequately available in disaster-stricken areas.
To address these challenges, Shan-Yu Lee and his research team at the Massachusetts Institute of Technology (MIT) in the United States have developed a new system to collect water from the atmosphere.
The system is thought to be able to produce two to five times more potable water than conventional systems and will work in extremely arid regions such as deserts.
Details of the research were published in the scientific journal ACS Energy Letters on June 26, 2024.
Small, adsorbent 'fins' collect humidity rather than swim through water
https://www.eurekalert.org/news-releases/1048856?
Harvesting Drinking Water From Air With Innovative Absorbent Fins
https://scitechdaily.com/harvesting-drinking-water-from-air-with-innovative-absorbent-fins/
Design of a Compact Multicyclic High-Performance Atmospheric Water Harvester for Arid Environments
https://doi.org/10.1021/acsenergylett.4c01061
Yasuhiro Okura
Specializes in technology-related fields. I like to understand structures such as mechanical, biological, and social structures. He is also fascinated by scientific and mysterious toys. His hobby is reading, and he is the type of person who is up in the morning after he starts reading.
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Table of Contents
How to collect water from the atmosphere to obtain drinking water
A new water generation system with a copper plate sandwiched between two copper plates! 2 to 5 times more efficient than conventional systems
How to Collect Water from the Atmosphere to Obtain Drinking Water
How to get water in the desert? / Credit:Canva
Several methods exist for obtaining drinking water in water-scarce areas.
For example, there are technologies that filter dirty muddy water to make it drinkable or convert seawater into fresh water.
However, these technologies assume that some amount of water, whether dirty or containing salt, is present in the area.
So how can drinking water be obtained in areas such as deserts, where it is extremely dry and not even puddles exist?
As one way to do so, scientists have long focused on "systems that collect water from the air.
This system uses an "adsorbent" to absorb water from the air, which is then heated by the sun or some other heat source to extract the water.
An adsorbent captures water from the air. Image / Credit:Xiangyu Li (MIT) et al., ACS Energy Letters (2024)
Zeolites are minerals with microscopic pores.
Because water molecules and zeolite pores are close in size, zeolites have a very high adsorption capacity for water molecules and can capture water molecules from moist air.
However, to extract water from zeolite, it must be heated, and the conventional method using sunlight is not efficient.
Lee and his team wanted to use waste heat instead of sunlight.
Waste heat is a type of excess energy generated in industrial processes and power plants, and is usually wasted.
(Top) Heating using sunlight; (bottom) heating using waste heat and other resources. Many cycles of adsorption and drainage are efficient. / Credit:Xiangyu Li (MIT) et al., ACS Energy Letters (2024)
Integrating water generation systems with existing infrastructure that generates waste heat, such as factories and other buildings and transportation vehicles, could speed up the adsorption and dehydration cycles in adsorbents, as shown in the figure above.
Incidentally, the use of waste heat will also reduce the environmental impact, making the system more valuable as a "sustainable water supply system.
Several substances are used for this adsorbent, for example "zeolite" is sometimes used.
A new water generation system with a copper plate sandwiched between two copper plates! 2 to 5 times more efficient than conventional systems
The research team has designed a new system that not only utilizes waste heat, but also seeks further efficiency.
Their new system uses copper-based adsorption fins.
New water collection system. Copper plates are sandwiched between the fins / Credit:Xiangyu Li (MIT) et al, ACS Energy Letters (2024)
The surfaces of the fins are coated with zeolite as an adsorbent, as before.
Then, by arranging multiple thin fins with a small space between them, the surface that moist air comes in contact with is widened, enabling water to be efficiently adsorbed.
In addition, a copper plate is sandwiched inside the fins.
The fins are heated using waste heat, and copper plates have advantages in terms of high thermal conductivity and corrosion resistance.
And in a proof-of-concept experiment conducted by the research team, a device with 10 fins spaced approximately 2 mm apart was used.
The new system produces drinking water from air. Two to five times more efficient than conventional systems / Credit:Xiangyu Li (MIT)_Small, adsorbent 'fins' collect humidity rather than swim through water (2024 (EurekAlert)
In this device, the fins were saturated with moisture within an hour and the water could be released by heating.
By repeating 24 collection and release cycles, we found that 1.3 liters of potable water per liter of adsorbent could be produced per day in an environment with 30% humidity.
This is two to five times more efficient than conventional systems.
Furthermore, because it uses waste heat, it is also very energy efficient.
If this new system develops, it will be able to supply drinking water in areas where water shortages are severe.
In particular, it may play an active role in arid regions such as deserts, and great expectations are being pinned on it.
Translated with DeepL.com (free version)
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