A team of researchers has developed a porous aerogel material with the ability to convert seawater into potable water using only sunlight. The aerogel design has a sponge-like structure, fabricated from carbon nanotubes and cellulose nanofibers using 3D printing, offering an efficient solution for desalination without energy consumption.
Aerogel material and its solar evaporation technology
The aerogel printed in successive layers on a frozen surface has uniform vertical microchannels of about 20 micrometers. This structure allows high efficiency in water conduction and steam generation by solar energy.
During the outdoor tests, the material was placed in a beaker of salt water covered with a transparent plastic dome. Solar radiation heated the top of the aerogel, evaporating the water and leaving the salt behind. This vapor condensed in the dome and dripped into a collecting vessel, producing potable water.
Moreover, one of the advantages of the system is the evaporation efficiency, which manages to remain constant in pieces of multiple dimensions. Each of the tests with blocks from 1 to 8 centimeters showed a stable conversion rate. This property overcomes limitations common in previous aerogel-based desalinationaerogel-based desalination technologies, which lost performance in large formats.
This system was able to produce approximately three tablespoons of clean water after six hours of exposure to the sun. Although the volume is modest, the research marks an important advance towards passive seawater treatment systems. The simplicity of the design and the absence of electrical components components make it feasible for implementation in remote or water-scarce regions.
The study was supported by entities in Hong Kong and mainland China, including the National Natural Science Foundation and the Hong Kong Polytechnic University. The researchers are working on scaling up the prototype to produce larger volumes while maintaining its low energy impact and high evaporation efficiency.
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Source: EurekAlert
Photo: Adapted from ACS Energy Letters 2025, DOI: 10.1021/acsenergylett.5c01233
