Aerogel: as long you have air, you’ve got a water!
When you are planning a long cruise, among the worries about the technical condition of the yacht, one literally vital question often remains not solved. It’s about how to get fresh water in case the reserves are depleted and the land is not yet visible on the horizon. It turned out that a way was found to extract drinking water directly from the surrounding air!
Drinking water is a valuable resource. Finding or obtaining water can be very difficult, especially in remote corners of the world. And when you spend a lot of time hiking or traveling far from civilization, the only option is to stock up on bottled mineral water. But plastic bottles take up a lot of space, and the environmental issue is embarrassing.
So, if you have a long trip away from the coast or supermarkets, how to replenish your supplies of clean water? In theory, water is easy to obtain: you have to combine two hydrogen atoms and one oxygen atom. But it is not enough just to mix hydrogen with oxygen. You also need energy, because the chemical reaction of hydrogen with oxygen can end in a big explosion! And if there is no easy way to get water from atoms, where do you get it from? Recently, more and more often you can hear about experiments, successful and not so, to extract water from various sources, including air.
Scientists in Singapore (NUS) have created an easy-to-make sponge-like material that pulls water molecules out of the air and then condenses them into a liquid. The whole process does not require connecting external power supplies. No electricity or heating needed! Water is extracted by aerogel, or rather, its exceptional properties.
For the first time, such a concept as aerogel was talked about back in 1931, when it became the subject of a dispute between two American scientists. It was then that Stephen Kistler and Charles Hude decided to find out what would happen if the liquid was removed from the gel they studied, whether it would then retain a solid molecular structure. Aerogel is a combination of liquid and solid particles, a jelly-like material that is formed by a kind of skeleton – a three-dimensional structure. Small miniature pores of the material give the gel rigidity. Aerogels are so transparent that they are almost impossible to see against a light background.
In addition, it is the lightest material containing 99.8% air. In sunlight, this smart system is able to increase the absorption of air, almost 100% water from it. In laboratory tests, the aerogel condensed water without interruption for several months. The brighter the sun shines, the more water the aerogel will pick up from the air. Although less productive, the process of obtaining water continues in cloudy weather. And all this can be done autonomously, with minimal energy consumption. To get up to 17 liters of drinking water per day, it is enough to stock up on one kilogram of new aerogel.
Although there are many available sources, aerogels are mostly made from silicon dioxide. For this, the gel is brought to a phase in which the boundary between the liquid and gaseous state of the substance disappears in the material. Carbon dioxide goes to its supercritical point. This process is performed several times to ensure that all liquid is removed from the gel.
So far, the only drawback of the aerogel has been found: it is incredibly light, so a kilogram of substance takes up very large volumes of space. But in any case, the new invention can be applied where the issue of storing and obtaining fresh water is especially acute. And what’s important: the researchers tested the water and found that it meets the standards of the World Health Organization.
Those considering crossing the ocean or traveling on a yacht to hard-to-reach places should make sure they have an adequate supply of water, even if the crossing takes a long time. Of course, filling stations, filtration, purification, hydraulic installations, drainage systems – there are many ways that can be used to solve the issue of drinking water. But now you can safely add a new aerogel to them.
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