drinking water This new material pulls clean drinking water straight out of the air

[Reefa]

This could solve a lot of problems.

 

One of the ways of sourcing drinking water in areas afflicted by drought is by harvesting it from the air, and now a new material developed by scientists in the US could make this tricky feat easier than ever.

 

Researchers at Harvard University have taken inspiration from a variety of water-collecting traits in different natural species to develop what could be an unrivalled composite system for harvesting and transporting atmospheric H20.

 

"Everybody is excited about bio-inspired materials research," said chemical biologist Joanna Aizenberg from Harvard's Wyss Institute for Biologically Inspired Engineering. "However, so far, we tend to mimic one inspirational natural system at a time."

 

Instead, the team's system combines elements from three distinct plant and animal species to create a material that they claim outperforms other synthetic surfaces designed to trap condensation.

 

According to the researchers, the major challenges in harvesting water from the air lie in controlling the size, speed, and direction of water droplets as they form and flow on a surface. At the core of their solution to this problem, the researchers copy the external bumps of Namib desert beetles, which help the insect to collect water droplets on its shell.

 

 

Scientists already knew that the bumps' hydrophilic (water-attracting) tops and hydrophobic (water-repelling) surroundings helped them collect water, but Aizenberg's team realised that the convex shape of the protrusions themselves might also be able to harvest water too.

 

Using modelling, the team found that this natural water-trapping mechanism could be enhanced by mimicking the geometry and slopes of cactus spines, which help drive collected droplets down the slopes.

 

By combining this further with a nano-coating designed to emulate the slippery surfaces of pitcher plants, the material facilitates greater droplet formation as the water beads downwards.

 

"We experimentally found that the geometry of bumps alone could facilitate condensation," said one of the researchers, Kyoo-Chul Park. "By optimising that bump shape through detailed theoretical modelling and combining it with the asymmetry of cactus spines and the nearly friction-free coatings of pitcher plants, we were able to design a material that can collect and transport a greater volume of water in a short time compared to other surfaces."

 

The tandem effect of the system – together with a technology developed by the researchers called Slippery Liquid-Infused Porous Surfaces – helps the material collect water in ways that could otherwise prove impossible.

 

"Bumps that are rationally designed to integrate these mechanisms are able to grow and transport large droplets even against gravity and overcome the effect of an unfavourable temperature gradient," the authors write in their paper, published in Nature.

 

Not only could this technique help to harvest water from the air in areas affected by water shortages, but it could also be of use to enhance condensation in industrial machinery.

 

"Thermal power plants, for example, rely on condensers to quickly convert steam to liquid water," said one of the team, Philseok Kim. "This design could help speed up that process and even allow for operation at a higher temperature, significantly improving the overall energy efficiency."

 

With about 1.2 billion people around the world living with water scarcity and two-thirds of the global population experiencing water shortages on a monthly basis, the potential of technology like this could make a huge difference to so many lives.

http://www.sciencealert.com/this-new-material-pulls-clean-drinking-water-straight-out-of-the-air

[luisam]

Interesting information, though it nowhere comments the expected productoion rate of this device. By the way you can read in reference about a similar technology developed in Australia. This self-filling water bottle harvests clean drinking water from the air at a rate of 0.5 litres per hour. - might be about 12 litres per day. You won't fill you jakuzzi but it's quite enough for daily basic individual requierments.

 

An Austrian start-up has revealed plans to start selling a self-filling water bottle that extracts humidity from the air and condenses it into drinkable water at a rate of up to 0.5 litres per hour - provided it’s a really humid day.

Developed by the team at Fontus, the solar-powered device uses hydrophobic surfaces to repel and funnel the drops of condensation in the bottle, which means so as long as the air around you isn’t too polluted, you'll have access have a constant supply of clean drinking water.

 

"This is simply condensation of the humidity that is contained in the air," Fontus founder Retezár Kristof told Denise Chow at Live Science. "You always have a certain percentage of humidity in the air, it doesn't matter where you are - even in the desert. That means you would always potentially be able to extract that humidity from the air."

The water bottle - which is currently getting the crowdfunding treatment to facilitate mass-production - is being marketed as an aid for long-distance cyclists who don’t have time to stop off and top-up. When it goes on sale, it’ll come with a bike-attachment, as seen in the video below.

That’s the first-world application of the technology, but the benefits are obvious for the 1.2 billion people in the world who are living in areas where clean water is scarce.

"The idea was to solve a global problem: water issues in areas of the world where there is very little groundwater but very high humidity," Retezár said. "My intent was to invent a machine or device that would be able to filter the humidity in the air and turn it into drinkable water."

The device is made up of a solar panel, a condensing chamber lined with hydrophobic surfaces, and a very basic filter to keep dust, dirt, and bugs out of the mix. It works by taking in warm, humid air, which is condensed down into water droplets that are funnelled into the water bottle below because the hydrophobic surfaces prevent them from sticking. 

"Because they're hydrophobic, they immediately repel the condensed water that they created, so you get a drop flow [into the bottle]," Retezár told Live Science. "Basically, you're taking air in a vapour state and converting it into a liquid state."

When it hits the market, the bottle will come in two models - the 'Airo', and the 'Ryde', which is being made specifically for cyclists. Retezár and his team say if you've got with temperatures 30 to 40 degrees Celsius (86 degrees to 104 degrees Fahrenheit) and 80 to 90 percent humidity, you can hit that impressive 0.5 litres per hour fill-rate.

The developers have also mentioned the possibility of adding a carbon filter to the mix, which could be used to filter out clean water from more polluted areas.

Now, all of this does sound pretty awesome, but of course it does - Fontus wants to sell a lot of these things. While the principle of the thing sounds like it would work as advertised, until we see tests from independent parties, we have to remain skeptical. 

According to Eric Mack at Gizmag, the company says it plans to release third-party white paper data at some point, which will include "reference temperature, humidity settings, duration, and resultant volume of water created", and separate 'validation tests' are going to be funded by some of those crowdfunding dollars.

 

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